source: git/kernel/gfan.cc @ e2e3ad

/*
Compute the Groebner fan of an ideal
$Author: monerjan $
$Date: 2009/11/03 06:57:32 $
$Header: /usr/local/Singular/cvsroot/kernel/gfan.cc,v 1.103 2009/11/03 06:57:32 monerjan Exp $
$Id$
*/

#include "mod2.h"

#ifdef HAVE_GFAN

#include "kstd1.h"
#include "kutil.h"
#include "intvec.h"
#include "polys.h"
#include "ideals.h"
#include "kmatrix.h"
#include "fast_maps.h"  //Mapping of ideals
#include "maps.h"
#include "ring.h"
#include "structs.h"
#include "../Singular/lists.h"
#include "prCopy.h"
#include <iostream>
#include <bitset>
#include <fstream>      //read-write cones to files
#include <gmp.h>
#include <string>
#include <sstream>
#include <time.h>

//#include <gmpxx.h>

/*DO NOT REMOVE THIS*/
#ifndef GMPRATIONAL
#define GMPRATIONAL
#endif

//Hacks for different working places
#define p800

#ifdef UNI
#include "/users/urmel/alggeom/monerjan/cddlib/include/setoper.h" //Support for cddlib. Dirty hack
#include "/users/urmel/alggeom/monerjan/cddlib/include/cdd.h"
#endif

#ifdef HOME
#include "/home/momo/studium/diplomarbeit/cddlib/include/setoper.h"
#include "/home/momo/studium/diplomarbeit/cddlib/include/cdd.h"
#endif

#ifdef ITWM
#include "/u/slg/monerjan/cddlib/include/setoper.h"
#include "/u/slg/monerjan/cddlib/include/cdd.h"
#include "/u/slg/monerjan/cddlib/include/cddmp.h"
#endif

#ifdef p800
#include "../../cddlib/include/setoper.h"
#include "../../cddlib/include/cdd.h"
#include "../../cddlib/include/cddmp.h"
#endif

#ifndef gfan_DEBUG
//#define gfan_DEBUG
#ifndef gfan_DEBUGLEVEL
#define gfan_DEBUGLEVEL 1
#endif
#endif

#include <gfan.h>
using namespace std;

/**
*\brief Class facet
*       Implements the facet structure as a linked list
*
*/
                
/** \brief The default constructor for facets
*/
facet::facet()                  
{
        // Pointer to next facet.  */
        /* Defaults to NULL. This way there is no need to check explicitly */
        this->fNormal=NULL;
        this->interiorPoint=NULL;               
        this->UCN=0;
        this->codim2Ptr=NULL;
        this->codim=1;          //default for (codim-1)-facets
        this->numCodim2Facets=0;
        this->flipGB=NULL;
        this->isIncoming=FALSE;
        this->next=NULL;
        this->prev=NULL;                
        this->flipRing=NULL;    //the ring on the other side
        this->isFlippable=FALSE;
}
                
/** \brief Constructor for facets of codim >= 2
* Note that as of now the code of the constructors is only for facets and codim2-faces. One
* could easily change that by renaming numCodim2Facets to numCodimNminusOneFacets or similar
*/
facet::facet(int const &n)
{
        this->fNormal=NULL;
        this->interiorPoint=NULL;                       
        this->UCN=0;
        this->codim2Ptr=NULL;
        if(n>1)
        {
                this->codim=n;
        }//NOTE Handle exception here!                  
        this->numCodim2Facets=0;
        this->flipGB=NULL;
        this->isIncoming=FALSE;
        this->next=NULL;
        this->prev=NULL;
        this->flipRing=NULL;
        this->isFlippable=FALSE;
}
                
/** \brief The copy constructor
*/
facet::facet(const facet& f)
{
}
                
/** The default destructor */
facet::~facet()
{
        delete this->fNormal;
        delete this->interiorPoint;
        /* Cleanup the codim2-structure */
        if(this->codim==2)
        {
                facet *codim2Ptr;
                codim2Ptr = this->codim2Ptr;
                while(codim2Ptr!=NULL)
                {
                        delete codim2Ptr->fNormal;
                        codim2Ptr = codim2Ptr->next;
                }
        }
        delete this->codim2Ptr;
        idDelete((ideal *)&this->flipGB);
        rDelete(this->flipRing);
        this->flipRing=NULL;
        //this=NULL;
}
                
                
/** \brief Comparison of facets*/
bool facet::areEqual(facet &f, facet &g)
{
        bool res = TRUE;
        intvec *fNormal = new intvec(pVariables);
        intvec *gNormal = new intvec(pVariables);
        fNormal = f.getFacetNormal();
        gNormal = g.getFacetNormal();
        if((fNormal == gNormal))//||(gcone::isParallel(fNormal,gNormal)))
        {
                if(f.numCodim2Facets==g.numCodim2Facets)
                {
                        facet *f2Act;
                        facet *g2Act;
                        f2Act = f.codim2Ptr;
                        g2Act = g.codim2Ptr;
                        intvec *f2N = new intvec(pVariables);
                        intvec *g2N = new intvec(pVariables);
                        while(f2Act->next!=NULL && g2Act->next!=NULL)
                        {
                                for(int ii=0;ii<f2N->length();ii++)
                                {
                                        if(f2Act->getFacetNormal() != g2Act->getFacetNormal())
                                        {
                                                res=FALSE;                                                              
                                        }
                                        if (res==FALSE)
                                                break;
                                }
                                if(res==FALSE)
                                        break;
                                
                                f2Act = f2Act->next;
                                g2Act = g2Act->next;
                        }//while
                }//if           
        }//if
        else
        {
                res = FALSE;
        }
        return res;
}
                
/** Stores the facet normal \param intvec*/
void facet::setFacetNormal(intvec *iv)
{
        this->fNormal = ivCopy(iv);                     
}
                
/** Hopefully returns the facet normal */
intvec *facet::getFacetNormal()
{                               
        return ivCopy(this->fNormal);
}
                
/** Method to print the facet normal*/
void facet::printNormal()
{
        fNormal->show();
}
                
/** Store the flipped GB*/
void facet::setFlipGB(ideal I)
{
        this->flipGB=idCopy(I);
}
                
/** Return the flipped GB*/
ideal facet::getFlipGB()
{
        return this->flipGB;
}
                
/** Print the flipped GB*/
void facet::printFlipGB()
{
#ifndef NDEBUG
        idShow(this->flipGB);
#endif
}
                
/** Set the UCN */
void facet::setUCN(int n)
{
        this->UCN=n;
}
                
/** \brief Get the UCN 
* Returns the UCN iff this != NULL, else -1
*/
int facet::getUCN()
{
        if(this!=NULL && ( this!=(facet *)0xfbfbfbfb || this!=(facet *)0xfbfbfbfbfbfbfbfb) )
//      if(this!=NULL && ( this->fNormal!=(intvec *)0xfbfbfbfb || this->fNormal!=(intvec *)0xfbfbfbfbfbfbfbfb) )
                return this->UCN;
        else
                return -1;
}
                
/** Store an interior point of the facet */
void facet::setInteriorPoint(intvec *iv)
{
        this->interiorPoint = ivCopy(iv);
}
                
intvec *facet::getInteriorPoint()
{
        return this->interiorPoint;
}       
                
/** \brief Debugging function
* prints the facet normal an all (codim-2)-facets that belong to it
*/
void facet::fDebugPrint()
{                       
        facet *codim2Act;                       
        codim2Act = this->codim2Ptr;
        intvec *fNormal;
        fNormal = this->getFacetNormal();
        intvec *f2Normal;
        cout << "=======================" << endl;
        cout << "Facet normal = (";
        fNormal->show(1,1);
        cout << ")"<<endl;      
        cout << "-----------------------" << endl;
        cout << "Codim2 facets:" << endl;
        while(codim2Act!=NULL)
        {
                f2Normal = codim2Act->getFacetNormal();
                cout << "(";
                f2Normal->show(1,0);
                cout << ")" << endl;
                codim2Act = codim2Act->next;
        }
        cout << "=======================" << endl;
}               
                
//friend class gcone;   //Bad style


/**
*\brief Implements the cone structure
*
* A cone is represented by a linked list of facet normals
* @see facet
*/


/** \brief Default constructor. 
 *
 * Initialises this->next=NULL and this->facetPtr=NULL
 */
gcone::gcone()
{
        this->next=NULL;
        this->prev=NULL;
        this->facetPtr=NULL;    //maybe this->facetPtr = new facet();                   
        this->baseRing=currRing;
        this->counter++;
        this->UCN=this->counter;                        
        this->numFacets=0;
        this->ivIntPt=NULL;
}
                
/** \brief Constructor with ring and ideal
 *
 * This constructor takes the root ring and the root ideal as parameters and stores 
 * them in the private members gcone::rootRing and gcone::inputIdeal
 * This constructor is only called once in the computation of the Gröbner fan,
 * namely for the very first cone. Therefore pred is set to 1.
 * Might set it to this->UCN though...
 * Since knowledge of the root ring is only needed when using reverse search,
 * this constructor is not needed when using the "second" method
*/
gcone::gcone(ring r, ideal I)
{
        this->next=NULL;
        this->prev=NULL;
        this->facetPtr=NULL;                    
//      this->rootRing=r;
        this->inputIdeal=I;
        this->baseRing=currRing;
        this->counter++;
        this->UCN=this->counter;
        this->pred=1;
        this->numFacets=0;
        this->ivIntPt=NULL;
}
                
/** \brief Copy constructor 
 *
 * Copies a cone, sets this->gcBasis to the flipped GB
 * Call this only after a successful call to gcone::flip which sets facet::flipGB
*/              
gcone::gcone(const gcone& gc, const facet &f)
{
        this->next=NULL;
//      this->prev=(gcone *)&gc; //comment in to get a tree
        this->prev=NULL;
        this->numVars=gc.numVars;                                               
        this->counter++;
        this->UCN=this->counter;
        this->pred=gc.UCN;                      
        this->facetPtr=NULL;
        this->gcBasis=idCopy(f.flipGB);
        this->inputIdeal=idCopy(this->gcBasis);
        this->baseRing=rCopy(f.flipRing);
        this->numFacets=0;
        this->ivIntPt=NULL;
//      this->rootRing=NULL;
        //rComplete(this->baseRing);
        //rChangeCurrRing(this->baseRing);
}
                
/** \brief Default destructor 
*/
gcone::~gcone()
{
        if(this->gcBasis!=NULL)
                idDelete((ideal *)&this->gcBasis);
        if(this->inputIdeal!=NULL)
                idDelete((ideal *)&this->inputIdeal);
//      if (this->rootRing!=NULL && this->rootRing!=(ip_sring *)0xfefefefefefefefe)
//              rDelete(this->rootRing);
        //rDelete(this->baseRing);
        facet *fAct;
        facet *fDel;
        /*Delete the facet structure*/
        fAct=this->facetPtr;
        fDel=fAct;
        while(fAct!=NULL)
        {
                fDel=fAct;
                fAct=fAct->next;
                delete fDel;
        }
        //dd_FreeMatrix(this->ddFacets);
}                       
        
int gcone::getCounter()
{
        return this->counter;
}
        
/** \brief Set the interior point of a cone */
void gcone::setIntPoint(intvec *iv)
{
        this->ivIntPt=ivCopy(iv);
}
                
/** \brief Return the interior point */
intvec *gcone::getIntPoint()
{
        return this->ivIntPt;
}
                
/** \brief Print the interior point */
void gcone::showIntPoint()
{
        ivIntPt->show();
}
                
/** \brief Print facets
 * This is mainly for debugging purposes. Usually called from within gdb
 */
void gcone::showFacets(short codim)
{
        facet *f;
        switch(codim)
        {
                case 1:
                        f = this->facetPtr;
                        break;
                case 2:
                        f = this->facetPtr->codim2Ptr;
                        break;
        }                       
                        
        intvec *iv;                     
        while(f!=NULL)
        {
                iv = f->getFacetNormal();
                cout << "(";
                iv->show(1,0);                          
                if(f->isFlippable==FALSE)
                        cout << ")* ";
                else
                        cout << ") ";
                f=f->next;
        }
        cout << endl;
}
                
/** For debugging purposes only */
void gcone::showSLA(facet &f)
{
        facet *fAct;
        fAct = &f;
        facet *codim2Act;
        codim2Act = fAct->codim2Ptr;
        intvec *fNormal;
        intvec *f2Normal;
        cout << endl;
        while(fAct!=NULL)
        {
                fNormal=fAct->getFacetNormal();
                cout << "(";
                fNormal->show(1,0);
                if(fAct->isFlippable==TRUE)
                        cout << ") ";
                else
                        cout << ")* ";
                codim2Act = fAct->codim2Ptr;
                cout << " Codim2: ";
                while(codim2Act!=NULL)
                {
                        f2Normal = codim2Act->getFacetNormal();
                        cout << "(";
                        f2Normal->show(1,0);
                        cout << ") ";
                        codim2Act = codim2Act->next;
                }
                cout << "UCN = " << fAct->getUCN() << endl;                             
                fAct = fAct->next;
        }
}
                
void gcone::idDebugPrint(ideal const &I)
{
        int numElts=IDELEMS(I);
        cout << "Ideal with " << numElts << " generators" << endl;
        cout << "Leading terms: ";
        for (int ii=0;ii<numElts;ii++)
        {
                pWrite0(pHead(I->m[ii]));
                cout << ",";
        }
        cout << endl;
}

void gcone::invPrint(ideal const &I)
{
//      int numElts=IDELEMS(I);
//      cout << "inv = ";
//      for(int ii=0;ii<numElts;ii++);
//      {
//              pWrite0(pHead(I->m[ii]));
//              cout << ",";
//      }
//      cout << endl;
}

bool gcone::isMonomial(ideal const &I)
{
        bool res = TRUE;
        for(int ii=0;ii<IDELEMS(I);ii++)
        {
                if(pLength((poly)I->m[ii])>1)
                {
                        res = FALSE;
                        break;
                }                                                
        }
        return res;
}
                
/** \brief Set gcone::numFacets */
void gcone::setNumFacets()
{
}
                
/** \brief Get gcone::numFacets */
int gcone::getNumFacets()
{
        return this->numFacets;
}
                
int gcone::getUCN()
{
        if( this!=NULL && ( this!=(gcone * const)0xfbfbfbfbfbfbfbfb && this!=(gcone * const)0xfbfbfbfb ) )
                return this->UCN;
        else
                return -1;
}

int gcone::getPredUCN()
{
        return this->pred;
}

/** \brief Compute the normals of the cone
 *
 * This method computes a representation of the cone in terms of facet normals. It takes an ideal
 * as its input. Redundancies are automatically removed using cddlib's dd_MatrixCanonicalize.
 * Other methods for redundancy checkings might be implemented later. See Anders' diss p.44.
 * Note that in order to use cddlib a 0-th column has to be added to the matrix since cddlib expects 
 * each row to represent an inequality of type const+x1+...+xn <= 0. While computing the normals we come across
 * the set \f$ \partial\mathcal{G} \f$ which we might store for later use. C.f p71 of journal
 * As a result of this procedure the pointer facetPtr points to the first facet of the cone.
 *
 * Optionally, if the parameter bool compIntPoint is set to TRUE the method will also compute
 * an interior point of the cone.
                 */
void gcone::getConeNormals(ideal const &I, bool compIntPoint)
{
        poly aktpoly;
        int rows;                       // will contain the dimensions of the ineq matrix - deprecated by
        dd_rowrange ddrows;
        dd_colrange ddcols;
        dd_rowset ddredrows;            // # of redundant rows in ddineq
        dd_rowset ddlinset;             // the opposite
        dd_rowindex ddnewpos;             // all to make dd_Canonicalize happy
        dd_NumberType ddnumb=dd_Integer; //Number type
        dd_ErrorType dderr=dd_NoError;          
        //Compute the # inequalities i.e. rows of the matrix
        rows=0; //Initialization
        for (int ii=0;ii<IDELEMS(I);ii++)
        {
                aktpoly=(poly)I->m[ii];
                rows=rows+pLength(aktpoly)-1;
        }

        dd_rowrange aktmatrixrow=0;     // needed to store the diffs of the expvects in the rows of ddineq
        dd_set_global_constants();
        ddrows=rows;
        ddcols=this->numVars;
        dd_MatrixPtr ddineq;            //Matrix to store the inequalities                      
        ddineq=dd_CreateMatrix(ddrows,ddcols+1); //The first col has to be 0 since cddlib checks for additive consts there
                
        // We loop through each g\in GB and compute the resulting inequalities
        for (int i=0; i<IDELEMS(I); i++)
        {
                aktpoly=(poly)I->m[i];          //get aktpoly as i-th component of I
                //simpler version of storing expvect diffs
                int *leadexpv=(int*)omAlloc(((this->numVars)+1)*sizeof(int));
                int *tailexpv=(int*)omAlloc(((this->numVars)+1)*sizeof(int));
                pGetExpV(aktpoly,leadexpv);
                while(pNext(aktpoly)!=NULL)
                {
                        aktpoly=pNext(aktpoly);
                        pGetExpV(aktpoly,tailexpv);
                        for(int kk=1;kk<=this->numVars;kk++)
                        {
                                dd_set_si(ddineq->matrix[(dd_rowrange)aktmatrixrow][kk],leadexpv[kk]-tailexpv[kk]);
                        }
                        aktmatrixrow += 1;
                }
                omFree(tailexpv);
                omFree(leadexpv);       
        } //for
#if true
        /*Let's make the preprocessing here. This could already be done in the above for-loop,
        * but for a start it is more convenient here.
        * We check the necessary condition of FJT p.18
        * Quote: [...] every non-zero spoly should have at least one of its terms in inv(G)
        */
        ideal initialForm=idInit(IDELEMS(I),1);
        intvec *gamma=new intvec(this->numVars);
        int falseGammaCounter=0;
        int *redRowsArray=NULL;
        int num_alloc=0;
        int num_elts=0; 
        for(int ii=0;ii<ddineq->rowsize;ii++)
        {
                //read row ii into gamma
                double tmp;     
                for(int jj=1;jj<=this->numVars;jj++)
                {
                        tmp=mpq_get_d(ddineq->matrix[ii][jj]);
                        (*gamma)[jj-1]=(int)tmp;
                }
                computeInv((ideal&)I,initialForm,*gamma);
                //Create leading ideal
                ideal L=idInit(IDELEMS(initialForm),1);
                for(int jj=0;jj<IDELEMS(initialForm);jj++)
                {
                        L->m[jj]=pCopy(pHead(initialForm->m[jj]));
                }               
                
                LObject *P = new sLObject();
                memset(P,0,sizeof(LObject));

                for(int jj=0;jj<=IDELEMS(initialForm)-2;jj++)
                {
                        bool isMaybeFacet=FALSE;
                        P->p1=initialForm->m[jj];       //build spolys of initialForm in_v

                        for(int kk=jj+1;kk<=IDELEMS(initialForm)-1;kk++)
                        {
                                P->p2=initialForm->m[kk];
                                ksCreateSpoly(P);                                                       
                                if(P->p!=NULL)  //spoly non zero=?
                                {       
                                        poly p=pInit();                 
                                        poly q=pInit();
                                        p=pCopy(P->p);
                                        q=pHead(p);     //Monomial q
                                        isMaybeFacet=FALSE;
                                        while(p!=NULL)
                                        {
                                                q=pHead(p);                                             
//                                              unsigned long sevSpoly=pGetShortExpVector(q);
//                                              unsigned long not_sevL;                                         
                                                for(int ll=0;ll<IDELEMS(L);ll++)
                                                {
//                                                      not_sevL=~pGetShortExpVector(L->m[ll]);//                                       
                                                        //if(!(sevSpoly & not_sevL) && pLmDivisibleBy(L->m[ll],q) )//i.e. spoly is in L 
                                                        if(pLmEqual(L->m[ll],q) || pDivisibleBy(L->m[ll],q))
                                                        {                                                       
                                                                isMaybeFacet=TRUE;
                                                                break;//for
                                                        }
                                                }
                                                if(isMaybeFacet==TRUE)
                                                {                                                       
                                                        break;//while(p!=NULL)
                                                }
                                                p=pNext(p);                                             
                                        }//while
                                        if(isMaybeFacet==FALSE)
                                        {
                                                dd_set_si(ddineq->matrix[ii][0],1);                                             
                                                if(num_alloc==0)
                                                        num_alloc += 1;
                                                else
                                                        num_alloc += 1;
                                                void *_tmp = realloc(redRowsArray,(num_alloc*sizeof(int)));
                                                if(!_tmp)
                                                        WerrorS("Woah dude! Couldn't realloc memory\n");
                                                redRowsArray = (int*)_tmp;
                                                redRowsArray[num_elts]=ii;
                                                num_elts++;
                                                //break;//for(int kk, since we have found one that is not in L  
                                                goto _start;    //mea culpa, mea culpa, mea maxima culpa
                                        }
                                }//if(P->p!=NULL)                               
                        }//for k
                }//for jj
                _start:;
                delete P;
                //idDelete(L);          
        }//for(ii<ddineq-rowsize
        
        int offset=0;//needed for correction of redRowsArray[ii]
        for( int ii=0;ii<num_elts;ii++ )
        {
                dd_MatrixRowRemove(&ddineq,redRowsArray[ii]+1-offset);//cddlib sucks at enumeration
                offset++;
        }
        free(redRowsArray);
#endif
//      cout << "Found " << falseGammaCounter << " false in " << rows << endl;
        //Maybe add another row to contain the constraints of the standard simplex?


        //Remove redundant rows here!
        //Necessary check here! C.f. FJT p18            
        dd_MatrixCanonicalize(&ddineq, &ddlinset, &ddredrows, &ddnewpos, &dderr);
        //time(&canonicalizeTac);
        //cout << "dd_MatrixCanonicalize time: " << difftime(canonicalizeTac,canonicalizeTic) << "sec" << endl;
        ddrows = ddineq->rowsize;       //Size of the matrix with redundancies removed
        ddcols = ddineq->colsize;
                        
        //ddCreateMatrix(ddrows,ddcols+1);
        ddFacets = dd_CopyMatrix(ddineq);
                        
        /*Write the normals into class facet*/
        /*The pointer *fRoot should be the return value of this function*/
        //facet *fRoot = new facet();   //instantiate new facet
        //fRoot->setUCN(this->getUCN());
        //this->facetPtr = fRoot;               //set variable facetPtr of class gcone to first facet
        facet *fAct;    //pointer to active facet
                        //fAct = fRoot;                 //Seems to do the trick. fRoot and fAct have to point to the same adress!
                        //std::cout << "fRoot = " << fRoot << ", fAct = " << fAct << endl;
        int numNonFlip=0;
        for (int kk = 0; kk<ddrows; kk++)
        {
                intvec *load = new intvec(this->numVars);       //intvec to store a single facet normal that will then be stored via setFacetNormal
                for (int jj = 1; jj <ddcols; jj++)
                {
                        double foo;
                        foo = mpq_get_d(ddineq->matrix[kk][jj]);
                        (*load)[jj-1] = (int)foo;       //store typecasted entry at pos jj-1 of load            
                }//for (int jj = 1; jj <ddcols; jj++)
                                
                /*Quick'n'dirty hack for flippability*/ 
                bool isFlip=FALSE;                                                              
                for (int jj = 0; jj<load->length(); jj++)
                {
                        intvec *ivCanonical = new intvec(load->length());
                        (*ivCanonical)[jj]=1;
//                                      cout << "dotProd=" << dotProduct(*load,*ivCanonical) << endl;
                        if (dotProduct(*load,*ivCanonical)<0)   
                                        //if (ivMult(load,ivCanonical)<0)
                        {
                                isFlip=TRUE;
                                break;  //URGHS
                        }
                        delete ivCanonical;
                }/*End of check for flippability*/
                if (isFlip==FALSE)
                {
                        this->numFacets++;
                        numNonFlip++;
                        if(this->numFacets==1)
                        {
                                facet *fRoot = new facet();
                                this->facetPtr = fRoot;
                                fAct = fRoot;
                                                
                        }
                        else
                        {
                                fAct->next = new facet();
                                fAct = fAct->next;
                        }
                        fAct->isFlippable=FALSE;
                        fAct->setFacetNormal(load);
                        fAct->setUCN(this->getUCN());
#ifdef gfan_DEBUG
                        cout << "Marking facet (";
                        load->show(1,0);
                        cout << ") as non flippable" << endl;                           
#endif
                }
                else
                {       /*Now load should be full and we can call setFacetNormal*/                                      
                        this->numFacets++;
                        if(this->numFacets==1)
                        {
                                facet *fRoot = new facet();
                                this->facetPtr = fRoot;
                                fAct = fRoot;
                        }
                        else
                        {
                                fAct->next = new facet();
                                fAct = fAct->next;
                        }
                        fAct->isFlippable=TRUE;
                        fAct->setFacetNormal(load);
                        fAct->setUCN(this->getUCN());                                   
                }//if (isFlippable==FALSE)
                delete load;                            
        }//for (int kk = 0; kk<ddrows; kk++)
                        
        //In cases like I=<x-1,y-1> there are only non-flippable facets...
        if(numNonFlip==this->numFacets)
        {                                       
                WerrorS ("Only non-flippable facets. Terminating...\n");
        }
                        
        /*
        Now we should have a linked list containing the facet normals of those facets that are
        -irredundant
        -flipable
        Adressing is done via *facetPtr
        */
                        
        if (compIntPoint==TRUE)
        {
                intvec *iv = new intvec(this->numVars);
                dd_MatrixPtr posRestr=dd_CreateMatrix(this->numVars,this->numVars+1);
                int jj=1;
                for (int ii=0;ii<=this->numVars;ii++)
                {
                        dd_set_si(posRestr->matrix[ii][jj],1);
                        jj++;                                                   
                }
                dd_MatrixAppendTo(&ddineq,posRestr);
                interiorPoint(ddineq, *iv);     //NOTE ddineq contains non-flippable facets
                this->setIntPoint(iv);  //stores the interior point in gcone::ivIntPt
                delete iv;
        }
                        
        //Compute the number of facets
        // wrong because ddineq->rowsize contains only irredundant facets. There can still be
        // non-flippable ones!
        //this->numFacets=ddineq->rowsize;
        
        //Clean up but don't delete the return value! (Whatever it will turn out to be)                 
        dd_FreeMatrix(ddineq);
        set_free(ddredrows);
        set_free(ddlinset);
        //free(ddnewpos);
        //set_free(ddlinset);
        //NOTE Commented out. Solved the bug that after facet2Matrix there were facets lost
        //THIS SUCKS
        //dd_free_global_constants();

}//method getConeNormals(ideal I)       
                
/** \brief Compute the (codim-2)-facets of a given cone
 * This method is used during noRevS
 * Additionally we check whether the codim2-facet normal is strictly positive. Otherwise
 * the facet is marked as non-flippable.
 */
void gcone::getCodim2Normals(gcone const &gc)
{
        //this->facetPtr->codim2Ptr = new facet(2);     //instantiate a (codim-2)-facet
        facet *fAct;
        fAct = this->facetPtr;          
        facet *codim2Act;
        //codim2Act = this->facetPtr->codim2Ptr;
                        
        dd_set_global_constants();
                        
        dd_MatrixPtr ddineq,P,ddakt;
        dd_rowset impl_linset, redset;
        dd_ErrorType err;
        dd_rowindex newpos;             

        //ddineq = facets2Matrix(gc);   //get a matrix representation of the cone
        ddineq = dd_CopyMatrix(gc.ddFacets);
                                
        /*Now set appropriate linearity*/
        dd_PolyhedraPtr ddpolyh;
        for (int ii=0; ii<this->numFacets; ii++)                        
        {                               
                ddakt = dd_CopyMatrix(ddineq);
                ddakt->representation=dd_Inequality;
                set_addelem(ddakt->linset,ii+1);                                
                dd_MatrixCanonicalize(&ddakt, &impl_linset, &redset, &newpos, &err);                    
                ddpolyh=dd_DDMatrix2Poly(ddakt, &err);
                P=dd_CopyGenerators(ddpolyh);                           
                /* We loop through each row of P normalize it by making all
                * entries integer ones and add the resulting vector to the
                * int matrix facet::codim2Facets */
                for (int jj=1;jj<=P->rowsize;jj++)
                {                                       
                        fAct->numCodim2Facets++;
                        if(fAct->numCodim2Facets==1)                                    
                        {                                               
                                fAct->codim2Ptr = new facet(2);                                         
                                codim2Act = fAct->codim2Ptr;
                        }
                        else
                        {
                                codim2Act->next = new facet(2);
                                codim2Act = codim2Act->next;
                        }
                        intvec *n = new intvec(this->numVars);
                        makeInt(P,jj,*n);
                        codim2Act->setFacetNormal(n);
                        delete n;                                       
                }               
                /*We check whether the facet spanned by the codim-2 facets
                * intersects with the positive orthant. Otherwise we define this
                * facet to be non-flippable
                */
                intvec *iv_intPoint = new intvec(this->numVars);
                dd_MatrixPtr shiftMatrix;
                dd_MatrixPtr intPointMatrix;
                shiftMatrix = dd_CreateMatrix(this->numVars,this->numVars+1);
                for(int kk=0;kk<this->numVars;kk++)
                {
                        dd_set_si(shiftMatrix->matrix[kk][0],1);
                        dd_set_si(shiftMatrix->matrix[kk][kk+1],1);
                }
                intPointMatrix=dd_MatrixAppend(ddakt,shiftMatrix);              
                interiorPoint(intPointMatrix,*iv_intPoint);
                for(int ll=0;ll<this->numVars;ll++)
                {
                        if( (*iv_intPoint)[ll] < 0 )
                        {
                                fAct->isFlippable=FALSE;
                                break;
                        }
                }
                /*End of check*/                                        
                fAct = fAct->next;      
                dd_FreeMatrix(ddakt);
//              dd_FreeMatrix(ddineq);
                dd_FreeMatrix(shiftMatrix);
                dd_FreeMatrix(intPointMatrix);
                dd_FreePolyhedra(ddpolyh);
                delete iv_intPoint;
        }//for
        dd_FreeMatrix(ddineq);
}
                
/** \brief Compute the Groebner Basis on the other side of a shared facet 
 *
 * Implements algorithm 4.3.2 from Anders' thesis.
 * As shown there it is not necessary to compute an interior point. The knowledge of the facet normal
 * suffices. A term \f$ x^\gamma \f$ of \f$ g \f$ is in \f$  in_\omega(g) \f$ iff \f$ \gamma - leadexp(g)\f$
 * is parallel to \f$ leadexp(g) \f$
 * Parallelity is checked using basic linear algebra. See gcone::isParallel.
 * Other possibilities include computing the rank of the matrix consisting of the vectors in question and
 * computing an interior point of the facet and taking all terms having the same weight with respect 
 * to this interior point.
 *\param ideal, facet
 * Input: a marked,reduced Groebner basis and a facet
 */
void gcone::flip(ideal gb, facet *f)            //Compute "the other side"
{                       
        intvec *fNormal = new intvec(this->numVars);    //facet normal, check for parallelity                   
        fNormal = f->getFacetNormal();  //read this->fNormal;

        std::cout << "running gcone::flip" << std::endl;
        std::cout << "flipping UCN " << this->getUCN() << endl;
        cout << "over facet (";
        fNormal->show(1,0);
        cout << ") with UCN " << f->getUCN();
        std::cout << std::endl;

        /*1st step: Compute the initial ideal*/
        /*poly initialFormElement[IDELEMS(gb)];*/       //array of #polys in GB to store initial form
        ideal initialForm=idInit(IDELEMS(gb),this->gcBasis->rank);
        poly aktpoly;   
        computeInv(gb,initialForm,*fNormal);
        //NOTE The code below went into gcone::computeInv
#ifdef gfan_DEBUG
/*      cout << "Initial ideal is: " << endl;
        idShow(initialForm);
        //f->printFlipGB();*/
//      cout << "===" << endl;
#endif                  
        /*2nd step: lift initial ideal to a GB of the neighbouring cone using minus alpha as weight*/
        /*Substep 2.1
        compute $G_{-\alpha}(in_v(I)) 
        see journal p. 66
        NOTE Check for different rings. Prolly it will not always be necessary to add a weight, if the
        srcRing already has a weighted ordering
        */
        ring srcRing=currRing;
        ring tmpRing;
                        
        if( (srcRing->order[0]!=ringorder_a))
        {
                tmpRing=rCopyAndAddWeight(srcRing,ivNeg(fNormal));
        }
        else
        {
                tmpRing=rCopy0(srcRing);
                int length=fNormal->length();
                int *A=(int *)omAlloc0(length*sizeof(int));
                for(int jj=0;jj<length;jj++)
                {
                        A[jj]=-(*fNormal)[jj];
                }
                omFree(tmpRing->wvhdl[0]);
                tmpRing->wvhdl[0]=(int*)A;
                tmpRing->block1[0]=length;
                rComplete(tmpRing);     
        }
        delete fNormal; //NOTE: Why does this crash?
        rChangeCurrRing(tmpRing);
                        
        //rWrite(currRing); cout << endl;
                        
        ideal ina;                      
        ina=idrCopyR(initialForm,srcRing);
#ifndef NDEBUG                  
#ifdef gfan_DEBUG
        cout << "ina=";
        idShow(ina); cout << endl;
#endif
#endif
        ideal H;
        //H=kStd(ina,NULL,isHomog,NULL);        //we know it is homogeneous
        H=kStd(ina,NULL,testHomog,NULL);        //This is \mathcal(G)_{>_-\alpha}(in_v(I))
        idSkipZeroes(H);
#ifndef NDEBUG
#ifdef gfan_DEBUG
                        cout << "H="; idShow(H); cout << endl;
#endif
#endif
        /*Substep 2.2
        do the lifting and mark according to H
        */
        rChangeCurrRing(srcRing);
        ideal srcRing_H;
        ideal srcRing_HH;                       
        srcRing_H=idrCopyR(H,tmpRing);
#ifndef NDEBUG
#ifdef gfan_DEBUG
        cout << "srcRing_H = ";
        idShow(srcRing_H); cout << endl;
#endif
#endif
        srcRing_HH=ffG(srcRing_H,this->gcBasis);        
#ifndef NDEBUG
#ifdef gfan_DEBUG
        cout << "srcRing_HH = ";
        idShow(srcRing_HH); cout << endl;
#endif
#endif
        /*Substep 2.2.1
         * Mark according to G_-\alpha
         * Here we have a minimal basis srcRing_HH. In order to turn this basis into a reduced basis
         * we have to compute an interior point of C(srcRing_HH). For this we need to know the cone
         * represented by srcRing_HH MARKED ACCORDING TO G_{-\alpha}
         * Thus we check whether the leading monomials of srcRing_HH and srcRing_H coincide. If not we 
         * compute the difference accordingly
        */
        dd_set_global_constants();
        bool markingsAreCorrect=FALSE;
        dd_MatrixPtr intPointMatrix;
        int iPMatrixRows=0;
        dd_rowrange aktrow=0;                   
        for (int ii=0;ii<IDELEMS(srcRing_HH);ii++)
        {
                poly aktpoly=(poly)srcRing_HH->m[ii];
                iPMatrixRows = iPMatrixRows+pLength(aktpoly);
        }
        /* additionally one row for the standard-simplex and another for a row that becomes 0 during
         * construction of the differences
         */
        intPointMatrix = dd_CreateMatrix(iPMatrixRows+2,this->numVars+1); //iPMatrixRows+10;
        intPointMatrix->numbtype=dd_Integer;    //NOTE: DO NOT REMOVE OR CHANGE TO dd_Rational
        
        for (int ii=0;ii<IDELEMS(srcRing_HH);ii++)
        {
                markingsAreCorrect=FALSE;       //crucial to initialise here
                poly aktpoly=srcRing_HH->m[ii];
                /*Comparison of leading monomials is done via exponent vectors*/
                for (int jj=0;jj<IDELEMS(H);jj++)
                {
                        int *src_ExpV = (int *)omAlloc((this->numVars+1)*sizeof(int));
                        int *dst_ExpV = (int *)omAlloc((this->numVars+1)*sizeof(int));
                        pGetExpV(aktpoly,src_ExpV);
                        rChangeCurrRing(tmpRing);       //this ring change is crucial!
                        pGetExpV(pCopy(H->m[ii]),dst_ExpV);
                        rChangeCurrRing(srcRing);
                        bool expVAreEqual=TRUE;
                        for (int kk=1;kk<=this->numVars;kk++)
                        {
#ifdef gfan_DEBUG
//                                              cout << src_ExpV[kk] << "," << dst_ExpV[kk] << endl;
#endif
                                if (src_ExpV[kk]!=dst_ExpV[kk])
                                {
                                        expVAreEqual=FALSE;
                                }
                        }                                       
                                        //if (*src_ExpV == *dst_ExpV)
                        if (expVAreEqual==TRUE)
                        {
                                markingsAreCorrect=TRUE; //everything is fine
#ifdef gfan_DEBUG
//                              cout << "correct markings" << endl;
#endif
                        }//if (pHead(aktpoly)==pHead(H->m[jj])
                        omFree(src_ExpV);
                        omFree(dst_ExpV);
                }//for (int jj=0;jj<IDELEMS(H);jj++)
                                
                int *v=(int *)omAlloc((this->numVars+1)*sizeof(int));
                int *leadExpV=(int *)omAlloc((this->numVars+1)*sizeof(int));
                if (markingsAreCorrect==TRUE)
                {
                        pGetExpV(aktpoly,leadExpV);
                }
                else
                {
                        rChangeCurrRing(tmpRing);
                        pGetExpV(pHead(H->m[ii]),leadExpV); //We use H->m[ii] as leading monomial
                        rChangeCurrRing(srcRing);
                }
                /*compute differences of the expvects*/                         
                while (pNext(aktpoly)!=NULL)
                {
                        /*The following if-else-block makes sure the first term (i.e. the wrongly marked term) 
                        is not omitted when computing the differences*/
                        if(markingsAreCorrect==TRUE)
                        {
                                aktpoly=pNext(aktpoly);
                                pGetExpV(aktpoly,v);
                        }
                        else
                        {
                                pGetExpV(pHead(aktpoly),v);
                                markingsAreCorrect=TRUE;
                        }

                        for (int jj=0;jj<this->numVars;jj++)
                        {                               
                                /*Store into ddMatrix*/                                                         
                                dd_set_si(intPointMatrix->matrix[aktrow][jj+1],leadExpV[jj+1]-v[jj+1]);
                        }
                        aktrow +=1;
                }
                omFree(v);
                omFree(leadExpV);
        }//for (int ii=0;ii<IDELEMS(srcRing_HH);ii++)
        /*Now we add the constraint for the standard simplex*/
        /*NOTE:Might actually work without the standard simplex
        * No, it won't. MM 
        */
        dd_set_si(intPointMatrix->matrix[aktrow][0],-1);
        for (int jj=1;jj<=this->numVars;jj++)
        {
                dd_set_si(intPointMatrix->matrix[aktrow][jj],1);
        }
        //Let's make sure we compute interior points from the positive orthant
        dd_MatrixPtr posRestr=dd_CreateMatrix(this->numVars,this->numVars+1);
        int jj=1;
        for (int ii=0;ii<this->numVars;ii++)
        {
                dd_set_si(posRestr->matrix[ii][jj],1);
                jj++;                                                   
        }
        dd_MatrixAppendTo(&intPointMatrix,posRestr);
        dd_FreeMatrix(posRestr);
#ifdef gfan_DEBUG
//                      dd_WriteMatrix(stdout,intPointMatrix);
#endif
        intvec *iv_weight = new intvec(this->numVars);
        interiorPoint(intPointMatrix, *iv_weight);      //iv_weight now contains the interior point
        dd_FreeMatrix(intPointMatrix);
        dd_free_global_constants();
                        
        /*Step 3
        turn the minimal basis into a reduced one
        */
        //ring dstRing=rCopyAndAddWeight(tmpRing,iv_weight);    
                        
        // NOTE May assume that at this point srcRing already has 3 blocks of orderins, starting with a
        // Thus: 
        //ring dstRing=rCopyAndChangeWeight(srcRing,iv_weight); 
        ring dstRing=rCopy0(tmpRing);
        int length=iv_weight->length();
        int *A=(int *)omAlloc0(length*sizeof(int));
        for(int jj=0;jj<length;jj++)
        {
                A[jj]=(*iv_weight)[jj];
        }
        dstRing->wvhdl[0]=(int*)A;
        rComplete(dstRing);                                     
        rChangeCurrRing(dstRing);
        //rDelete(tmpRing);
        delete iv_weight;

        //rWrite(dstRing); cout << endl;

        ideal dstRing_I;                        
        dstRing_I=idrCopyR(srcRing_HH,srcRing);
        //dstRing_I=idrCopyR(inputIdeal,srcRing);
        //validOpts<1>=TRUE;
#ifdef gfan_DEBUG
        //idShow(dstRing_I);
#endif                  
        BITSET save=test;
        test|=Sy_bit(OPT_REDSB);
        test|=Sy_bit(OPT_REDTAIL);
#ifdef gfan_DEBUG
        test|=Sy_bit(6);        //OPT_DEBUG
#endif
        ideal tmpI;
        //NOTE Any of the two variants of tmpI={idrCopy(),dstRing_I} does the trick
        //tmpI = idrCopyR(this->inputIdeal,this->baseRing);
        tmpI = dstRing_I;
        dstRing_I=kStd(tmpI,NULL,testHomog,NULL);
        idNorm(dstRing_I);                      
                        //kInterRed(dstRing_I);
        idSkipZeroes(dstRing_I);
        test=save;
        /*End of step 3 - reduction*/
                        
        f->setFlipGB(dstRing_I);//store the flipped GB
        f->flipRing=rCopy(dstRing);     //store the ring on the other side
//#ifdef gfan_DEBUG
        cout << "Flipped GB is UCN " << counter+1 << ":" << endl;
//      this->idDebugPrint(dstRing_I);
//      cout << endl;
//#endif                        
        rChangeCurrRing(srcRing);       //return to the ring we started the computation of flipGB in
//      rDelete(dstRing);
}//void flip(ideal gb, facet *f)

/** \brief Compute initial ideal
 * Compute the initial ideal in_v(G) wrt a (possible) facet normal
 * used in gcone::getFacetNormal in order to preprocess possible facet normals
 * and in gcone::flip for obvious reasons.
*/
void gcone::computeInv(ideal &gb, ideal &initialForm, intvec &fNormal)
{
        intvec *check = new intvec(this->numVars);
        poly initialFormElement[IDELEMS(gb)];
        poly aktpoly;
        
        for (int ii=0;ii<IDELEMS(gb);ii++)
        {
                aktpoly = (poly)gb->m[ii];                                                              
                int *v=(int *)omAlloc((this->numVars+1)*sizeof(int));
                int *leadExpV=(int *)omAlloc((this->numVars+1)*sizeof(int));
                pGetExpV(aktpoly,leadExpV);     //find the leading exponent in leadExpV[1],...,leadExpV[n], use pNext(p)
                initialFormElement[ii]=pHead(aktpoly);
                                
                while(pNext(aktpoly)!=NULL)     /*loop trough terms and check for parallelity*/
                {
                        aktpoly=pNext(aktpoly); //next term
                        pSetm(aktpoly);
                        pGetExpV(aktpoly,v);            
                        /* Convert (int)v into (intvec)check */                 
                        for (int jj=0;jj<this->numVars;jj++)
                        {
                                                //cout << "v["<<jj+1<<"]="<<v[jj+1]<<endl;
                                                //cout << "leadExpV["<<jj+1<<"]="<<leadExpV[jj+1]<<endl;
                                (*check)[jj]=v[jj+1]-leadExpV[jj+1];
                        }
#ifdef gfan_DEBUG
//                      cout << "check=";                       
//                      check->show();
//                      cout << endl;
#endif
                        if (isParallel(*check,fNormal)) //pass *check when 
                        {
//                              cout << "Parallel vector found, adding to initialFormElement" << endl;                  
                                initialFormElement[ii] = pAdd(pCopy(initialFormElement[ii]),(poly)pHead(aktpoly));
                        }                                               
                }//while
#ifdef gfan_DEBUG
//              cout << "Initial Form=";                                
//              pWrite(initialFormElement[ii]);
//              cout << "---" << endl;
#endif
                /*Now initialFormElement must be added to (ideal)initialForm */
                initialForm->m[ii]=initialFormElement[ii];
                omFree(leadExpV);
                omFree(v);              
        }//for
        delete check;
}

/** \brief Compute the remainder of a polynomial by a given ideal
 *
 * Compute \f$ f^{\mathcal{G}} \f$
 * Algorithm is taken from Cox, Little, O'Shea, IVA 2nd Ed. p 62
 * However, since we are only interested in the remainder, there is no need to
 * compute the factors \f$ a_i \f$
 */
//NOTE: Should be replaced by kNF or kNF2
//NOTE: Done
//NOTE: removed with r12286
                
/** \brief Compute \f$ f-f^{\mathcal{G}} \f$
*/
//NOTE: use kNF or kNF2 instead of restOfDivision
ideal gcone::ffG(ideal const &H, ideal const &G)
{
//                      cout << "Entering ffG" << endl;
        int size=IDELEMS(H);
        ideal res=idInit(size,1);
        poly temp1, temp2, temp3;       //polys to temporarily store values for pSub
        for (int ii=0;ii<size;ii++)
        {
//              res->m[ii]=restOfDiv(H->m[ii],G);
                res->m[ii]=kNF(G, NULL,H->m[ii],0,0);
                temp1=H->m[ii];
                temp2=res->m[ii];
                temp3=pSub(temp1, temp2);
                res->m[ii]=temp3;
                //res->m[ii]=pSub(temp1,temp2); //buggy
                //pSort(res->m[ii]);
                //pSetm(res->m[ii]);
                //cout << "res->m["<<ii<<"]=";pWrite(res->m[ii]);       
        }                       
        return res;
}
                
/** \brief Compute a Groebner Basis
 *
 * Computes the Groebner basis and stores the result in gcone::gcBasis
 *\param ideal
 *\return void
 */
void gcone::getGB(ideal const &inputIdeal)              
{
        BITSET save=test;
        test|=Sy_bit(OPT_REDSB);
        test|=Sy_bit(OPT_REDTAIL);
        ideal gb;
        gb=kStd(inputIdeal,NULL,testHomog,NULL);
        idNorm(gb);
        idSkipZeroes(gb);
        this->gcBasis=gb;       //write the GB into gcBasis
        test=save;
}//void getGB
                
/** \brief Compute the negative of a given intvec
        */              
intvec *gcone::ivNeg(const intvec *iv)
{
        //NOTE: Can't this be done without new?
        intvec *res = new intvec(iv->length());
        res=ivCopy(iv);
        *res *= (int)-1;                                                
        return res;
}


/** \brief Compute the dot product of two intvecs
*
*/
int gcone::dotProduct(intvec const &iva, intvec const &ivb)                             
{                       
        int res=0;
        for (int i=0;i<this->numVars;i++)
        {
                res = res+(iva[i]*ivb[i]);
        }
        return res;
}//int dotProduct

/** \brief Check whether two intvecs are parallel
 *
 * \f$ \alpha\parallel\beta\Leftrightarrow\langle\alpha,\beta\rangle^2=\langle\alpha,\alpha\rangle\langle\beta,\beta\rangle \f$
 */
bool gcone::isParallel(intvec const &a, intvec const &b)
{                       
        int lhs,rhs;
        bool res;
        lhs=dotProduct(a,b)*dotProduct(a,b);
        rhs=dotProduct(a,a)*dotProduct(b,b);
                        //cout << "LHS="<<lhs<<", RHS="<<rhs<<endl;
        if (lhs==rhs)
        {
                res = TRUE;
        }
        else
        {
                res = FALSE;
        }
        return res;
}//bool isParallel
                
/** \brief Compute an interior point of a given cone
 * Result will be written into intvec iv. 
 * Any rational point is automatically converted into an integer.
 */
void gcone::interiorPoint(dd_MatrixPtr const &M, intvec &iv) //no const &M here since we want to remove redundant rows
{
        dd_LPPtr lp,lpInt;
        dd_ErrorType err=dd_NoError;
        dd_LPSolverType solver=dd_DualSimplex;
        dd_LPSolutionPtr lpSol=NULL;
        dd_rowset ddlinset,ddredrows;   //needed for dd_FindRelativeInterior
        dd_rowindex ddnewpos;
        dd_NumberType numb;     
                        //M->representation=dd_Inequality;
                        //M->objective-dd_LPMin;  //Not sure whether this is needed
                        
                        //NOTE: Make this n-dimensional!
                        //dd_set_si(M->rowvec[0],1);dd_set_si(M->rowvec[1],1);dd_set_si(M->rowvec[2],1);
                                                                        
                        /*NOTE: Leave the following line commented out!
        * Otherwise it will cause interior points that are not strictly positive on some examples
        * 
                        */
                        //dd_MatrixCanonicalize(&M, &ddlinset, &ddredrows, &ddnewpos, &err);
                        //if (err!=dd_NoError){cout << "Error during dd_MatrixCanonicalize" << endl;}
                        //cout << "Tick 2" << endl;
                        //dd_WriteMatrix(stdout,M);
                        
        lp=dd_Matrix2LP(M, &err);
        if (err!=dd_NoError){cout << "Error during dd_Matrix2LP in gcone::interiorPoint" << endl;}                      
        if (lp==NULL){cout << "LP is NULL" << endl;}
#ifdef gfan_DEBUG
//                      dd_WriteLP(stdout,lp);
#endif  
                                        
        lpInt=dd_MakeLPforInteriorFinding(lp);
        if (err!=dd_NoError){cout << "Error during dd_MakeLPForInteriorFinding in gcone::interiorPoint" << endl;}
#ifdef gfan_DEBUG
//                      dd_WriteLP(stdout,lpInt);
#endif                  

        dd_FindRelativeInterior(M,&ddlinset,&ddredrows,&lpSol,&err);
        if (err!=dd_NoError)
        {
                cout << "Error during dd_FindRelativeInterior in gcone::interiorPoint" << endl;
                dd_WriteErrorMessages(stdout, err);
        }
                        
                        //dd_LPSolve(lpInt,solver,&err);        //This will not result in a point from the relative interior
        if (err!=dd_NoError){cout << "Error during dd_LPSolve" << endl;}
                                                                        
                        //lpSol=dd_CopyLPSolution(lpInt);
        if (err!=dd_NoError){cout << "Error during dd_CopyLPSolution" << endl;}                 
#ifdef gfan_DEBUG
        cout << "Interior point: ";
        for (int ii=1; ii<(lpSol->d)-1;ii++)
        {
                dd_WriteNumber(stdout,lpSol->sol[ii]);
        }
        cout << endl;
#endif
                        
        //NOTE The following strongly resembles parts of makeInt. 
        //Maybe merge sometimes
        mpz_t kgV; mpz_init(kgV);
        mpz_set_str(kgV,"1",10);
        mpz_t den; mpz_init(den);
        mpz_t tmp; mpz_init(tmp);
        mpq_get_den(tmp,lpSol->sol[1]);
        for (int ii=1;ii<(lpSol->d)-1;ii++)
        {
                mpq_get_den(den,lpSol->sol[ii+1]);
                mpz_lcm(kgV,tmp,den);
                mpz_set(tmp, kgV);
        }
        mpq_t qkgV;
        mpq_init(qkgV);
        mpq_set_z(qkgV,kgV);
        for (int ii=1;ii<(lpSol->d)-1;ii++)
        {
                mpq_t product;
                mpq_init(product);
                mpq_mul(product,qkgV,lpSol->sol[ii]);
                iv[ii-1]=(int)mpz_get_d(mpq_numref(product));
                mpq_clear(product);
        }
#ifdef gfan_DEBUG
//                      iv.show();
//                      cout << endl;
#endif
        mpq_clear(qkgV);
        mpz_clear(tmp);
        mpz_clear(den);
        mpz_clear(kgV);                 
                        
        dd_FreeLPSolution(lpSol);
        dd_FreeLPData(lpInt);
        dd_FreeLPData(lp);
        set_free(ddlinset);
        set_free(ddredrows);                    
                        
}//void interiorPoint(dd_MatrixPtr const &M)
                
/** \brief Copy a ring and add a weighted ordering in first place
 * 
 */
ring gcone::rCopyAndAddWeight(ring const &r, intvec const *ivw)                         
{
        ring res=rCopy0(r);
        int jj;
                        
        omFree(res->order);
        res->order =(int *)omAlloc0(4*sizeof(int));
        omFree(res->block0);
        res->block0=(int *)omAlloc0(4*sizeof(int));
        omFree(res->block1);
        res->block1=(int *)omAlloc0(4*sizeof(int));
        omfree(res->wvhdl);
        res->wvhdl =(int **)omAlloc0(4*sizeof(int**));
                        
        res->order[0]=ringorder_a;
        res->block0[0]=1;
        res->block1[0]=res->N;;
        res->order[1]=ringorder_dp;     //basically useless, since that should never be used                    
        res->block0[1]=1;
        res->block1[1]=res->N;;
        res->order[2]=ringorder_C;

        int length=ivw->length();
        int *A=(int *)omAlloc0(length*sizeof(int));
        for (jj=0;jj<length;jj++)
        {                               
                A[jj]=(*ivw)[jj];                               
        }                       
        res->wvhdl[0]=(int *)A;
        res->block1[0]=length;
                        
        rComplete(res);
        return res;
}//rCopyAndAdd
                
ring rCopyAndChangeWeight(ring const &r, intvec *ivw)
{
        ring res=rCopy0(currRing);
        rComplete(res);
        rSetWeightVec(res,(int64*)ivw);
        //rChangeCurrRing(rnew);
        return res;
}
                
/** \brief Checks whether a given facet is a search facet
 * Determines whether a given facet of a cone is the search facet of a neighbouring cone
 * This is done in the following way:
 * We loop through all facets of the cone and find the "smallest" facet, i.e. the unique facet
 * that is first crossed during the generic walk.
 * We then check whether the fNormal of this facet is parallel to the fNormal of our testfacet.
 * If this is the case, then our facet is indeed a search facet and TRUE is retuned. 
*/
//removed with r12286
                
/** \brief Check for equality of two intvecs
 */
bool gcone::areEqual(intvec const &a, intvec const &b)
{
        bool res=TRUE;
        for(int ii=0;ii<this->numVars;ii++)
        {
                if(a[ii]!=b[ii])
                {
                        res=FALSE;
                        break;
                }
        }
        return res;
}
                
/** \brief The reverse search algorithm
 */
//removed with r12286
                
/** \brief The new method of Markwig and Jensen
 * Compute gcBasis and facets for the arbitrary starting cone. Store \f$(codim-1)\f$-facets as normals.
 * In order to represent a facet uniquely compute also the \f$(codim-2)\f$-facets and norm by the gcd of the components.
 * Keep a list of facets as a linked list containing an intvec and an integer matrix.
 * Since a \f$(codim-1)\f$-facet belongs to exactly two full dimensional cones, we remove a facet from the list as
 * soon as we compute this facet again. Comparison of facets is done by...
 */
void gcone::noRevS(gcone &gcRoot, bool usingIntPoint)
{       
        facet *SearchListRoot = new facet(); //The list containing ALL facets we come across
        facet *SearchListAct;
        SearchListAct = NULL;
        //SearchListAct = SearchListRoot;
                        
        gcone *gcAct;
        gcAct = &gcRoot;
        gcone *gcPtr;   //Pointer to end of linked list of cones
        gcPtr = &gcRoot;
        gcone *gcNext;  //Pointer to next cone to be visited
        gcNext = &gcRoot;
        gcone *gcHead;
        gcHead = &gcRoot;
                        
        facet *fAct;
        fAct = gcAct->facetPtr;                 
                        
        ring rAct;
        rAct = currRing;
                                                
        int UCNcounter=gcAct->getUCN();
        
        /* Use pure SLA or writeCone2File */
//      enum heuristic {
//              ram,
//              hdd
//      };
//      heuristic h;
//      h=hdd;
        
#ifdef gfan_DEBUG
        cout << "NoRevs" << endl;
        cout << "Facets are:" << endl;
        gcAct->showFacets();
#endif                  
                        
        gcAct->getCodim2Normals(*gcAct);
                                
        //Compute unique representation of codim-2-facets
        gcAct->normalize();
                        
        /* Make a copy of the facet list of first cone
           Since the operations getCodim2Normals and normalize affect the facets
           we must not memcpy them before these ops!
        */
        intvec *fNormal;// = new intvec(this->numVars);
        intvec *f2Normal;// = new intvec(this->numVars);
        facet *codim2Act; codim2Act = NULL;                     
        facet *sl2Root; //sl2Root = new facet(2);
        facet *sl2Act;  //sl2Act = sl2Root;
                        
        for(int ii=0;ii<this->numFacets;ii++)
        {
                //only copy flippable facets! NOTE: We do not need flipRing or any such information.
                if(fAct->isFlippable==TRUE)
                {
                        fNormal = fAct->getFacetNormal();
                        if( ii==0 || (ii>0 && SearchListAct==NULL) ) //1st facet may be non-flippable
                        {                                               
                                SearchListAct = SearchListRoot;
                                                //memcpy(SearchListAct,fAct,sizeof(facet));                                     
                        }
                        else
                        {                       
                                SearchListAct->next = new facet();
                                SearchListAct = SearchListAct->next;                                            
                                                //memcpy(SearchListAct,fAct,sizeof(facet));                             
                        }
                        SearchListAct->setFacetNormal(fNormal);
                        SearchListAct->setUCN(this->getUCN());
                        SearchListAct->numCodim2Facets=fAct->numCodim2Facets;
                        SearchListAct->isFlippable=TRUE;
                                        //Copy codim2-facets                            
                        codim2Act=fAct->codim2Ptr;
                        SearchListAct->codim2Ptr = new facet(2);
                        sl2Root = SearchListAct->codim2Ptr;
                        sl2Act = sl2Root;
                                        //while(codim2Act!=NULL)
                        for(int jj=0;jj<fAct->numCodim2Facets;jj++)
                        {
                                f2Normal = codim2Act->getFacetNormal();
                                if(jj==0)
                                {                                               
                                        sl2Act = sl2Root;
                                        sl2Act->setFacetNormal(f2Normal);
                                }
                                else
                                {
                                        sl2Act->next = new facet(2);
                                        sl2Act = sl2Act->next;
                                        sl2Act->setFacetNormal(f2Normal);
                                }                                       
                                codim2Act = codim2Act->next;
                        }
                        fAct = fAct->next;
                }//if(fAct->isFlippable==TRUE)
                else {fAct = fAct->next;}
        }//End of copying facets into SLA
        
        SearchListAct = SearchListRoot; //Set to beginning of list
        /*Make SearchList doubly linked*/
        while(SearchListAct!=NULL)
        {
                if(SearchListAct->next!=NULL)
                {
                        SearchListAct->next->prev = SearchListAct;                                      
                }
                SearchListAct = SearchListAct->next;
        }
        SearchListAct = SearchListRoot; //Set to beginning of List
        
        fAct = gcAct->facetPtr;
        //NOTE Disabled until code works as expected. Reenabled 2.11.2009
        gcAct->writeConeToFile(*gcAct);
                        
        /*End of initialisation*/
        fAct = SearchListAct;
        /*2nd step
          Choose a facet from fListPtr, flip it and forget the previous cone
          We always choose the first facet from fListPtr as facet to be flipped
        */                      
//      time_t tic, tac;
        while((SearchListAct!=NULL))// && counter<10)
        {//NOTE See to it that the cone is only changed after ALL facets have been flipped!                             
                fAct = SearchListAct;
                                
                while(fAct!=NULL)
                {       //Since SLA should only contain flippables there should be no need to check for that
                        
                        gcAct->flip(gcAct->gcBasis,fAct);
                        
                        
                        ring rTmp=rCopy(fAct->flipRing);
                        rComplete(rTmp);                        
                        rChangeCurrRing(rTmp);
                        gcone *gcTmp = new gcone::gcone(*gcAct,*fAct);//copy constructor!
                        /* Now gcTmp->gcBasis and gcTmp->baseRing are set from fAct->flipGB and fAct->flipRing.
                         * Since we come at most once across a given facet from gcAct->facetPtr we can delete them.
                         * NOTE: Can this cause trouble with the destructor?
                         * Answer: Yes it bloody well does!
                         * However I'd like to delete this data here, since if we have a cone with many many facets it
                         * should pay to get rid of the flipGB as soon as possible.
                         * Destructor must be equipped with necessary checks.
                        */
//                      idDelete((ideal *)&fAct->flipGB);
//                      rDelete(fAct->flipRing);
                        
                        gcTmp->getConeNormals(gcTmp->gcBasis, FALSE);   
                        gcTmp->getCodim2Normals(*gcTmp);
                        gcTmp->normalize();
#ifdef gfan_DEBUG
                        gcTmp->showFacets(1);
#endif
                        if(gfanHeuristic==1)
                        {
                                gcTmp->writeConeToFile(*gcTmp);
                        }
                        /*add facets to SLA here*/
                        SearchListRoot=gcTmp->enqueueNewFacets(*SearchListRoot);
#ifdef gfan_DEBUG
                        if(SearchListRoot!=NULL)
                                gcTmp->showSLA(*SearchListRoot);
#endif
                        rChangeCurrRing(gcAct->baseRing);
                        //rDelete(rTmp);
                        //doubly linked for easier removal
                        gcTmp->prev = gcPtr;
                        gcPtr->next=gcTmp;
                        gcPtr=gcPtr->next;
                        if(fAct->getUCN() == fAct->next->getUCN())
                        {
                                fAct=fAct->next;
                        }
                        else
                                break;
                }//while( ( (fAct->next!=NULL) && (fAct->getUCN()==fAct->next->getUCN() ) ) );
                //NOTE Now all neighbouring cones of gcAct have been computed, so we may delete gcAct
                gcone *deleteMarker;
                deleteMarker=gcAct;             
//              delete deleteMarker;
//              deleteMarker=NULL;
                //Search for cone with smallest UCN
                gcNext = gcHead;
                while(gcNext!=NULL && SearchListRoot!=NULL && gcNext!=(gcone * const)0xfbfbfbfbfbfbfbfb && gcNext!=(gcone * const)0xfbfbfbfb)
                {                       
                        /*NOTE if gcNext->getUCN is smaller than SearchListRoot->getUCN it follows, that the cone
                        gcNext will not be used in any more computation. So -> delete
                        */
                        if (gcNext->getUCN() < SearchListRoot->getUCN() )
                        {
                                //idDelete((ideal *)&gcNext->gcBasis);  //at least drop huge gröbner bases
                                if(gcNext == gcHead)
                                {
                                        deleteMarker = gcHead;
                                        gcHead = gcNext->next;
                                        //gcNext->next->prev = NULL;
                                }
                                else
                                {
                                        deleteMarker = gcNext;
                                        gcNext->prev->next = gcNext->next;
                                        gcNext->next->prev = gcNext->prev;
                                }
//                              gcNext = gcNext->next;
//                              delete deleteMarker;
//                              deleteMarker = NULL;
                        }
                        else if( gcNext->getUCN() == SearchListRoot->getUCN() )
                        {//NOTE: Implement heuristic to be used!
                                if(gfanHeuristic==0)
                                {
                                        gcAct = gcNext;
                                        rAct=rCopy(gcAct->baseRing);
                                        rComplete(rAct);
                                        rChangeCurrRing(rAct);                                          
                                        break;
                                }
                                else if(gfanHeuristic==1)
                                {
                                        //Read st00f from file
                                        gcAct = gcNext;
                                        //implant the GB into gcAct
                                        readConeFromFile(gcNext->getUCN(), gcAct);
                                        rAct=rCopy(gcAct->baseRing);
                                        rComplete(rAct);
                                        rChangeCurrRing(rAct);
                                        break;
                                }                               
                        }                       
                        gcNext = gcNext->next;
//                      if(deleteMarker!=NULL && deleteMarker!=(gcone *)0xfbfbfbfbfbfbfbfb)
                        if(this->getUCN()!=1)   //workaround to avoid unpredictable behaviour towards end of program
                                delete deleteMarker;
//                      deleteMarker = NULL;
//                      gcNext = gcNext->next;
                }
                UCNcounter++;
                                //SearchListAct = SearchListAct->next;
                                //SearchListAct = fAct->next;
                SearchListAct = SearchListRoot;
        }
        cout << endl << "Found " << counter << " cones - terminating" << endl;
                
                        //NOTE Hm, comment in and get a crash for free...
                        //dd_free_global_constants();                           
                        //gc.writeConeToFile(gc);
                        
                        
                        //fAct = fListPtr;
                        //gcone *gcTmp = new gcone(gc); //copy
                        //gcTmp->flip(gcTmp->gcBasis,fAct);
                        //NOTE: gcTmp may be deleted, gcRoot from main proc should probably not!
                        
}//void noRevS(gcone &gc)       
                
                
/** \brief Make a set of rational vectors into integers
 *
 * We compute the lcm of the denominators and multiply with this to get integer values.         
 * \param dd_MatrixPtr,intvec
 */
void gcone::makeInt(dd_MatrixPtr const &M, int const line, intvec &n)
{                       
        mpz_t denom[this->numVars];
        for(int ii=0;ii<this->numVars;ii++)
        {
                mpz_init_set_str(denom[ii],"0",10);
        }
                
        mpz_t kgV,tmp;
        mpz_init(kgV);
        mpz_init(tmp);
                        
        for (int ii=0;ii<(M->colsize)-1;ii++)
        {
                mpz_t z;
                mpz_init(z);
                mpq_get_den(z,M->matrix[line-1][ii+1]);
                mpz_set( denom[ii], z);
                mpz_clear(z);                           
        }
                                                
        /*Compute lcm of the denominators*/
        mpz_set(tmp,denom[0]);
        for (int ii=0;ii<(M->colsize)-1;ii++)
        {
                mpz_lcm(kgV,tmp,denom[ii]);
                mpz_set(tmp,kgV);                               
        }
                        
        /*Multiply the nominators by kgV*/
        mpq_t qkgV,res;
        mpq_init(qkgV);
        mpq_set_str(qkgV,"1",10);
        mpq_canonicalize(qkgV);
                        
        mpq_init(res);
        mpq_set_str(res,"1",10);
        mpq_canonicalize(res);
                        
        mpq_set_num(qkgV,kgV);
                        
//                      mpq_canonicalize(qkgV);
        for (int ii=0;ii<(M->colsize)-1;ii++)
        {
                mpq_mul(res,qkgV,M->matrix[line-1][ii+1]);
                n[ii]=(int)mpz_get_d(mpq_numref(res));
        }
                        //mpz_clear(denom[this->numVars]);
        mpz_clear(kgV);
        mpq_clear(qkgV); mpq_clear(res);                        
                        
}
/**
 * For all codim-2-facets we compute the gcd of the components of the facet normal and 
 * divide it out. Thus we get a normalized representation of each
 * (codim-2)-facet normal, i.e. a primitive vector
 */
void gcone::normalize()
{
        int ggT=1;
        facet *fAct;
        facet *codim2Act;
        fAct = this->facetPtr;
        codim2Act = fAct->codim2Ptr;
        intvec *n = new intvec(this->numVars);
                        
                        //while(codim2Act->next!=NULL)
        while(fAct!=NULL)
        {
                while(codim2Act!=NULL)
                {                               
                        n=codim2Act->getFacetNormal();
                        for(int ii=0;ii<this->numVars;ii++)
                        {
                                ggT = intgcd(ggT,(*n)[ii]);
                        }
                        for(int ii=0;ii<this->numVars;ii++)
                        {
                                (*n)[ii] = ((*n)[ii])/ggT;
                        }
                        codim2Act->setFacetNormal(n);
                        codim2Act = codim2Act->next;                            
                }
                fAct = fAct->next;
        }
        delete n;
                                
}
/** \brief Enqueue new facets into the searchlist 
 * The searchlist (SLA for short) is implemented as a FIFO
 * Checks are done as follows:
 * 1) Check facet fAct against all facets in SLA for parallelity. If it is not parallel to any one add it.
 * 2) If it is parallel compare the codim2 facets. If they coincide the facets are equal and we delete the 
 *      facet from SLA and do not add fAct.
 * It may very well happen, that SLA=\f$ \emptyset \f$ but we do not have checked all fActs yet. In this case we
 * can be sure, that none of the facets that are still there already were in SLA once, so we just dump them into SLA.
 * Takes ptr to search list root
 * Returns a pointer to new first element of Searchlist
 */
                //void enqueueNewFacets(facet &f)
facet * gcone::enqueueNewFacets(facet &f)
{
        facet *slHead;
        slHead = &f;
        facet *slAct;   //called with f=SearchListRoot
        slAct = &f;
        facet *slEnd;   //Pointer to end of SLA
        slEnd = &f;
        facet *slEndStatic;     //marks the end before a new facet is added             
        facet *fAct;
        fAct = this->facetPtr;
        facet *codim2Act;
        codim2Act = this->facetPtr->codim2Ptr;
        facet *sl2Act;
        sl2Act = f.codim2Ptr;
        /** Pointer to a facet that will be deleted */
        facet *deleteMarker;
        deleteMarker = NULL;
                        
        /** Flag to indicate a facet that should be added to SLA*/
        bool doNotAdd=FALSE;
        /** \brief  Flag to mark a facet that might be added
         * The following case may occur:
         * A facet fAct is found to be parallel but not equal to the current facet slAct from SLA.
         * This does however not mean that there does not exist a facet behind the current slAct that is actually equal
         * to fAct. In this case we set the boolean flag maybe to TRUE. If we encounter an equality lateron, it is reset to
         * FALSE and the according slAct is deleted. 
         * If slAct->next==NULL AND maybe==TRUE we know, that fAct must be added
         */
        volatile bool maybe=FALSE;
        /**A facet was removed, lengthOfSearchlist-- thus we must not rely on 
         * if(notParallelCtr==lengthOfSearchList) but rather
         * if( (notParallelCtr==lengthOfSearchList && removalOccured==FALSE)
         */
        volatile bool removalOccured=FALSE;
        int ctr=0;      //encountered equalities in SLA
        int notParallelCtr=0;
        int lengthOfSearchList=1;
        while(slEnd->next!=NULL)
        {
                slEnd=slEnd->next;
                lengthOfSearchList++;
        }
        slEndStatic = slEnd;
        /*1st step: compare facetNormals*/
        intvec *fNormal=NULL; //= new intvec(this->numVars);
        intvec *f2Normal=NULL; //= new intvec(this->numVars);
        intvec *slNormal=NULL; //= new intvec(this->numVars);
        intvec *sl2Normal=NULL; //= new intvec(this->numVars);
                        
        while(fAct!=NULL)
        {                                               
                if(fAct->isFlippable==TRUE)
                {
                        maybe=FALSE;
                        doNotAdd=TRUE;
                        fNormal=fAct->getFacetNormal();
                        slAct = slHead;
                        notParallelCtr=0;
//                      delete deleteMarker;
//                      deleteMarker=NULL;
                        /*If slAct==NULL and fAct!=NULL 
                        we just copy all remaining facets into SLA*/
                        if(slAct==NULL)
                        {
                                facet *fCopy;
                                fCopy = fAct;
                                while(fCopy!=NULL)
                                {
                                        if(slAct==NULL)
                                        {
                                                slAct = new facet();
                                                slHead = slAct;                                                         
                                        }
                                        else
                                        {
                                                slAct->next = new facet();
                                                slAct = slAct->next;
                                        }                                                       
                                        slAct->setFacetNormal(fAct->getFacetNormal());
                                        slAct->setUCN(fAct->getUCN());
                                        slAct->isFlippable=fAct->isFlippable;
                                        facet *f2Copy;
                                        f2Copy = fCopy->codim2Ptr;
                                        sl2Act = slAct->codim2Ptr;
                                        while(f2Copy!=NULL)
                                        {
                                                if(sl2Act==NULL)
                                                {
                                                        sl2Act = new facet(2);
                                                        slAct->codim2Ptr = sl2Act;                                      
                                                }
                                                else
                                                {
                                                        facet *marker;
                                                        marker = sl2Act;
                                                        sl2Act->next = new facet(2);
                                                        sl2Act = sl2Act->next;
                                                        sl2Act->prev = marker;
                                                }
                                                sl2Act->setFacetNormal(f2Copy->getFacetNormal());
                                                sl2Act->setUCN(f2Copy->getUCN());
                                                f2Copy = f2Copy->next;
                                        }
                                        fCopy = fCopy->next;
                                }
                                break;
                        }
                        /*End of dumping into SLA*/
                        while(slAct!=NULL)
                                        //while(slAct!=slEndStatic->next)
                        {
//                              if(deleteMarker!=NULL)
//                              {
//                                      delete deleteMarker;
//                                      deleteMarker=NULL;
//                              }
                                removalOccured=FALSE;
                                slNormal = slAct->getFacetNormal();
#ifdef gfan_DEBUG
                                cout << "Checking facet (";
                                fNormal->show(1,1);
                                cout << ") against (";
                                slNormal->show(1,1);
                                cout << ")" << endl;
#endif
                                if(!isParallel(fNormal, slNormal))
                                {
                                        notParallelCtr++;
//                                                      slAct = slAct->next;
                                }
                                else    //fN and slN are parallel
                                {
                                        //We check whether the codim-2-facets coincide
                                        codim2Act = fAct->codim2Ptr;
                                        ctr=0;
                                        while(codim2Act!=NULL)
                                        {
                                                f2Normal = codim2Act->getFacetNormal();
                                                                //sl2Act = f.codim2Ptr;
                                                sl2Act = slAct->codim2Ptr;
                                                while(sl2Act!=NULL)
                                                {
                                                        sl2Normal = sl2Act->getFacetNormal();
                                                        if(areEqual(f2Normal, sl2Normal))
                                                                ctr++;
                                                        sl2Act = sl2Act->next;
                                                }//while(sl2Act!=NULL)
                                                codim2Act = codim2Act->next;
                                        }//while(codim2Act!=NULL)
                                        if(ctr==fAct->numCodim2Facets)  //facets ARE equal
                                        {
#ifdef gfan_DEBUG
                                                cout << "Removing facet (";
                                                slNormal->show(1,0);
                                                cout << ") from SLA:" << endl;
                                                fAct->fDebugPrint();
                                                slAct->fDebugPrint();
#endif
                                                removalOccured=TRUE;
                                                slAct->isFlippable=FALSE;
                                                doNotAdd=TRUE;
                                                maybe=FALSE;                                                            
                                                if(slAct==slHead)       //We want to delete the first element of SearchList
                                                {
                                                        deleteMarker = slHead;                          
                                                        slHead = slAct->next;                                           
                                                        if(slHead!=NULL)
                                                                slHead->prev = NULL;
                                                        /*delete deleteMarker*/;                                        
                                                                        //set a bool flag to mark slAct as to be deleted
                                                }//NOTE find a way to delete without affecting slAct = slAct->next
                                                else if(slAct==slEndStatic)
                                                {
                                                        deleteMarker = slAct;                                   
                                                        if(slEndStatic->next==NULL)
                                                        {                                                       
                                                                slEndStatic = slEndStatic->prev;
                                                                slEndStatic->next = NULL;
                                                                slEnd = slEndStatic;
                                                        }
                                                        else    //we already added a facet after slEndStatic
                                                        {
                                                                slEndStatic->prev->next = slEndStatic->next;
                                                                slEndStatic->next->prev = slEndStatic->prev;
                                                                slEndStatic = slEndStatic->prev;
                                                                                        //slEnd = slEndStatic;
                                                        }
                                                }                                                               
                                                else
                                                {
                                                        deleteMarker = slAct;
                                                        slAct->prev->next = slAct->next;
                                                        slAct->next->prev = slAct->prev;
                                                }
                                                                
                                                //update lengthOfSearchList                                     
                                                lengthOfSearchList--;
                                                //delete slAct;
                                                //slAct=NULL;
                                                //slAct = slAct->next; //not needed, since facets are equal
//                                              delete deleteMarker;
                                                //deleteMarker=NULL;
                                                //fAct = fAct->next;
                                                break;
                                        }//if(ctr==fAct->numCodim2Facets)
                                        else    //facets are parallel but NOT equal. But this does not imply that there
                                                //is no other facet later in SLA that might be equal.
                                        {
                                                maybe=TRUE;
//                                                                      if(slAct->next==NULL && maybe==TRUE)
//                                                                      {
//                                                                      doNotAdd=FALSE;
//                                                                      slAct = slAct->next;
//                                                                      break;
//                                                                      }
//                                                                      else
//                                                                      slAct=slAct->next;
                                        }
                                                        //slAct = slAct->next;
                                                        //delete deleteMarker;                                                  
                                }//if(!isParallel(fNormal, slNormal))
                                if( (slAct->next==NULL) && (maybe==TRUE) )
                                {
                                        doNotAdd=FALSE;
                                        break;
                                }
                                slAct = slAct->next;
                                /* NOTE The following lines must not be here but rather called inside the if-block above.
                                Otherwise results get crappy. Unfortunately there are two slAct=slAct->next calls now,
                                (not nice!) but since they are in seperate branches of the if-statement there should not
                                be a way it gets called twice thus ommiting one facet:
                                slAct = slAct->next;*/                                          
                                                //delete deleteMarker;
                                                //deleteMarker=NULL;
                                                //if slAct was marked as to be deleted, delete it here!
                        }//while(slAct!=NULL)                                                                   
                        if( (notParallelCtr==lengthOfSearchList && removalOccured==FALSE) || (doNotAdd==FALSE) )
                                        //if( (notParallelCtr==lengthOfSearchList ) || doNotAdd==FALSE ) 
                        {
#ifdef gfan_DEBUG
                                cout << "Adding facet (";
                                fNormal->show(1,0);
                                cout << ") to SLA " << endl;
#endif
                                                //Add fAct to SLA
                                facet *marker;
                                marker = slEnd;
                                facet *f2Act;
                                f2Act = fAct->codim2Ptr;
                                                
                                slEnd->next = new facet();
                                slEnd = slEnd->next;
                                facet *slEndCodim2Root;
                                facet *slEndCodim2Act;
                                slEndCodim2Root = slEnd->codim2Ptr;
                                slEndCodim2Act = slEndCodim2Root;
                                                                
                                slEnd->setUCN(this->getUCN());
                                slEnd->isFlippable = TRUE;
                                slEnd->setFacetNormal(fNormal);
                                slEnd->prev = marker;
                                //Copy codim2-facets
                                intvec *f2Normal;// = new intvec(this->numVars);
                                while(f2Act!=NULL)
                                {
                                        f2Normal=f2Act->getFacetNormal();
                                        if(slEndCodim2Root==NULL)
                                        {
                                                slEndCodim2Root = new facet(2);
                                                slEnd->codim2Ptr = slEndCodim2Root;                     
                                                slEndCodim2Root->setFacetNormal(f2Normal);
                                                slEndCodim2Act = slEndCodim2Root;
                                        }
                                        else                                    
                                        {
                                                slEndCodim2Act->next = new facet(2);
                                                slEndCodim2Act = slEndCodim2Act->next;
                                                slEndCodim2Act->setFacetNormal(f2Normal);
                                        }
                                        f2Act = f2Act->next;
                                }
                                lengthOfSearchList++;                           
                        }//if( (notParallelCtr==lengthOfSearchList && removalOccured==FALSE) ||
                        fAct = fAct->next;
                }//if(fAct->isFlippable==TRUE)
                else
                {
                        fAct = fAct->next;
                }
        }//while(fAct!=NULL)                                            
        return slHead;
//                      delete sl2Normal;
//                      delete slNormal;
//                      delete f2Normal;
//                      delete fNormal;
}//addC2N
                
/** \brief Compute the gcd of two ints
 */
int gcone::intgcd(int a, int b)
{
        int r, p=a, q=b;
        if(p < 0)
                p = -p;
        if(q < 0)
                q = -q;
        while(q != 0)
        {
                r = p % q;
                p = q;
                q = r;
        }
        return p;
}               
                
/** \brief Construct a dd_MatrixPtr from a cone's list of facets
 * 
 */
dd_MatrixPtr gcone::facets2Matrix(gcone const &gc)
{
        facet *fAct;
        fAct = gc.facetPtr;
        
        dd_MatrixPtr M;
        dd_rowrange ddrows;
        dd_colrange ddcols;
        ddcols=(this->numVars)+1;
        ddrows=this->numFacets;
        dd_NumberType numb = dd_Integer;
        M=dd_CreateMatrix(ddrows,ddcols);                       
                        
        int jj=0;
        
        while(fAct!=NULL)
        {
                intvec *comp;
                comp = fAct->getFacetNormal();
                for(int ii=0;ii<this->numVars;ii++)
                {
                        dd_set_si(M->matrix[jj][ii+1],(*comp)[ii]);
                }
                jj++;
                fAct=fAct->next;                                
        }                       
                        
        return M;
}
                
/** \brief Write information about a cone into a file on disk
 *
 * This methods writes the information needed for the "second" method into a file.
 * The file's is divided in sections containing information on
 * 1) the ring
 * 2) the cone's Groebner Basis
 * 3) the cone's facets
 * Each line contains exactly one date
 * Each section starts with its name in CAPITALS
 */
void gcone::writeConeToFile(gcone const &gc, bool usingIntPoints)
{
        int UCN=gc.UCN;
        stringstream ss;
        ss << UCN;
        string UCNstr = ss.str();               
                        
        string prefix="/tmp/cone";
//      string prefix="./";     //crude hack -> run tests in separate directories
        string suffix=".sg";
        string filename;
        filename.append(prefix);
        filename.append(UCNstr);
        filename.append(suffix);
        
        
//      int thisPID = getpid();
//      ss << thisPID;
//      string strPID = ss.str();
//      string prefix="./";
                                                
        ofstream gcOutputFile(filename.c_str());
        facet *fAct;
        fAct = gc.facetPtr;                     
        facet *f2Act;
        f2Act=fAct->codim2Ptr;
        
        char *ringString = rString(currRing);
                        
        if (!gcOutputFile)
        {
                cout << "Error opening file for writing in writeConeToFile" << endl;
        }
        else
        {       
                gcOutputFile << "UCN" << endl;
                gcOutputFile << this->UCN << endl;
                gcOutputFile << "RING" << endl; 
                gcOutputFile << ringString << endl;
                gcOutputFile << "GCBASISLENGTH" << endl;
                gcOutputFile << IDELEMS(gc.gcBasis) << endl;                    
                //Write this->gcBasis into file
                gcOutputFile << "GCBASIS" << endl;                              
                for (int ii=0;ii<IDELEMS(gc.gcBasis);ii++)
                {                                       
                        gcOutputFile << p_String((poly)gc.gcBasis->m[ii],gc.baseRing) << endl;
                }                               
                                        
                gcOutputFile << "FACETS" << endl;                                                               
                
                while(fAct!=NULL)
                {       
                        intvec *iv;
                        intvec *iv2;
                        iv=fAct->getFacetNormal();
                        f2Act=fAct->codim2Ptr;
                        for (int ii=0;ii<iv->length();ii++)
                        {
                                if (ii<iv->length()-1)
                                {
                                        gcOutputFile << (*iv)[ii] << ",";
                                }
                                else
                                {
                                        gcOutputFile << (*iv)[ii] << " ";
                                }
                        }
                        while(f2Act!=NULL)
                        {
                                iv2=f2Act->getFacetNormal();    
                                for(int jj=0;jj<iv2->length();jj++)
                                {
                                        if (jj<iv2->length()-1)
                                        {
                                                gcOutputFile << (*iv2)[jj] << ",";
                                        }
                                        else
                                        {
                                                gcOutputFile << (*iv2)[jj] << " ";
                                        }
                                }
                                f2Act = f2Act->next;
                        }
                        gcOutputFile << endl;
                        fAct=fAct->next;
                }                       
        gcOutputFile.close();
        }
                        
}//writeConeToFile(gcone const &gc)
                
/** \brief Reads a cone from a file identified by its number
 */
void gcone::readConeFromFile(int UCN, gcone *gc)
{
        //int UCN=gc.UCN;
        stringstream ss;
        ss << UCN;
        string UCNstr = ss.str();
        string line;
        string strGcBasisLength;
        string strMonom, strCoeff, strCoeffNom, strCoeffDenom;          
        int gcBasisLength=0;
        int intCoeff=1;
        int intCoeffNom=1;              //better (number) but that's not compatible with stringstream;
        int intCoeffDenom=1;
        number nCoeff=nInit(1);
        number nCoeffNom=nInit(1);
        number nCoeffDenom=nInit(1);
        bool hasCoeffInQ = FALSE;       //does the polynomial have rational coeff?
        bool hasNegCoeff = FALSE;       //or a negative one?
        size_t found;                   //used for find_first_(not)_of

        string prefix="/tmp/cone";
        string suffix=".sg";
        string filename;
        filename.append(prefix);
        filename.append(UCNstr);
        filename.append(suffix);
                                        
        ifstream gcInputFile(filename.c_str(), ifstream::in);
        
        ring saveRing=currRing; 
        rChangeCurrRing(gc->baseRing);
        poly strPoly=pInit();
        poly resPoly=pInit();   //The poly to be read in
        
        string::iterator EOL;
        int terms=1;    //#Terms in the poly
        
        while( !gcInputFile.eof() )
        {
                getline(gcInputFile,line);
                hasCoeffInQ = FALSE;
                hasNegCoeff = FALSE;
                
                if(line=="GCBASISLENGTH")
                {
                        getline(gcInputFile, line);
                        strGcBasisLength = line;
                        gcBasisLength=atoi(strGcBasisLength.c_str());
                }
                if(line=="GCBASIS")
                {
                        for(int jj=0;jj<gcBasisLength;jj++)
                        {
                                getline(gcInputFile,line);
                                //find out how many terms the poly consists of
                                for(EOL=line.begin(); EOL!=line.end();++EOL)
                                {
                                        string s;
                                        s=*EOL;
                                        if(s=="+" || s=="-")
                                                terms++;
                                }
                                //magically convert strings into polynomials
                                //polys.cc:p_Read
                                //check until first occurance of + or -
                                //data or c_str
                                while(!line.empty())
                                {
                                        hasNegCoeff = FALSE;
                                        found = line.find_first_of("+-");       //get the first monomial
                                        string tmp;
                                        tmp=line[found];
//                                      if(found!=0 && (tmp.compare("-")==0) )
//                                              hasNegCoeff = TRUE;     //We have a coeff < 0
                                        if(found==0)
                                        {
                                                if(tmp.compare("-")==0)
                                                        hasNegCoeff = TRUE;
                                                line.erase(0,1);        //remove leading + or -
                                                found = line.find_first_of("+-");       //adjust found
                                        }
                                        strMonom = line.substr(0,found);
                                        line.erase(0,found);
                                        found = strMonom.find_first_of("/");
                                        if(found!=string::npos) //i.e. "/" exists in strMonom
                                        {
                                                hasCoeffInQ = TRUE;
                                                strCoeffNom=strMonom.substr(0,found);                                           
                                                strCoeffDenom=strMonom.substr(found+1,strMonom.find_first_not_of("1234567890"));
                                                strMonom.erase(0,found);
                                                strMonom.erase(0,strMonom.find_first_not_of("1234567890/"));                    
//                                              ss << strCoeffNom;
//                                              ss >> intCoeffNom;
//                                              nCoeffNom=(snumber*)strCoeffNom.c_str();
                                                nRead(strCoeffNom.c_str(), &nCoeffNom);
                                                nRead(strCoeffDenom.c_str(), &nCoeffDenom);
//                                              nCoeffNom=nInit(intCoeffNom);
//                                              ss << strCoeffDenom;
//                                              ss >> intCoeffDenom;
//                                              nCoeffDenom=nInit(intCoeffDenom);
//                                              nCoeffDenom=(snumber*)strCoeffNom.c_str();
                                                //NOTE NOT SURE WHETHER THIS WILL WORK!
                                                //nCoeffNom=nInit(intCoeffNom);
//                                              nCoeffDenom=(number)strCoeffDenom.c_str();
//                                              nCoeffDenom=(number)strCoeffDenom.c_str();
                                        }
                                        else
                                        {
                                                found = strMonom.find_first_not_of("1234567890");
                                                strCoeff = strMonom.substr(0,found);
                                                if(!strCoeff.empty())
                                                {
                                                        nRead(strCoeff.c_str(),&nCoeff);
                                                }
                                                else
                                                {
//                                                      intCoeff = 1;
                                                        nCoeff = nInit(1);
                                                }
                                                                                                
                                        }
                                        const char* monom = strMonom.c_str();
                                                
                                        p_Read(monom,strPoly,currRing);
                                        switch (hasCoeffInQ)
                                        {
                                                case TRUE:
                                                        if(hasNegCoeff)
                                                                nCoeffNom=nNeg(nCoeffNom);
//                                                              intCoeffNom *= -1;
//                                                      pSetCoeff(strPoly, nDiv((number)intCoeffNom, (number)intCoeffDenom));
                                                        pSetCoeff(strPoly, nDiv(nCoeffNom, nCoeffDenom));
                                                        break;
                                                case FALSE:
                                                        if(hasNegCoeff)
                                                                nCoeff=nNeg(nCoeff);
//                                                              intCoeff *= -1;
                                                        if(!nIsOne(nCoeff))
                                                        {
//                                                              if(hasNegCoeff)
//                                                                      intCoeff *= -1;
//                                                              pSetCoeff(strPoly,(number) intCoeff);
                                                                pSetCoeff(strPoly, nCoeff );
                                                        }
                                                        break;
                                                                                                        
                                        }
                                                //pSetCoeff(strPoly, (number) intCoeff);//Why is this set to zero instead of 1???
                                        if(pIsConstantComp(resPoly))
                                                resPoly=pCopy(strPoly);                                                 
                                        else
                                                resPoly=pAdd(resPoly,strPoly);
                                        
                                        
                                }//while(!line.empty())         
                        
                                gcBasis->m[jj]=pCopy(resPoly);
                                resPoly=NULL;   //reset
                        }
                        break;
                }               
        }//while(!gcInputFile.eof())
        
        gcInputFile.close();
        rChangeCurrRing(saveRing);
}
        
// static void gcone::idPrint(ideal &I)
// {
//      for(int ii=0;ii<IDELEMS(I);ii++)
//      {
//              cout << "_[" << ii << "]=" << I->m[ii] << endl;
//      }
// }
ring gcone::getBaseRing()
{
        return this->baseRing;
}
/** \brief Gather the output
* List of lists
*\param *gc Pointer to gcone, preferably gcRoot ;-)
*\param n the number of cones
*
*/
lists lprepareResult(gcone *gc, int n)
{
        gcone *gcAct;
        gcAct = gc;     
        facet *fAct;
        fAct = gc->facetPtr;
        
        lists res=(lists)omAllocBin(slists_bin);
        res->Init(n);   //initialize to store n cones
        for(int ii=0;ii<n;ii++)
        {
                res->m[ii].rtyp=LIST_CMD;
                lists l=(lists)omAllocBin(slists_bin);
                l->Init(6);
                l->m[0].rtyp=INT_CMD;
                l->m[0].data=(void*)gcAct->getUCN();
                l->m[1].rtyp=IDEAL_CMD;
                l->m[1].data=(void*)idrCopyR_NoSort(gcAct->gcBasis,gcAct->getBaseRing());
                
                l->m[2].rtyp=INTVEC_CMD;
                intvec iv=(gcAct->f2M(gcAct,gcAct->facetPtr));
                l->m[2].data=(void*)ivCopy(&iv);
                
                l->m[3].rtyp=LIST_CMD;
                        lists lCodim2List = (lists)omAllocBin(slists_bin);
                        lCodim2List->Init(gcAct->numFacets);            
 
                        fAct = gcAct->facetPtr;//fAct->codim2Ptr;
                        int jj=0;
                        while(fAct!=NULL && jj<gcAct->numFacets)
                        {
                                lCodim2List->m[jj].rtyp=INTVEC_CMD;
                                intvec ivC2=(gcAct->f2M(gcAct,fAct,2));
                                lCodim2List->m[jj].data=(void*)ivCopy(&ivC2);
                                jj++;
                                fAct = fAct->next;
                        }               
                l->m[3].data=(void*)lCodim2List;
                
                
                l->m[4].rtyp=RING_CMD;
                l->m[4].data=(void*)(gcAct->getBaseRing());             
                l->m[5].rtyp=INT_CMD;
                l->m[5].data=(void*)gcAct->getPredUCN();
                res->m[ii].data=(void*)l;
                gcAct = gcAct->next;
        }               
        
        return res;
}
/** \brief Write facets of a cone into a matrix
* Takes a pointer to a facet as 2nd arg 
* f should always point to gc->facetPtr
* param n is used to determine whether it operates in codim 1 or 2
*
*/
intvec gcone::f2M(gcone *gc, facet *f, int n)
{
        facet *fAct;
        intvec *res;
        intvec *fNormal = new intvec(gc->numVars);
//      int codim=n;
//      int bound;
//      if(f==gc->facetPtr)
        if(n==1)
        {
                intvec *m1Res=new intvec(gc->numFacets,gc->numVars,0);
                res = m1Res;
                fAct = gc->facetPtr;
//              bound = gc->numFacets*(this->numVars);          
        }
        else
        {
                fAct = f->codim2Ptr;
                intvec *m2Res = new intvec(f->numCodim2Facets,gc->numVars,0);
                res = m2Res;            
//              bound = fAct->numCodim2Facets*(this->numVars);

        }
        int ii=0;
        while(fAct!=NULL )//&& ii < bound )
        {
                fNormal = fAct->getFacetNormal();
                for(int jj=0;jj<this->numVars;jj++)
                {
                        (*res)[ii]=(*fNormal)[jj];
                        ii++;
                }
                fAct = fAct->next;
        }

        delete fNormal;
        return *res;
}

int gcone::counter=0;
int gfanHeuristic;
// ideal gfan(ideal inputIdeal, int h)
lists gfan(ideal inputIdeal, int h)
{
        lists lResList; //this is the object we return
        
        if(rHasGlobalOrdering(currRing))
        {       
        int numvar = pVariables; 
        gfanHeuristic = h;
        
        enum searchMethod {
                reverseSearch,
                noRevS
        };
        
        searchMethod method;
        method = noRevS;

        
#ifdef gfan_DEBUG
        cout << "Now in subroutine gfan" << endl;
#endif
        ring inputRing=currRing;        // The ring the user entered
        ring rootRing;                  // The ring associated to the target ordering
        ideal res;      
        facet *fRoot;   
        
        if(method==noRevS)
        {
                gcone *gcRoot = new gcone(currRing,inputIdeal);
                gcone *gcAct;
                gcAct = gcRoot;
                gcAct->numVars=pVariables;
                gcAct->getGB(inputIdeal);               
#ifndef NDEBUG
                cout << "GB of input ideal is:" << endl;
                idShow(gcAct->gcBasis);
#endif
                if(gcAct->isMonomial(gcAct->gcBasis))
                {
                        WerrorS("Monomial input - terminating");
                        res=gcAct->gcBasis;
                        //break;
                }
                cout << endl;
                gcAct->getConeNormals(gcAct->gcBasis);          
                gcAct->noRevS(*gcAct);          
                //res=gcAct->gcBasis;
                //Below is a workaround, since gcAct->gcBasis gets deleted in noRevS
                res = inputIdeal; 
                lResList=lprepareResult(gcRoot,gcRoot->getCounter());
//              res=lResList;
        }
        dd_free_global_constants();
        }//rHasGlobalOrdering
        else
        {
                WerrorS("Ring has non-global ordering - terminating");
                lResList->Init(1);
                lResList->m[0].rtyp=INT_CMD;
                int ires=0;
                lResList->m[0].data=(void*)&ires;
        }
        
        return lResList;
}

#endif