Changeset 2b7bb5d in git for kernel/gfan.cc

Timestamp:

Apr 1, 2009, 4:07:20 PM (14 years ago)

Author:

Martin Monerjan

Branches:

(u'jengelh-datetime', 'ceac47cbc86fe4a15902392bdbb9bd2ae0ea02c6')(u'spielwiese', '0604212ebb110535022efecad887940825b97c3f')

Children:

7bd7795642f49e279d1fb82377b04df64f84a771

Parents:

798f72186f85eaf9224aef1590336c69ccc6a3f9

Message:

Continued work on gcone::flip - HIGHLY EXPERIMENTAL CODE!
Added public variable gcone::numVars to store #of variables
Began work on bool gcone::isParallel


git-svn-id: file:///usr/local/Singular/svn/trunk@11609 2c84dea3-7e68-4137-9b89-c4e89433aadc

File:

• kernel/gfan.cc (modified) (7 diffs)

kernel/gfan.cc

@@ -2 +2 @@
 Compute the Groebner fan of an ideal
 $Author: monerjan $
-$Date: 2009-03-31 09:59:14 $
-$Header: /exports/cvsroot-2/cvsroot/kernel/gfan.cc,v 1.25 2009-03-31 09:59:14 monerjan Exp $
-$Id: gfan.cc,v 1.25 2009-03-31 09:59:14 monerjan Exp $
+$Date: 2009-04-01 14:07:20 $
+$Header: /exports/cvsroot-2/cvsroot/kernel/gfan.cc,v 1.26 2009-04-01 14:07:20 monerjan Exp $
+$Id: gfan.cc,v 1.26 2009-04-01 14:07:20 monerjan Exp $
 */
 
@@ -103 +103 @@
 {
         private:
-                int numFacets;          //#of facets of the cone
+                int numFacets;          //#of facets of the cone                
 
         public:
@@ -116 +116 @@
                 }
                 ~gcone();               //destructor
+                
                 /** Pointer to the first facet */
-                facet *facetPtr;        //Will hold the adress of the first facet
+                facet *facetPtr;        //Will hold the adress of the first facet; set by gcone::getConeNormals
                 poly gcMarkedTerm;      //marked terms of the cone's Groebner basis
-                ideal gcBasis;          //GB of the cone
+                int numVars;            //#of variables in the ring
+                
+                /** Contains the Groebner basis of the cone. Is set by gcone::getGB(ideal I)*/
+                ideal gcBasis;          //GB of the cone, set by gcone::getGB();
                 gcone *next;            //Pointer to *previous* cone in search tree
+                
                 /** \brief Compute the normals of the cone
                 *
@@ -127 +132 @@
                 * 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
+                * 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.
                 */
@@ -287 +293 @@
                 }//method getConeNormals(ideal I)       
                 
+                bool isParallel(int v[], intvec iv)
+                {
+                }
+                
                 /** \brief Compute the Groebner Basis on the other side of a shared facet 
                 *
@@ -293 +303 @@
                 * 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$
-                * Checking for parallelity is done by computing the rank of the matrix consisting of the vectors in question.
-                * Another possibility would be to compute an interior point of the facet and taking all terms having the same
-                * weight with respect to this interior point.
+                * Checking for parallelity is done by brute force dividing of components.
+                * Other possibilitiesincludes  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 flip(ideal I, facet *f)            //Compute "the other side"
-                {
+                void flip(ideal gb, facet *f)           //Compute "the other side"
+                {                       
+                        intvec fNormal; //facet normal, check for parallelity
+                        /* EXTREMELY EXPERIMENTAL CODE AHEAD*/
                         /*1st step: Compute the initial ideal*/
-                        map mapping;
-                        idhdl h;
-                        ideal image;
-                        mapping=IDMAP(h);
-                        image=idInit(1,1);
-                        image=maGetPreimage(currRing,mapping,image);                    
-                }
+                        poly initialForm[IDELEMS(gb)];  //array of #polys in GB to store initial form
+                        poly aktpoly;
+                        int check[this->numVars];       //array to store the difference of LE and v
+                        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)
+                                initialForm[ii]=pHead(aktpoly);
+                                while(pNext(aktpoly)!=NULL)     /*loop trough terms and check for parallelity*/
+                                {
+                                        aktpoly=pNext(aktpoly); //next term
+                                        pGetExpV(aktpoly,v);
+                                        for (int i=0;i<pVariables;i++)
+                                        {
+                                                check[i] = v[i]-leadExpV[i];
+                                        }
+                                        if (isParallel(*check,fNormal)) //pass *check when 
+                                        {
+                                                //initialForm[ii] += pHead(aktpoly);    //This should add the respective term to 
+                                        }                               
+                                }
+                                
+                        }
+                }//void flip(ideal gb, facet *f)
                                 
                 /** \brief Compute a Groebner Basis
                 *
-                * Computes the Groebner basis and stores the result in this->gcBasis
+                * Computes the Groebner basis and stores the result in gcone::gcBasis
                 *\param ideal
                 *\return void
@@ -381 +414 @@
         gcone *gcAct;
         gcAct = gcRoot;
+        gcAct->numVars=pVariables;
         gcAct->getGB(inputIdeal);
         gcAct->getConeNormals(gcAct->gcBasis);  //hopefully compute the normals