Changeset a38d45 in git for libfac

Timestamp:

Oct 25, 2007, 4:45:41 PM (16 years ago)

Author:

Hans Schönemann <hannes@…>

Branches:

(u'spielwiese', 'fe61d9c35bf7c61f2b6cbf1b56e25e2f08d536cc')

Children:

e520c56ea1ed45204b85b9d87163d60d99556985

Parents:

4a4d6fc2217aa5457f704ed86513b02ed28c11f2

Message:

*hannes: homgfactor for alg.ext of Q


git-svn-id: file:///usr/local/Singular/svn/trunk@10344 2c84dea3-7e68-4137-9b89-c4e89433aadc

Location:

libfac/factor

Files:

• Factor.cc (modified) (8 diffs)
• homogfactor.cc (modified) (5 diffs)

libfac/factor/Factor.cc

@@ -1 +1 @@
 /* Copyright 1996 Michael Messollen. All rights reserved. */
 ///////////////////////////////////////////////////////////////////////////////
-static char * rcsid = "$Id: Factor.cc,v 1.36 2007-10-15 18:03:11 Singular Exp $ ";
+static char * rcsid = "$Id: Factor.cc,v 1.37 2007-10-25 14:45:41 Singular Exp $ ";
 static char * errmsg = "\nYou found a bug!\nPlease inform (Michael Messollen) michael@math.uni-sb.de \nPlease include above information and your input (the ideal/polynomial and characteristic) in your bug-report.\nThank you.";
 ///////////////////////////////////////////////////////////////////////////////
@@ -29 +29 @@
 
 #include "alg_factor.h"
+void out_cf(char *s1,const CanonicalForm &f,char *s2);
+void out_cff(CFFList &L);
+
 
 #ifdef SINGULAR
@@ -53 +56 @@
 TIMING_DEFINE_PRINT(hensel_time);
 TIMING_DEFINE_PRINT(truefactor_time);
-
-void out_cf(char *s1,const CanonicalForm &f,char *s2);
 
 /*
@@ -1123 +1124 @@
 Factorize(const CanonicalForm & F, const CanonicalForm & minpoly, int is_SqrFree )
 {
+  //out_cf("Factorize: F=",F,"\n");
+  //out_cf("           minpoly:",minpoly,"\n");
   CFFList Outputlist,SqrFreeList,Intermediatelist,Outputlist2;
   ListIterator<CFFactor> i,j;
@@ -1147 +1150 @@
     if (minpoly!=0)
     {
-      CFList as(minpoly);
-      CFFList sqF=sqrFree(F); // sqrFreeZ
-      CFFList G,H;
-      CanonicalForm fac;
-      int d;
-      ListIterator<CFFactor> i,k;
-      for ( i = sqF; i.hasItem(); ++i )
+      if ( F.isHomogeneous() )
       {
-        d = i.getItem().exp();
-        fac = i.getItem().factor();
-        G = newfactoras( fac, as, 1);
-        for ( k = G; k.hasItem(); ++k )
+        DEBOUTLN(CERR, "Poly is homogeneous! : ", F);
+        // Now we can substitute one variable to 1, factorize and then
+        // look on the resulting factors and their monomials for
+        // backsubstitution of the substituted variable.
+        Outputlist=HomogFactor(F, minpoly, 0);
+      }
+      else
+      {
+        CFList as(minpoly);
+        CFFList sqF=sqrFree(F); // sqrFreeZ
+        CFFList G,H;
+        CanonicalForm fac;
+        int d;
+        ListIterator<CFFactor> i,k;
+        for ( i = sqF; i.hasItem(); ++i )
         {
-          fac = k.getItem().factor();
-          int dd = k.getItem().exp();
-          H.append( CFFactor( fac , d*dd ) );
+          d = i.getItem().exp();
+          fac = i.getItem().factor();
+          G = newfactoras( fac, as, 1);
+          for ( k = G; k.hasItem(); ++k )
+          {
+            fac = k.getItem().factor();
+            int dd = k.getItem().exp();
+            H.append( CFFactor( fac , d*dd ) );
+          }
         }
-      }
-      //Outputlist = newfactoras( F, as, 1);
-      Outputlist = H;
+        //Outputlist = newfactoras( F, as, 1);
+        Outputlist = H;
+      }
     }
     else
@@ -1178 +1192 @@
     DEBDECLEVEL(CERR, "Factorize");
     TIMING_PRINT(factorize_time, "\ntime used for factorization   : ");
+    //out_cff(Outputlist);
     return Outputlist;
   }
@@ -1297 +1312 @@
   if(isOn(SW_USE_NTL_SORT)) Outputlist2.sort(cmpCF);
 
+  //out_cff(Outputlist2);
   return Outputlist2;
 }
@@ -1302 +1318 @@
 /*
 $Log: not supported by cvs2svn $
+Revision 1.36  2007/10/15 18:03:11  Singular
+*hannes: // debug stuff
+
 Revision 1.35  2007/06/14 14:16:35  Singular
 *hannes: Factorize2 etc.

libfac/factor/homogfactor.cc

@@ -1 +1 @@
 /* Copyright 1997 Michael Messollen. All rights reserved. */
 ////////////////////////////////////////////////////////////
-// static char * rcsid = "$Id: homogfactor.cc,v 1.7 2006-05-16 14:46:50 Singular Exp $ ";
+// static char * rcsid = "$Id: homogfactor.cc,v 1.8 2007-10-25 14:45:41 Singular Exp $ ";
 ////////////////////////////////////////////////////////////
 // FACTORY - Includes
@@ -25 +25 @@
 #include "homogfactor.h"
 
+void out_cf(char *s1,const CanonicalForm &f,char *s2);
+
+CFFList Factorize2(CanonicalForm F, const CanonicalForm & minpoly );
+
 #ifdef HFACTORDEBUG
 #  define DEBUGOUTPUT
@@ -134 +138 @@
 // we assume g is square-free
 CFFList
-HomogFactor( const CanonicalForm & g, const CanonicalForm  & minpoly, const int Mainvar ){
+HomogFactor( const CanonicalForm & g, const CanonicalForm  & minpoly, const int Mainvar )
+{
   DEBINCLEVEL(CERR, "HomogFactor");
   Variable xn = get_max_degree_Variable(g);
   int d_xn = degree(g,xn);
-  CFMap n;
-  CanonicalForm F = compress(g(1,xn),n); // must compress F! 
+  CanonicalForm F = g(1,xn);
 
   DEBOUTLN(CERR, "xn= ", xn);
@@ -148 +152 @@
   // 
   CFFList Intermediatelist;
-  if ( getCharacteristic() > 0 )
-     Intermediatelist = Factorized(F, minpoly, Mainvar);
-  else
-     Intermediatelist = factorize(F); // what support for char==0 ?
   CFFList Homoglist;
   CFFListIterator j;
-  for ( j=Intermediatelist; j.hasItem(); j++ )
-    Homoglist.append(CFFactor( n(j.getItem().factor()), j.getItem().exp()) );
+  if ( getCharacteristic() > 0 )
+  {
+     CFMap n;
+     Intermediatelist = Factorized(compress(F,n), minpoly, Mainvar);
+     for ( j=Intermediatelist; j.hasItem(); j++ )
+       Homoglist.append(CFFactor( n(j.getItem().factor()), j.getItem().exp()) );
+  }
+  else
+     Homoglist = Factorize2(F, minpoly);
   // Now we have uncompressed factors in Homoglist
   DEBOUTLN(CERR, "F factors as: ", Homoglist);
   CFFList Unhomoglist;
   CanonicalForm unhomogelem;
-  for ( j=Homoglist; j.hasItem(); j++ ){
-    DEBOUTLN(CERR, "Homogenizing ",j.getItem().factor()); 
-    unhomogelem= homogenize(j.getItem().factor(),xn);
-    DEBOUTLN(CERR, "      that is ", unhomogelem);
-    Unhomoglist.append(CFFactor(unhomogelem,j.getItem().exp()));
-    d_xn -= degree(unhomogelem,xn)*j.getItem().exp();
+  if ((!minpoly.isZero()) &&(getCharacteristic() == 0) )
+  {
+    for ( j=Homoglist; j.hasItem(); j++ )
+    {
+      // assume that minpoly.level() < level of all "real" variables of g
+      DEBOUTLN(CERR, "Homogenizing ",j.getItem().factor()); 
+      unhomogelem= homogenize(j.getItem().factor(),xn,
+                         Variable(minpoly.level()+1),g.mvar());
+      DEBOUTLN(CERR, "      that is ", unhomogelem);
+      Unhomoglist.append(CFFactor(unhomogelem,j.getItem().exp()));
+      d_xn -= degree(unhomogelem,xn)*j.getItem().exp();
+    }
+  }
+  else
+  {
+    for ( j=Homoglist; j.hasItem(); j++ )
+    {
+      DEBOUTLN(CERR, "Homogenizing ",j.getItem().factor()); 
+      unhomogelem= homogenize(j.getItem().factor(),xn);
+      DEBOUTLN(CERR, "      that is ", unhomogelem);
+      Unhomoglist.append(CFFactor(unhomogelem,j.getItem().exp()));
+      d_xn -= degree(unhomogelem,xn)*j.getItem().exp();
+    }
   }
   DEBOUTLN(CERR, "Power of xn to append is ", d_xn);
@@ -177 +201 @@
 /*
 $Log: not supported by cvs2svn $
+Revision 1.7  2006/05/16 14:46:50  Singular
+*hannes: gcc 4.1 fixes
+
 Revision 1.6  2005/12/09 08:36:11  Singular
 *hannes: stuff for homog. polys ->factory