Changeset 297e92 in git

Timestamp:

Sep 27, 2011, 3:53:23 PM (12 years ago)

Author:

Martin Lee <martinlee84@…>

Branches:

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

Children:

30a68478d0ec6f1ae5fc55c6907b025bedae4404

Parents:

563364d1cd5bd1d1a7baf4123776a2bd37d99f23

Message:

added equality test before testing divisibility and multiply by gcd of contents
in chinrem_gcd


git-svn-id: file:///usr/local/Singular/svn/trunk@14386 2c84dea3-7e68-4137-9b89-c4e89433aadc

File:

• factory/cf_gcd.cc (modified) (6 diffs)

factory/cf_gcd.cc

@@ -1156 +1156 @@
 CanonicalForm chinrem_gcd ( const CanonicalForm & FF, const CanonicalForm & GG )
 {
-  bool saveRat= isOn (SW_RATIONAL);
-  if (!saveRat)
-    On (SW_RATIONAL);
-  CanonicalForm f, g, cg, cl, q(0), Dp, newD, D, newq;
+  CanonicalForm f, g, cl, q(0), Dp, newD, D, newq;
   int p, i, dp_deg, d_deg=-1;
 
   CanonicalForm cd ( bCommonDen( FF ));
   f=cd*FF;
-  f /=vcontent(f,Variable(1));
+  Variable x= Variable (1);
+  CanonicalForm cf, cg;
+  cf= icontent (f);
+  f /= cf;
   //cd = bCommonDen( f ); f *=cd;
   //f /=vcontent(f,Variable(1));
@@ -1170 +1170 @@
   cd = bCommonDen( GG );
   g=cd*GG;
-  g /=vcontent(g,Variable(1));
+  cg= icontent (g);
+  g /= cg;
   //cd = bCommonDen( g ); g *=cd;
   //g /=vcontent(g,Variable(1));
 
+  CanonicalForm Dn, test= 0;
+  bool equal= false;
   i = cf_getNumBigPrimes() - 1;
-  cl =  f.lc()* g.lc();
-
-  Off (SW_RATIONAL);
+  cl =  gcd (f.lc(),g.lc());
+
+  CanonicalForm gcdcfcg= gcd (cf, cg);
+  //Off (SW_RATIONAL);
   while ( true )
   {
@@ -1196 +1200 @@
     {
       //printf(" -> 1\n");
-      if (saveRat)
-        On (SW_RATIONAL);
-      return CanonicalForm(1);
+      return CanonicalForm(gcdcfcg);
     }
     if ( q.isZero() )
@@ -1221 +1223 @@
         D = mapinto( Dp );
         d_deg=dp_deg;
+        test= 0;
+        equal= false;
       }
       else
@@ -1230 +1234 @@
     if ( i >= 0 )
     {
+      Dn= Farey(D,q);
+      int is_rat= isOn (SW_RATIONAL);
       On (SW_RATIONAL);
-      CanonicalForm Dn= Farey(D,q);
-      CanonicalForm cd = bCommonDen( Dn ); // we need On(SW_RATIONAL)
+      cd = bCommonDen( Dn ); // we need On(SW_RATIONAL)
+      if (!is_rat)
+        Off (SW_RATIONAL);
       Dn *=cd;
+      if (test != Dn)
+        test= Dn;
+      else
+        equal= true;
       //Dn /=vcontent(Dn,Variable(1));
-      if ( fdivides( Dn, f ) && fdivides( Dn, g ) )
+      if (equal && fdivides( Dn, f ) && fdivides( Dn, g ) )
       {
-        if (!saveRat)
-          Off (SW_RATIONAL);
         //printf(" -> success\n");
-        return Dn;
+        return Dn*gcdcfcg;
       }
-      Off (SW_RATIONAL);
+      equal= false;
       //else: try more primes
     }
@@ -1248 +1257 @@
     { // try other method
       //printf("try other gcd\n");
-      if (saveRat)
-        On (SW_RATIONAL);
       Off(SW_USE_CHINREM_GCD);
       D=gcd_poly( f, g );
       On(SW_USE_CHINREM_GCD);
-      return D;
+      return D*gcdcfcg;
     }
   }