Changeset 56d3c6 in git for factory/cf_gcd.cc

Timestamp:

Aug 18, 2011, 3:49:51 PM (13 years ago)

Author:

Martin Lee <martinlee84@…>

Branches:

(u'spielwiese', '17f1d200f27c5bd38f5dfc6e8a0879242279d1d8')

Children:

12483db42b3ad1ac5499765c4350a6a67250d9c7

Parents:

e39eb55793d9d07bba08d482817c1e843a5523df

Message:

prefer chinrem_gcd to ezgcd 
removed some unused code
switched off gcd_avoid_mtaildegree
handle SW_RATIONAL in chinrem_gcd


git-svn-id: file:///usr/local/Singular/svn/trunk@14373 2c84dea3-7e68-4137-9b89-c4e89433aadc

File:

• factory/cf_gcd.cc (modified) (11 diffs)

factory/cf_gcd.cc

@@ -683 +683 @@
   bool gc_isUnivariate=g.isUnivariate();
   bool fc_and_gc_Univariate=fc_isUnivariate && gc_isUnivariate;
-#if 1
-  if (( getCharacteristic() == 0 )
-  && (f.level() >4)
-  && (g.level() >4)
-  && isOn( SW_USE_CHINREM_GCD)
-  && (!fc_and_gc_Univariate)
-  && (isPurePoly_m(f))
-  && (isPurePoly_m(g))
-  )
-  {
-      return chinrem_gcd( f, g );
-  }
-#endif
   cf_prepgcd( f, g, cc, p1, pe);
   if ( cc != 0 )
@@ -714 +701 @@
   fc = f;
   gc = g;
-  if( gcd_avoid_mtaildegree ( fc, gc, d1 ) )
-      return d1;
   if ( getCharacteristic() != 0 )
   {
@@ -727 +712 @@
     else if ((!fc_and_gc_Univariate) && (isOn( SW_USE_EZGCD_P )))
     {
-      /*if ( pe == 1 )
-        fc = fin_ezgcd( fc, gc );
-      else if ( pe > 0 )// no variable at position 1
-      {
-        fc = replacevar( fc, Variable(pe), Variable(1) );
-        gc = replacevar( gc, Variable(pe), Variable(1) );
-        fc = replacevar( fin_ezgcd( fc, gc ), Variable(1), Variable(pe) );
-      }
-      else
-      {
-        pe = -pe;
-        fc = swapvar( fc, Variable(pe), Variable(1) );
-        gc = swapvar( gc, Variable(pe), Variable(1) );
-        fc = swapvar( fin_ezgcd( fc, gc ), Variable(1), Variable(pe) );
-      }*/
       fc= EZGCD_P (fc, gc);
     }
@@ -774 +744 @@
     if (
     isOn(SW_USE_CHINREM_GCD)
-    && (gc.level() >5)
-    && (fc.level() >5)
     && (isPurePoly_m(fc)) && (isPurePoly_m(gc))
     )
@@ -810 +778 @@
       }
     }
-    else if (
-    isOn(SW_USE_CHINREM_GCD)
-    && (isPurePoly_m(fc)) && (isPurePoly_m(gc))
-    )
-    {
-    #if 0
-      if ( p1 == fc.level() )
-        fc = chinrem_gcd( fc, gc );
-      else
-      {
-        fc = replacevar( fc, Variable(p1), Variable(mp) );
-        gc = replacevar( gc, Variable(p1), Variable(mp) );
-        fc = replacevar( chinrem_gcd( fc, gc ), Variable(mp), Variable(p1) );
-      }
-    #else
-      fc = chinrem_gcd( fc, gc);
-    #endif
-    }
     else
     {
@@ -1021 +971 @@
             else
             {
+                //printf ("here\n");
                 CanonicalForm cdF = bCommonDen( f );
                 CanonicalForm cdG = bCommonDen( g );
@@ -1288 +1239 @@
 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;
   int p, i, dp_deg, d_deg=-1;
@@ -1306 +1260 @@
   cl =  f.lc()* g.lc();
 
+  Off (SW_RATIONAL);
   while ( true )
   {
@@ -1324 +1279 @@
     {
       //printf(" -> 1\n");
+      if (saveRat)
+        On (SW_RATIONAL);
       return CanonicalForm(1);
     }
@@ -1356 +1313 @@
     if ( i >= 0 )
     {
+      On (SW_RATIONAL);
       CanonicalForm Dn= Farey(D,q);
-      int is_rat=isOn(SW_RATIONAL);
-      On(SW_RATIONAL);
       CanonicalForm cd = bCommonDen( Dn ); // we need On(SW_RATIONAL)
-      if (!is_rat) Off(SW_RATIONAL);
       Dn *=cd;
       //Dn /=vcontent(Dn,Variable(1));
       if ( fdivides( Dn, f ) && fdivides( Dn, g ) )
       {
+        if (!saveRat)
+          Off (SW_RATIONAL);
         //printf(" -> success\n");
         return Dn;
       }
+      Off (SW_RATIONAL);
       //else: try more primes
     }
@@ -1373 +1331 @@
     { // try other method
       //printf("try other gcd\n");
+      if (saveRat)
+        On (SW_RATIONAL);
       Off(SW_USE_CHINREM_GCD);
       D=gcd_poly( f, g );