Changeset 08a6ebb in git

Timestamp:

Sep 26, 2007, 4:31:12 PM (16 years ago)

Author:

Hans Schönemann <hannes@…>

Branches:

(u'spielwiese', '8e0ad00ce244dfd0756200662572aef8402f13d5')

Children:

f4b18020f64669b26ca1cbe58482a4d2d8178a49

Parents:

8b388e1e07f2e848edfe629e622f372c9b16c0ea

Message:

*hannes: farey fixed


git-svn-id: file:///usr/local/Singular/svn/trunk@10312 2c84dea3-7e68-4137-9b89-c4e89433aadc

Location:

factory

Files:

• cf_chinese.cc (modified) (4 diffs)
• cf_gcd.cc (modified) (6 diffs)

factory/cf_chinese.cc

@@ -1 +1 @@
 /* emacs edit mode for this file is -*- C++ -*- */
-/* $Id: cf_chinese.cc,v 1.11 2007-09-26 09:17:39 Singular Exp $ */
+/* $Id: cf_chinese.cc,v 1.12 2007-09-26 14:31:12 Singular Exp $ */
 
 //{{{ docu
@@ -162 +162 @@
 {
    //assume(P>0);
-   if (N<0){N=N+P;}
+   // assume !isOn(SW_RATIONAL): mod is a no-op otherwise 
+   if (N<0) N +=P;
    CanonicalForm A,B,C,D,E;
    E=P;
    B=1;
-   while (N!=0)
+   while (!N.isZero())
    {
         if (2*N*N<P)
         {
-           return(N/B);
-        }
-        D=E % N;
-        C=A-(E-E % N)/N*B;
+           On(SW_RATIONAL);
+           N /=B;
+           Off(SW_RATIONAL);
+           return(N);
+        }
+        D=mod(E , N);
+        C=A-(E-mod(E , N))/N*B;
         E=N;
         N=D;
@@ -184 +188 @@
 CanonicalForm Farey ( const CanonicalForm & f, const CanonicalForm & q )
 {
+    int is_rat=isOn(SW_RATIONAL);
+    Off(SW_RATIONAL);
     Variable x = f.mvar();
     CanonicalForm result = 0;
@@ -198 +204 @@
           result += power( x, i.exp() ) * Farey(c,q);
     }
+    if (is_rat) On(SW_RATIONAL);
     return result;
 }

factory/cf_gcd.cc

@@ -1 +1 @@
 /* emacs edit mode for this file is -*- C++ -*- */
-/* $Id: cf_gcd.cc,v 1.50 2007-09-26 09:17:39 Singular Exp $ */
+/* $Id: cf_gcd.cc,v 1.51 2007-09-26 14:31:12 Singular Exp $ */
 
 #include <config.h>
@@ -983 +983 @@
 
 #define GCD_CHINES_MIN_TRIES 3
-#define GCD_CHINES_MAX_TRIES 7
 CanonicalForm chinrem_gcd ( const CanonicalForm & FF, const CanonicalForm & GG )
 {
@@ -992 +991 @@
   f=cd*FF;
   f /=vcontent(f,Variable(1));
-  cd = bCommonDen( f ); f *=cd;
-  f /=vcontent(f,Variable(1));
+  //cd = bCommonDen( f ); f *=cd;
+  //f /=vcontent(f,Variable(1));
 
   cd = bCommonDen( GG );
   g=cd*GG;
   g /=vcontent(g,Variable(1));
-  cd = bCommonDen( g ); g *=cd;
-  g /=vcontent(g,Variable(1));
+  //cd = bCommonDen( g ); g *=cd;
+  //g /=vcontent(g,Variable(1));
 
   q = 0;
@@ -1018 +1017 @@
     n--;
     Dp = gcd( mapinto( f ), mapinto( g ) );
+    Dp /=Dp.lc();
     setCharacteristic( 0 );
     dp_deg=totaldegree(Dp);
@@ -1036 +1036 @@
         D = newD;
       }
-      else if ( dp_deg < d_deg )
+      else if ( dp_deg > d_deg )
       {
         n=GCD_CHINES_MIN_TRIES;
@@ -1044 +1044 @@
         d_deg=dp_deg;
       }
-      //else
-      //  printf("bad prime\n");
-      // else p is a bad prime
-    }
-    if (( i >= 0 ) && (n >= GCD_CHINES_MIN_TRIES-GCD_CHINES_MAX_TRIES))
+      //else dp_deg < d_deg: bad prime
+    }
+    if ( i >= 0 )
     {
       if (n<=0)
       {
-      // now balance D mod q
-      //CanonicalForm Dn = balance_p( D, q );
-      //out_cf("test ",Dn,"\n");
-      //if ( fdivides( Dn, f ) && fdivides( Dn, g ) )
-      //{
-      //  //printf("does divide\n");
-      //  return Dn;
-      //}
-      CanonicalForm Dn= Farey(D,q);
-      CanonicalForm cd = bCommonDen( Dn );
-      Dn *=cd;
-      Dn /=vcontent(Dn,Variable(1));
-      if ( fdivides( Dn, f ) && fdivides( Dn, g ) )
-      {
-        //printf("does divide\n");
-        return Dn;
+        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 ) )
+        {
+          return Dn;
+        }
+      //else: try more primes
       }
-      //else
-      // printf("does not divide\n");
-      }
-    }
-    else
-    {
-      #if 0
-      printf("primes left:%d, tries left:%d, gcd-deg:%d\n",i,n,d_deg);
-      out_cf("f= ",f,"\n");
-      out_cf("g= ",g,"\n");
-      CanonicalForm Dn= Farey(D,q);
-      CanonicalForm cd = bCommonDen( Dn );
-      Dn *=cd;
-      Dn /=vcontent(Dn,Variable(1));
-      out_cf("farey: ",Dn,"\n"); 
-      #endif
+    }
+    else
+    {
       Off(SW_USE_CHINREM_GCD);
       D=gcd_poly( f, g );
       On(SW_USE_CHINREM_GCD);
-      #if 0
-      out_cf("gcd: ",D,"\n"); 
-      #endif
       return D;
     }