Changeset 2488dc3 in git for factory/cf_gcd.cc

Timestamp:

May 11, 2012, 5:46:42 PM (11 years ago)

Author:

Martin Lee <martinlee84@…>

Branches:

(u'jengelh-datetime', 'ceac47cbc86fe4a15902392bdbb9bd2ae0ea02c6')(u'spielwiese', 'f875bbaccd0831e36aaed09ff6adeb3eb45aeb94')

Children:

ea5ff1d5094b84bbc2e29abd61b17ca3343f5c23

Parents:

72bfc80277ea4841efcc1006285e513061f17917

git-author:

Martin Lee <martinlee84@web.de>2012-05-11 17:46:42+02:00

git-committer:

Martin Lee <martinlee84@web.de>2012-07-31 11:31:14+02:00

Message:

chg: use other GCD if input is not dense in chinrem_gcd

File:

• factory/cf_gcd.cc (modified) (3 diffs)

factory/cf_gcd.cc

@@ -1233 +1233 @@
   cl =  gcd (f.lc(),g.lc());
   CanonicalForm gcdcfcg= gcd (cf, cg);
+  CanonicalForm fp, gp;
   CanonicalForm b= 1;
   int minCommonDeg= 0;
@@ -1260 +1261 @@
 
   CanonicalForm cof, cog, cofp, cogp, newCof, newCog, cofn, cogn;
+  int maxNumVars= tmax (getNumVars (f), getNumVars (g));
   //Off (SW_RATIONAL);
   while ( true )
@@ -1272 +1274 @@
     //printf("try p=%d\n",p);
     setCharacteristic( p );
+    fp= mapinto (f);
+    gp= mapinto (g);
 #ifdef HAVE_NTL
-    Dp = GCD_small_p (mapinto (f), mapinto (g), cofp, cogp);
+    if (size (fp)/maxNumVars > 500 && size (gp)/maxNumVars > 500)
+      Dp = GCD_small_p (fp, gp, cofp, cogp);
+    else
+    {
+      Dp= gcd_poly (fp, gp);
+      cofp= fp/Dp;
+      cogp= gp/Dp;
+    }
 #else
-    Dp= gcd_poly (mapinto (f), mapinto (g));
-    cofp= mapinto (f)/Dp;
-    cogp= mapinto (g)/Dp;
+    Dp= gcd_poly (fp, gp);
+    cofp= fp/Dp;
+    cogp= gp/Dp;
 #endif
     Dp /=Dp.lc();