===================================================================
RCS file: /home/cvs/OpenXM/src/kan96xx/Kan/gb.c,v
retrieving revision 1.7
retrieving revision 1.9
diff -u -p -r1.7 -r1.9
--- OpenXM/src/kan96xx/Kan/gb.c	2003/07/30 09:00:52	1.7
+++ OpenXM/src/kan96xx/Kan/gb.c	2005/06/09 04:09:22	1.9
@@ -1,4 +1,4 @@
-/* $OpenXM: OpenXM/src/kan96xx/Kan/gb.c,v 1.6 2002/02/10 08:22:56 takayama Exp $ */
+/* $OpenXM: OpenXM/src/kan96xx/Kan/gb.c,v 1.8 2003/08/19 08:02:09 takayama Exp $ */
 /*  untabify on May 4, 2001 */
 #include <stdio.h>
 #include "datatype.h"
@@ -23,6 +23,8 @@ extern int UseCriterion2B;
 extern int Spairs;
 extern int Criterion2B, Criterion2F, Criterion2M;
 extern int AutoReduce;
+extern int TraceLift;
+extern struct ring *TraceLift_ringmod;
 static int MaxLength[DMAX];
 static int SpNumber[DMAX];
 
@@ -160,13 +162,14 @@ struct gradedPairs *updatePairs(grD,gt,gtGrade,t,grG)
   return(grD);
 }
 
-struct gradedPolySet *groebner_gen(f,needBack,needSyz,grP,countDown,forceReduction)
+struct gradedPolySet *groebner_gen(f,needBack,needSyz,grP,countDown,forceReduction,reduceOnly)
      struct arrayOfPOLY *f;
      int needBack;
      int needSyz;
      struct pair **grP;  /* if (needSyz), it is set. */
      int countDown;
      int forceReduction;
+     int reduceOnly;
 {
   int r;
   struct gradedPolySet *g;
@@ -192,8 +195,10 @@ struct gradedPolySet *groebner_gen(f,needBack,needSyz,
   extern struct ring *CurrentRingp;
   extern char *F_mpMult;
   struct ring *rp;
+  int first;
   int statisticsPL, statisticsCount;
 
+
   if (Statistics) {
     for (i=0; i<DMAX; i++) MaxLength[i] = SpNumber[i] = 0;
   }
@@ -216,9 +221,15 @@ struct gradedPolySet *groebner_gen(f,needBack,needSyz,
     g->polys[i] = newPolySet(INITSIZE);
   }
 
+  first = 1;
   for (i=0; i<r; i++) {
     gt = getArrayOfPOLY(f,i);
     if (gt ISZERO) { rp = CurrentRingp; } else { rp = gt->m->ringp; }
+	if (TraceLift && (!(gt ISZERO)) && first) {
+	  TraceLift_ringmod = newRingOverFp(rp,getPrime(TraceLift)); first = 0;
+	  if (KanGBmessage) printf("Prime number for the trace lift is %d.\n",
+							   TraceLift_ringmod->p);
+	}
     grade = -1; whereInG(g,gt,&grade,&indx,Sugar);
     if (KanGBmessage == 2) {
       printf("init=%s, ",POLYToString(head(gt),'*',1));
@@ -260,7 +271,8 @@ struct gradedPolySet *groebner_gen(f,needBack,needSyz,
     gj = g->polys[jg]->g[ji];
 
     Spairs++;
-    h = (*sp)(gi,gj);
+	if (reduceOnly && (!needSyz) && (!needBack)) h = spZero(); /* rd = 0 */
+	else h = (*sp)(gi,gj);
     rd = ppAddv(ppMult(h.a,gi),ppMult(h.b,gj));
 
     if (Statistics) {
@@ -400,7 +412,7 @@ struct gradedPolySet *groebner_gen(f,needBack,needSyz,
     printf("\n");
   }
 
-  if (AutoReduce) {
+  if (AutoReduce || reduceOnly) {
     toReducedBasis(g,needBack,needSyz);
   }