===================================================================
RCS file: /home/cvs/OpenXM_contrib2/asir2000/engine/Hgfs.c,v
retrieving revision 1.14
retrieving revision 1.17
diff -u -p -r1.14 -r1.17
--- OpenXM_contrib2/asir2000/engine/Hgfs.c	2001/07/03 01:41:25	1.14
+++ OpenXM_contrib2/asir2000/engine/Hgfs.c	2001/09/03 07:01:06	1.17
@@ -1,4 +1,4 @@
-/* $OpenXM: OpenXM_contrib2/asir2000/engine/Hgfs.c,v 1.13 2001/06/29 09:08:53 noro Exp $ */
+/* $OpenXM: OpenXM_contrib2/asir2000/engine/Hgfs.c,v 1.16 2001/09/03 01:04:26 noro Exp $ */
 
 #include "ca.h"
 
@@ -614,7 +614,7 @@ ML *listp;
 	/* f(x,y) -> f(x,y+ev) */
 	fl = BMALLOC(dx,dy);
 	ptosfbm(dy,f,fl);
-	shiftsfbm(fl,FTOIF(CONT(ev)));
+	if ( ev ) shiftsfbm(fl,FTOIF(CONT(ev)));
 
 	/* sf = f(x+ev) */
 	sfbmtop(fl,x,y,&sf);
@@ -1028,13 +1028,15 @@ DCP *dcp;
 		return;
 	}
 	sfdtest(sf,list,x,y,&dc);
-	dx = getdeg(x,sf);
-	dy = getdeg(y,sf);
-	W_BMALLOC(dx,dy,fl);
-	for ( dct = dc; dct; dct = NEXT(dct) ) {
-		ptosfbm(dy,COEF(dct),fl);
-		shiftsfbm(fl,_chsgnsf(FTOIF(CONT(ev))));
-		sfbmtop(fl,x,y,&COEF(dct));
+	if ( ev ) {
+		dx = getdeg(x,sf);
+		dy = getdeg(y,sf);
+		W_BMALLOC(dx,dy,fl);
+		for ( dct = dc; dct; dct = NEXT(dct) ) {
+			ptosfbm(dy,COEF(dct),fl);
+			shiftsfbm(fl,_chsgnsf(FTOIF(CONT(ev))));
+			sfbmtop(fl,x,y,&COEF(dct));
+		}
 	}
 	*dcp = dc;
 }
@@ -1367,4 +1369,51 @@ P *qp;
 	if ( j >= 0 )
 		return 0;
 	sfbmtop(ql,x,y,qp);
+}
+
+/* XXX generate an irreducible poly of degree n */
+
+extern int current_gfs_q1;
+
+void generate_defpoly_sfum(n,dp)
+int n;
+UM *dp;
+{
+	UM r,dr,t,g;
+	UM *f;
+	int *c,*w;
+	int max,i,j;
+
+	*dp = r = UMALLOC(n);
+	DEG(r) = n;
+	c = COEF(r);
+	c[n] = _onesf();
+	max = current_gfs_q1;
+	w = (int *)ALLOCA(n*sizeof(int));
+	bzero(w,n*sizeof(int));
+
+	dr = W_UMALLOC(n); t = W_UMALLOC(n); g = W_UMALLOC(n);
+	f = (UM *)ALLOCA((n+1)*sizeof(UM));
+	while ( 1 ) {
+		for ( i = 0; i < n && w[i] == max; i++ );
+		if ( i == n ) {
+			/* XXX cannot happen */
+			error("generate_defpoly_sfum : cannot happen");
+		}
+		for ( j = 0; j < i; j++ )
+			w[j] = 0;
+		w[i]++;
+		for ( i = 0; i < n; i++ )
+			c[i] = w[i]?FTOIF(w[i]-1):0;
+		if ( !c[0] )
+			continue;
+		diffsfum(r,dr); cpyum(r,t); gcdsfum(t,dr,g);
+		if ( DEG(g) > 0 )
+			continue;
+
+		czsfum(r,f);
+		for ( i = 0; f[i]; i++ );
+		if ( i == 1 )
+			return;
+	}
 }