===================================================================
RCS file: /home/cvs/OpenXM_contrib2/asir2000/engine/Hgfs.c,v
retrieving revision 1.22
retrieving revision 1.28
diff -u -p -r1.22 -r1.28
--- OpenXM_contrib2/asir2000/engine/Hgfs.c	2002/09/27 04:24:04	1.22
+++ OpenXM_contrib2/asir2000/engine/Hgfs.c	2002/11/22 07:32:10	1.28
@@ -1,4 +1,4 @@
-/* $OpenXM: OpenXM_contrib2/asir2000/engine/Hgfs.c,v 1.21 2001/11/19 00:57:11 noro Exp $ */
+/* $OpenXM: OpenXM_contrib2/asir2000/engine/Hgfs.c,v 1.27 2002/11/01 05:43:35 noro Exp $ */
 
 #include "ca.h"
 #include "inline.h"
@@ -16,7 +16,7 @@ int comp_dum(DUM a,DUM b)
 		return 0;
 }
 
-void fctrsf(P p,DCP *dcp)
+void ufctrsf(P p,DCP *dcp)
 {
 	int n,i,j,k;
 	DCP dc,dc0;
@@ -506,21 +506,21 @@ void canzassf(UM f,int d,UM *r)
 
 /* Hensel related functions */
 
-int sfberle(VL,P,int,GFS *,DCP *);
+int sfberle(V,V,P,int,GFS *,DCP *);
 void sfgcdgen(P,ML,ML *);
 void sfhenmain2(BM,UM,UM,int,BM *);
 void ptosfbm(int,P,BM);
+void sfhensel(int count,P f,V x,V y,int degbound,GFS *evp,P *sfp,ML *listp);
 
 /* f = f(x,y) */
 
-void sfhensel(int count,P f,V x,int degbound,GFS *evp,P *sfp,ML *listp)
+void sfhensel(int count,P f,V x,V y,int degbound,GFS *evp,P *sfp,ML *listp)
 {
 	int i;
 	int fn;
 	ML rlist;
 	BM fl;
 	VL vl,nvl;
-	V y;
 	int dx,dy,bound;
 	GFS ev;
 	P f1,t,c,sf;
@@ -534,14 +534,15 @@ void sfhensel(int count,P f,V x,int degbound,GFS *evp,
 		reordvar(vl,x,&nvl); reorderp(nvl,vl,f,&f1);
 		vl = nvl; f = f1;
 	}
-	y = vl->next->v;
+	if ( vl->next )
+		y = vl->next->v;
 	dx = getdeg(x,f);
 	dy = getdeg(y,f);
 	if ( dx == 1 ) {
 		*listp = rlist = MLALLOC(1); rlist->n = 1; rlist->c[0] = 0;
 		return;
 	}
-	fn = sfberle(vl,f,count,&ev,&dc);
+	fn = sfberle(x,y,f,count,&ev,&dc);
 	if ( fn <= 1 ) {
 		/* fn == 0 => short of evaluation points */
 		*listp = rlist = MLALLOC(1); rlist->n = fn; rlist->c[0] = 0;
@@ -640,36 +641,36 @@ void sfhensel(int count,P f,V x,int degbound,GFS *evp,
 
 /* main variable of f = x */
 
-int sfberle(VL vl,P f,int count,GFS *ev,DCP *dcp)
+int sfberle(V x,V y,P f,int count,GFS *ev,DCP *dcp)
 {
 	UM wf,wf1,wf2,wfs,gcd;
 	int fn,n;
 	GFS m,fm;
 	DCP dc,dct,dc0;
-	VL nvl;
-	V x,y;
+	VL vl;
 	P lc,lc0,f0;
 	Obj obj;
-	int j,q1,index,i;
+	int j,q,index,i;
 
-	clctv(vl,f,&nvl); vl = nvl;
-	x = vl->v; y = vl->next->v;
+	NEWVL(vl); vl->v = x;
+	NEWVL(NEXT(vl)); NEXT(vl)->v = y;
+	NEXT(NEXT(vl)) =0;
 	simp_ff((Obj)f,&obj); f = (P)obj;
 	n = QTOS(DEG(DC(f)));
 	wf = W_UMALLOC(n); wf1 = W_UMALLOC(n); wf2 = W_UMALLOC(n);
 	wfs = W_UMALLOC(n); gcd = W_UMALLOC(n);
-	q1 = field_order_sf()-1;
+	q = field_order_sf();
 	lc = DC(f)->c;
 	for ( j = 0, fn = n + 1, index = 0; 
-		index < q1 && j < count && fn > 1; index++ ) {
-		MKGFS(index,m);
+		index < q && j < count && fn > 1; index++ ) {
+		indextogfs(index,&m);
 		substp(vl,lc,y,(P)m,&lc0);
 		if ( lc0 ) {
 			substp(vl,f,y,(P)m,&f0);
 			ptosfum(f0,wf); cpyum(wf,wf1); 
 			diffsfum(wf1,wf2); gcdsfum(wf1,wf2,gcd);
 			if ( DEG(gcd) == 0 ) {
-				fctrsf(f0,&dc);
+				ufctrsf(f0,&dc);
 				for ( dct = NEXT(dc), i = 0; dct; dct = NEXT(dct), i++ );
 				if ( i < fn ) {
 					dc0 = dc; fn = i; fm = m;
@@ -678,7 +679,7 @@ int sfberle(VL vl,P f,int count,GFS *ev,DCP *dcp)
 			}
 		}
 	}
-	if ( index == q1 )
+	if ( index == q )
 		return 0;
 	else if ( fn == 1 )
 		return 1;
@@ -821,6 +822,93 @@ void sfhenmain2(BM f,UM g0,UM h0,int dy,BM *gp)
 		cpyum(COEF(hk)[i],COEF(f)[i]);
 }
 
+/* a0*g+b0*h = 1 mod y -> a*g+b*h = 1 mod y^(dy+1) */
+
+void sfexgcd_by_hensel(BM g,BM h,int dy,BM *ap,BM *bp)
+{
+	int i,k;
+	int dx;
+	UM wt,wa,wb,q,w1,w2,ws;
+	UM wc,wd,we,wz,wa1,wb1;
+	BM wz0,wz1;
+	int dg,dh;
+	BM a,b,c;
+
+	dg = degbm(g);
+	dh = degbm(h);
+	dx = dg+dh;
+
+	a = BMALLOC(dh,dy);
+	b = BMALLOC(dg,dy);
+	/* c holds a*g+b*h-1 */
+	c = BMALLOC(dg+dh,dy);
+
+	W_BMALLOC(dx,dy,wz0); W_BMALLOC(dx,dy,wz1);
+
+	wt = W_UMALLOC(dx); ws = W_UMALLOC(dx); q = W_UMALLOC(2*dx);
+	wa1 = W_UMALLOC(2*dx); wb1 = W_UMALLOC(2*dx);
+	wc = W_UMALLOC(2*dx); wd = W_UMALLOC(2*dx);
+	we = W_UMALLOC(2*dx); wz = W_UMALLOC(2*dx);
+
+	/* compute wa,wb s.t. wa*g0+wb*h0 = 1 mod y */
+	w1 = W_UMALLOC(dg); cpyum(COEF(g)[0],w1);
+	w2 = W_UMALLOC(dh); cpyum(COEF(h)[0],w2);
+	wa = W_UMALLOC(2*dx); wb = W_UMALLOC(2*dx);  /* XXX */
+	eucsfum(w1,w2,wa,wb);
+	cpyum(wa,COEF(a)[0]); cpyum(wb,COEF(b)[0]);
+	
+	/* initialize c to a*g+b*h-1 */
+	mulsfbm(a,g,c); mulsfbm(b,h,wz0); addtosfbm(wz0,c);
+	COEF(COEF(c)[0])[0] = 0;
+	
+	fprintf(stderr,"dy=%d\n",dy);
+	for ( k = 1; k <= dy; k++ ) {
+		fprintf(stderr,".");
+
+		/* at this point, a*g+b*h = 1 mod y^k, c = a*g+b*h-1 */
+
+		/* wt = -((a*g+b*h-1)/y^k) */
+		cpyum(COEF(c)[k],wt);
+		for ( i = DEG(wt); i >= 0; i-- )
+			COEF(wt)[i] = _chsgnsf(COEF(wt)[i]);
+		
+		/* compute wa1,wb1 s.t. wa1*g0+wb1*h0 = wt */
+		mulsfum(wa,wt,wa1); DEG(wa1) = divsfum(wa1,COEF(h)[0],q);
+		mulsfum(wa1,COEF(g)[0],wc); subsfum(wt,wc,wd); 
+		DEG(wd) = divsfum(wd,COEF(h)[0],wb1);
+
+		/* c += ((wa1*g+wb1*h)*y^k mod y^(dy+1) */
+		/* wz0 = wa1*y^k */
+		clearbm(dx,wz0);
+		cpyum(wa1,COEF(wz0)[k]);
+
+		/* wz1 = wz0*g mod y^(dy+1) */
+		clearbm(dx,wz1);
+		mulsfbm(g,wz0,wz1);
+		/* c += wz1 */
+		addtosfbm(wz1,c);
+
+		/* wz0 = wb1*y^k */
+		clearbm(dx,wz0);
+		cpyum(wb1,COEF(wz0)[k]);
+
+		/* wz1 = wz0*h mod y^(dy+1) */
+		clearbm(dx,wz1);
+		mulsfbm(h,wz0,wz1);
+		/* c += wz1 */
+		addtosfbm(wz1,c);
+
+		/* a += wa1*y^k, b += wb1*y^k */
+		cpyum(wa1,COEF(a)[k]);
+		cpyum(wb1,COEF(b)[k]);
+	}
+	fprintf(stderr,"\n");
+	DEG(a) = dy;
+	DEG(b) = dy;
+	*ap = a;
+	*bp = b;
+}
+
 /* fl->c[i] = coef_y(f,i) */
 
 void ptosfbm(int dy,P f,BM fl)
@@ -865,7 +953,7 @@ void sfbmtop(BM f,V x,V y,P *fp)
 			if ( DEG(c[j]) >= i && (a = COEF(c[j])[i]) ) {
 				NEWDC(dct);
 				STOQ(j,DEG(dct));
-				MKGFS(IFTOF(a),b);
+				iftogfs(a,&b);
 				COEF(dct) = (P)b;
 				NEXT(dct) = dc;
 				dc = dct;
@@ -898,12 +986,8 @@ void sfsqfr(P f,DCP *dcp)
 		NEWDC(dc); DEG(dc) = ONE; COEF(dc) = f; NEXT(dc) = 0; *dcp = dc;
 	} else if ( !NEXT(vl) )
 		sfusqfr(f,dcp);
-#if 0
-	else if ( !NEXT(NEXT(vl)) )
-		sfbsqfr(f,vl->v,NEXT(vl)->v,dcp);
-#endif
 	else
-		error("sfsqfr : not implemented yet");
+		sqfrsf(f,dcp);
 }
 
 void sfusqfr(P f,DCP *dcp)
@@ -934,6 +1018,7 @@ void sfusqfr(P f,DCP *dcp)
 	*dcp = dct;
 }
 
+#if 0
 void sfbsqfrmain(P f,V x,V y,DCP *dcp)
 {
 	/* XXX*/
@@ -977,6 +1062,7 @@ void sfbsqfr(P f,V x,V y,DCP *dcp)
 		*dcp = dcx;
 	}
 }
+#endif
 
 void sfdtest(P,ML,V,V,DCP *);
 
@@ -992,7 +1078,7 @@ void sfbfctr(P f,V x,V y,int degbound,DCP *dcp)
 	int dx,dy;
 
 	/* sf(x) = f(x+ev) = list->c[0]*list->c[1]*... */
-	sfhensel(5,f,x,degbound,&ev,&sf,&list);
+	sfhensel(5,f,x,y,degbound,&ev,&sf,&list);
 	if ( list->n == 0 )
 		error("sfbfctr : short of evaluation points");
 	else if ( list->n == 1 ) {
@@ -1015,6 +1101,33 @@ void sfbfctr(P f,V x,V y,int degbound,DCP *dcp)
 	*dcp = dc;
 }
 
+/* returns shifted f, shifted factors and the eval pt */
+
+void sfbfctr_shift(P f,V x,V y,int degbound,GFS *evp,P *sfp,DCP *dcp)
+{
+	ML list;
+	P sf;
+	GFS ev;
+	DCP dc,dct;
+	int dx,dy;
+
+	/* sf(x) = f(x+ev) = list->c[0]*list->c[1]*... */
+	sfhensel(5,f,x,y,degbound,&ev,&sf,&list);
+	if ( list->n == 0 )
+		error("sfbfctr_shift : short of evaluation points");
+	else if ( list->n == 1 ) {
+		/* f is irreducible */
+		NEWDC(dc); DEG(dc) = ONE; COEF(dc) = f; NEXT(dc) = 0;
+		*evp = 0;
+		*sfp = f;
+		*dcp = dc;
+	} else {
+		sfdtest(sf,list,x,y,dcp);
+		*evp = ev;
+		*sfp = sf;
+	}
+}
+
 /* f = f(x,y) = list->c[0]*list->c[1]*... mod y^(list->bound+1) */
 
 void sfdtest(P f,ML list,V x,V y,DCP *dcp)
@@ -1322,7 +1435,7 @@ void cont_pp_sfp(VL vl,P f,P *cp,P *fp)
 	y = vl->next->v;
 	d = getdeg(y,f);
 	if ( d == 0 ) {
-		MKGFS(0,g);
+		itogfs(1,&g);
 		*cp = (P)g;
 		*fp = f;  /* XXX */
 	} else {