===================================================================
RCS file: /home/cvs/OpenXM_contrib2/asir2000/engine/Hgfs.c,v
retrieving revision 1.24
retrieving revision 1.30
diff -u -p -r1.24 -r1.30
--- OpenXM_contrib2/asir2000/engine/Hgfs.c	2002/09/30 06:13:07	1.24
+++ OpenXM_contrib2/asir2000/engine/Hgfs.c	2003/01/15 10:21:17	1.30
@@ -1,8 +1,10 @@
-/* $OpenXM: OpenXM_contrib2/asir2000/engine/Hgfs.c,v 1.23 2002/09/27 08:40:48 noro Exp $ */
+/* $OpenXM: OpenXM_contrib2/asir2000/engine/Hgfs.c,v 1.29 2002/11/22 08:44:57 noro Exp $ */
 
 #include "ca.h"
 #include "inline.h"
 
+int debug_sfbfctr;
+
 void lnfsf(int n,UM p0,UM p1,struct p_pair *list,UM np0,UM np1);
 void extractcoefbm(BM f,int dx,UM r);
 
@@ -16,7 +18,7 @@ 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;
@@ -79,6 +81,7 @@ void gensqfrsfum(UM p,struct oDUM *dc)
 {
 	int n,i,j,d,mod;
 	UM t,s,g,f,f1,b;
+	GFS u,v;
 
 	if ( (n = DEG(p)) == 1 ) {
 		dc[0].f = UMALLOC(DEG(p)); cpyum(p,dc[0].f); dc[0].n = 1;
@@ -117,8 +120,11 @@ void gensqfrsfum(UM p,struct oDUM *dc)
 				break;
 			else {
 				DEG(s) = DEG(t)/mod;
-				for ( j = 0; j <= DEG(t); j++ )
-					COEF(s)[j] = COEF(t)[j*mod];	
+				for ( j = 0; j <= DEG(t); j++ ) {
+					iftogfs(COEF(t)[j*mod],&u);
+					pthrootgfs(u,&v);
+					COEF(s)[j] = v?FTOIF(CONT(v)):0;
+				}
 				cpyum(s,b); d *= mod;
 			}
 		}
@@ -506,21 +512,21 @@ 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 +540,15 @@ 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;
@@ -604,10 +611,12 @@ void sfhensel(int count,P f,V x,int degbound,GFS *evp,
 
 	q = W_UMALLOC(dx);
 	rlist = MLALLOC(fn); rlist->n = fn; rlist->bound = bound;
-	fprintf(asir_out,"%d candidates\n",fn);
+	if ( debug_sfbfctr )
+		fprintf(asir_out,"%d candidates\n",fn);
 	init_eg(&eg_hensel);
 	for ( i = 0; i < fn-1; i++ ) {
-		fprintf(asir_out,"deg(fm) = %d, deg(gm[%d]) = %d\n",
+		if ( debug_sfbfctr )
+			fprintf(asir_out,"deg(fm) = %d, deg(gm[%d]) = %d\n",
 			DEG(fm),i,DEG(gm[i]));
 		init_eg(&eg_hensel_t);
 		get_eg(&tmp0);
@@ -619,11 +628,15 @@ void sfhensel(int count,P f,V x,int degbound,GFS *evp,
 		cpyum(hm,fm);
 		get_eg(&tmp1); add_eg(&eg_hensel_t,&tmp0,&tmp1);
 		add_eg(&eg_hensel,&tmp0,&tmp1);
-		print_eg("Hensel",&eg_hensel_t);
+		if ( debug_sfbfctr) {
+			print_eg("Hensel",&eg_hensel_t);
+			fprintf(asir_out,"\n");
+		}
+	}
+	if ( debug_sfbfctr) {
+		print_eg("Hensel total",&eg_hensel);
 		fprintf(asir_out,"\n");
 	}
-	print_eg("Hensel total",&eg_hensel);
-	fprintf(asir_out,"\n");
 	/* finally, fl must be the lift of gm[fn-1] */
 	rlist->c[i] = fl;
 
@@ -640,20 +653,20 @@ 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,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);
@@ -669,7 +682,7 @@ int sfberle(VL vl,P f,int count,GFS *ev,DCP *dcp)
 			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;
@@ -756,9 +769,11 @@ void sfhenmain2(BM f,UM g0,UM h0,int dy,BM *gp)
 	wa = W_UMALLOC(2*dx); wb = W_UMALLOC(2*dx);  /* XXX */
 	eucsfum(w1,w2,wa,wb);
 
-	fprintf(stderr,"dy=%d\n",dy);
+	if ( debug_sfbfctr)
+		fprintf(stderr,"dy=%d\n",dy);
 	for ( k = 1; k <= dy; k++ ) {
-		fprintf(stderr,".");
+		if ( debug_sfbfctr)
+			fprintf(stderr,".");
 
 		/* at this point, f = gk*hk mod y^k */
 
@@ -814,13 +829,104 @@ void sfhenmain2(BM f,UM g0,UM h0,int dy,BM *gp)
 		cpyum(wg1,COEF(gk)[k]);
 		cpyum(wh1,COEF(hk)[k]);
 	}
-	fprintf(stderr,"\n");
+	if ( debug_sfbfctr)
+		fprintf(stderr,"\n");
 	*gp = gk;
 	DEG(f) = dy;
 	for ( i = 0; i <= dy; i++ )
 		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;
+	
+	if ( debug_sfbfctr)
+		fprintf(stderr,"dy=%d\n",dy);
+	for ( k = 1; k <= dy; k++ ) {
+		if ( debug_sfbfctr)
+			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]);
+	}
+	if ( debug_sfbfctr)
+		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)
@@ -990,7 +1096,7 @@ 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 ) {
@@ -1013,6 +1119,33 @@ 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)
@@ -1085,10 +1218,11 @@ void sfdtest(P f,ML list,V x,V y,DCP *dcp)
 		}
 	}
 
-	fprintf(stderr,"np = %d\n",np);
+	if ( debug_sfbfctr)
+		fprintf(stderr,"np = %d\n",np);
 	dtok = 0;
 	for ( g = f, k = 1, dcf = dcf0 = 0, win[0] = 1, --np, z = 0; ; z++ ) {
-		if ( !(z % 1000) ) fprintf(stderr,".");
+		if ( debug_sfbfctr && !(z % 1000) ) fprintf(stderr,".");
 		dt = sfdegtest(dy,bound,d1c,k,win);
 		if ( dt )
 			dtok++;
@@ -1153,7 +1287,8 @@ void sfdtest(P f,ML list,V x,V y,DCP *dcp)
 				for ( i = 0, ++k; i < k; i++ ) 
 					win[i] = i + 1;
 	}
-	fprintf(stderr,"total %d, omitted by degtest %d\n",z,z-dtok);
+	if ( debug_sfbfctr )
+		fprintf(stderr,"total %d, omitted by degtest %d\n",z,z-dtok);
 	NEXTDC(dcf0,dcf); COEF(dcf) = g;
 	DEG(dcf) = ONE; NEXT(dcf) = 0; *dcp = dcf0;
 }