===================================================================
RCS file: /home/cvs/OpenXM_contrib2/asir2000/engine/gfs.c,v
retrieving revision 1.9
retrieving revision 1.12
diff -u -p -r1.9 -r1.12
--- OpenXM_contrib2/asir2000/engine/gfs.c	2001/10/09 01:36:12	1.9
+++ OpenXM_contrib2/asir2000/engine/gfs.c	2002/09/27 08:40:49	1.12
@@ -45,9 +45,10 @@
  * DEVELOPER SHALL HAVE NO LIABILITY IN CONNECTION WITH THE USE,
  * PERFORMANCE OR NON-PERFORMANCE OF THE SOFTWARE.
  *
- * $OpenXM: OpenXM_contrib2/asir2000/engine/gfs.c,v 1.8 2001/06/29 09:08:53 noro Exp $
+ * $OpenXM: OpenXM_contrib2/asir2000/engine/gfs.c,v 1.11 2002/09/27 04:24:04 noro Exp $
 */
 #include "ca.h"
+#include "inline.h"
 
 /* q = p^n */
 
@@ -66,6 +67,10 @@ struct prim_root_info {
 	int prim_root;
 };
 
+/* if p >= SF_THRESHOLD, usual representation is used */
+
+#define SF_THRESHOLD 16384
+
 struct prim_root_info prim_root_info_tab[] = {
 {2,1,0,0}, {2,2,7,2}, {2,3,11,2}, {2,4,19,2}, {2,5,37,2}, {2,6,67,2},
 {2,7,131,2}, {2,8,283,3}, {2,9,515,7}, {2,10,1033,2}, {2,11,2053,2},
@@ -491,6 +496,19 @@ void setmod_sf(int p,int n)
 	int r,i,q1,q,t,t1;
 	UM dp;
 
+	if ( p >= SF_THRESHOLD ) {
+		if ( n > 1 )
+			error("setmod_ff : p^n is too large");
+		current_gfs_p = p;
+		current_gfs_q = p;
+		current_gfs_q1 = p-1;
+		current_gfs_ext = 0;
+		current_gfs_ntoi = 0;
+		current_gfs_iton = 0;
+		current_gfs_plus1 = 0;
+		return;
+	}
+
 	for ( i = 0, q = 1; i < n; i++ )
 		q *= p;
 	dp = UMALLOC(n);
@@ -639,17 +657,19 @@ int mulremum_enc(int p,int n,UM dp,int a,int b)
 	return r;
 }
 
+/* sigma : alpha -> alpha^q */
+
 void gfs_galois_action(GFS a,Q e,GFS *c)
 {
-	Q p;
+	Q q;
 	int i,k;
 	GFS t,s;
 
 	t = a;
 	k = QTOS(e);
-	STOQ(current_gfs_p,p);
+	STOQ(current_gfs_q,q);
 	for ( i = 0; i < k; i++ ) {
-		pwrgfs(t,p,&s); t = s;
+		pwrgfs(t,q,&s); t = s;
 	}
 	*c = t;
 }
@@ -668,33 +688,64 @@ void gfs_embed(GFS z,int k,int pm,GFS *c)
 	}
 }
 
+/* 0 <= index <= q-1 */
+
+void indextogfs(int index, GFS *c)
+{
+	if ( index == 0 )
+		*c = 0;
+	else if ( index >= current_gfs_q )
+		error("indextogfs : exhausted");
+	else if ( !current_gfs_ntoi ) {
+		MKGFS(index,*c);
+	} else {
+		MKGFS(index-1,*c);
+	}
+}
+
+void itogfs(int n, GFS *c)
+{
+	n = _itosf(n);
+	if ( !n )
+		*c = 0;
+	else {
+		n = IFTOF(n);
+		MKGFS(n,*c);
+	}
+}
+
+void iftogfs(int n, GFS *c)
+{
+	if ( !n )
+		*c = 0;
+	else {
+		MKGFS(IFTOF(n),*c);
+	}
+}
+
 void qtogfs(Q a,GFS *c)
 {
 	int s;
 
 	s = QTOS(a)%current_gfs_q;
-	if ( s < 0 )
-		s += current_gfs_q;
-	if ( !s )
-		*c = 0;
-	else
-		MKGFS(current_gfs_ntoi[s],*c);	
+	itogfs(s,c);
 }
 
 void mqtogfs(MQ a,GFS *c)
 {
 	if ( !a )
 		*c = 0;
-	else {
-		MKGFS(current_gfs_ntoi[CONT(a)],*c);	
-	}
+	else
+		itogfs(CONT(a),c);
 }
 
 void gfstomq(GFS a,MQ *c)
 {
 	if ( !a )
 		*c = 0;
-	else {
+	else if ( !current_gfs_ntoi ) {
+		UTOMQ(CONT(a),*c);
+	} else {
 		UTOMQ(current_gfs_iton[CONT(a)],*c);
 	}
 }
@@ -726,8 +777,18 @@ void addgfs(GFS a,GFS b,GFS *c)
 		*c = b;
 	else if ( !b )
 		*c = a;
-	else {
+	else if ( !current_gfs_ntoi ) {
 		ai = CONT(a); bi = CONT(b);
+		ci = ai+bi-current_gfs_q;
+		if ( ci == 0 )
+			*c = 0;
+		else {
+			if ( ci < 0 )
+				ci += current_gfs_q;	
+			MKGFS(ci,*c);
+		}
+	} else {
+		ai = CONT(a); bi = CONT(b);
 		if ( ai > bi ) {
 			/* tab[ai]+tab[bi] = tab[bi](tab[ai-bi]+1) */
 			ci = current_gfs_plus1[ai-bi];
@@ -770,14 +831,18 @@ void subgfs(GFS a,GFS b,GFS *c)
 
 void mulgfs(GFS a,GFS b,GFS *c)
 {
-	int ai;
+	int ai,bi,ci;
 	GFS z;
 
 	ntogfs((Obj)a,&z); a = z;
 	ntogfs((Obj)b,&z); b = z;
 	if ( !a || !b )
 		*c = 0;
-	else {
+	else if ( !current_gfs_ntoi ) {
+		ai = CONT(a); bi = CONT(b);
+		DMAR(ai,bi,0,current_gfs_q,ci);
+		MKGFS(ci,*c);
+	} else {
 		ai = CONT(a) + CONT(b);
 		if ( ai >= current_gfs_q1 )
 			ai -= current_gfs_q1;
@@ -787,7 +852,7 @@ void mulgfs(GFS a,GFS b,GFS *c)
 
 void divgfs(GFS a,GFS b,GFS *c)
 {
-	int ai;
+	int ai,bi,ci;
 	GFS z;
 
 	ntogfs((Obj)a,&z); a = z;
@@ -796,7 +861,11 @@ void divgfs(GFS a,GFS b,GFS *c)
 		error("divgfs : division by 0");
 	else if ( !a )
 		*c = 0;
-	else {
+	else if ( !current_gfs_ntoi ) {
+		ai = CONT(a); bi = invm(CONT(b),current_gfs_q);
+		DMAR(ai,bi,0,current_gfs_q,ci);
+		MKGFS(ci,*c);
+	} else {
 		ai = CONT(a) - CONT(b);
 		if ( ai < 0 )
 			ai += current_gfs_q1;
@@ -812,7 +881,10 @@ void chsgngfs(GFS a,GFS *c)
 	ntogfs((Obj)a,&z); a = z;
 	if ( !a )
 		*c = 0;
-	else if ( current_gfs_q1&1 )
+	else if ( !current_gfs_ntoi ) {
+		ai = current_gfs_q - CONT(a);
+		MKGFS(ai,*c);
+	} else if ( current_gfs_q1&1 )
 		*c = a;
 	else {	
 		/* r^((q-1)/2) = -1 */
@@ -827,21 +899,25 @@ void pwrgfs(GFS a,Q b,GFS *c)
 {
 	N an,tn,rn;
 	GFS t,s,z;
+	int ai;
 
 	ntogfs((Obj)a,&z); a = z;
 	if ( !b )
-		MKGFS(0,*c);
+		itogfs(1,c);
 	else if ( !a )
 		*c = 0;
-	else {
+	else if ( !current_gfs_ntoi) {
+		ai = pwrm(current_gfs_q,CONT(a),QTOS(b));
+		MKGFS(ai,*c);
+	} else {
 		STON(CONT(a),an); muln(an,NM(b),&tn);
 		STON(current_gfs_q1,an); remn(tn,an,&rn);
 		if ( !rn )
-			MKGFS(0,*c);
+			itogfs(1,c);
 		else if ( SGN(b) > 0 )
 			MKGFS(BD(rn)[0],*c);
 		else {
-			MKGFS(0,t);
+			itogfs(1,&t);
 			MKGFS(BD(rn)[0],s);
 			divgfs(t,s,c);
 		}
@@ -875,13 +951,7 @@ void randomgfs(GFS *r)
 	if ( !current_gfs_q1 )
 		error("addgfs : current_gfs_q is not set");
 	t = mt_genrand()%current_gfs_q;
-	if ( !t )
-		*r = 0;
-	else {
-		if ( t == (unsigned int)current_gfs_q1 )
-			t = 0;
-		MKGFS(t,*r);
-	}
+	indextogfs(t,r);
 }
 
 /* arithmetic operations for 'immediate values of GFS */
@@ -894,6 +964,18 @@ int _addsf(int a,int b)
 		return a;
 
 	a = IFTOF(a); b = IFTOF(b);
+
+	if ( !current_gfs_ntoi ) {
+		a = a+b-current_gfs_q;
+		if ( a == 0 )
+			return 0;
+		else { 
+			if ( a < 0 )
+				a += current_gfs_q;	
+			return FTOIF(a);
+		}
+	}
+
 	if ( a > b ) {
 		/* tab[a]+tab[b] = tab[b](tab[a-b]+1) */
 		a = current_gfs_plus1[a-b];
@@ -923,7 +1005,10 @@ int _chsgnsf(int a)
 {
 	if ( !a )
 		return 0;
-	else if ( current_gfs_q1&1 )
+	else if ( !current_gfs_ntoi ) {
+		a = current_gfs_q-IFTOF(a);
+		return FTOIF(a);
+	} else if ( current_gfs_q1&1 )
 		return a;
 	else {	
 		/* r^((q-1)/2) = -1 */
@@ -947,9 +1032,15 @@ int _subsf(int a,int b)
 
 int _mulsf(int a,int b)
 {
+	int c;
+
 	if ( !a || !b )
 		return 0;
-	else {
+	else if ( !current_gfs_ntoi ) {
+		a = IFTOF(a); b = IFTOF(b);
+		DMAR(a,b,0,current_gfs_q,c);
+		return FTOIF(c);
+	} else {
 		a = IFTOF(a) + IFTOF(b);
 		if ( a >= current_gfs_q1 )
 			a -= current_gfs_q1;
@@ -963,6 +1054,9 @@ int _invsf(int a)
 		error("_invsf : division by 0");
 		/* NOTREACHED */
 		return -1;
+	} else if ( !current_gfs_ntoi ) {
+		a = invm(IFTOF(a),current_gfs_q);
+		return FTOIF(a);
 	} else {
 		a = current_gfs_q1 - IFTOF(a);
 		return FTOIF(a);
@@ -971,10 +1065,17 @@ int _invsf(int a)
 
 int _divsf(int a,int b)
 {
+	int c;
+
 	if ( !b ) {
 		error("_divsf : division by 0");
 		/* NOTREACHED */
 		return -1;
+	} else if ( !current_gfs_ntoi ) {
+		b = invm(IFTOF(b),current_gfs_q);
+		a = IFTOF(a);
+		DMAR(a,b,0,current_gfs_q,c);
+		return FTOIF(c);
 	} else if ( !a )
 		return 0;
 	else {
@@ -995,9 +1096,11 @@ int _pwrsf(int a,int b)
 		return _onesf();
 	else if ( !a )
 		return 0;
-	else {
-		a = IFTOF(a);
-		MKGFS(a,at);
+	if ( !current_gfs_ntoi ) {
+		a = pwrm(current_gfs_q,IFTOF(a),b);
+		return FTOIF(a);
+	} else {
+		iftogfs(a,&at);
 		STOQ(b,bt);
 		pwrgfs(at,bt,&ct);
 		c = CONT(ct);
@@ -1007,7 +1110,7 @@ int _pwrsf(int a,int b)
 
 int _onesf()
 {
-	return FTOIF(0);
+	return !current_gfs_ntoi ? FTOIF(1) : FTOIF(0);
 }
 
 int _itosf(int n)
@@ -1017,7 +1120,7 @@ int _itosf(int n)
 	n %= current_gfs_p;
 	if ( !n )
 		return 0;
-	i = current_gfs_ntoi[n];
+	i = !current_gfs_ntoi ? n : current_gfs_ntoi[n];
 	i = FTOIF(i);
 	if ( n < 0 )
 		i = _chsgnsf(i);
@@ -1026,18 +1129,18 @@ int _itosf(int n)
 
 int _isonesf(int a)
 {
-	return a == FTOIF(0);
+	return a == _onesf();
 }
 
 int _randomsf()
 {
 	int t;
 
-	t = (int) (mt_genrand() % current_gfs_q1);
-	if ( !t )
-		return 0;
+	t = (int) (mt_genrand() % current_gfs_q);
+	if ( !current_gfs_ntoi )
+		return t ? FTOIF(t) : 0;
 	else
-		return FTOIF(t);
+		return t!=current_gfs_q1 ? FTOIF(t) : 0;
 }
 
 int field_order_sf()
@@ -1052,5 +1155,8 @@ int characteristic_sf()
 
 int extdeg_sf()
 {
-	return UDEG(current_gfs_ext);
+	if ( !current_gfs_ext )
+		return 1;
+	else
+		return UDEG(current_gfs_ext);
 }