Fix sign error for wildcard powers of dotproducts involving negative vectors

Fixes #544

Author: jodavies

check/fixes.frm

@@ -3048,6 +3048,91 @@ P F;
 assert succeeded?
 assert result("F") =~ expr("0")
 *--#] Issue525 :
+*--#[ Issue544 :
+#-
+Off Statistics;
+
+Symbol x;
+Vector D,p,q;
+CFunction tag;
+CFunction f,g,h,i,j,k,l,m;
+CFunction F,G,H,I,J,K,L,M;
+
+#define N "3"
+
+Local test =
+	#do i = -`N',`N'
+		+ f(p,`i')
+		+ f(-q,`i')
+		+ f(p,q,`i')
+		+ f(-p,q,`i')
+		+ f(p,-q,`i')
+		+ f(-p,-q,`i')
+	#enddo
+	;
+
+* Use tags to make sure the cancellation is unique
+Identify f(?a) =
+	+ (f(?a) - F(?a)) * tag(f,?a)
+	+ (g(?a) - G(?a)) * tag(g,?a)
+	+ (h(?a) - H(?a)) * tag(h,?a)
+	+ (i(?a) - I(?a)) * tag(i,?a)
+	+ (j(?a) - J(?a)) * tag(j,?a)
+	+ (k(?a) - K(?a)) * tag(k,?a)
+	+ (l(?a) - L(?a)) * tag(l,?a)
+	+ (m(?a) - M(?a)) * tag(m,?a)
+	;
+.sort
+
+Identify f(p?,x?) = D.p^x;
+Identify f(p?,q?,x?) = p.q^x;
+Identify g(p?,x?) = D.p^-x;
+Identify g(p?,q?,x?) = p.q^-x;
+
+Identify h(p?,x?) = (D.p)^x;
+Identify h(p?,q?,x?) = (p.q)^x;
+Identify i(p?,x?) = D.p^(x);
+Identify i(p?,q?,x?) = p.q^(x);
+
+* And with - signs on the pattern vector:
+Identify j(-p?,x?) = D.p^x;
+Identify j(-p?,-q?,x?) = p.q^x;
+Identify k(-p?,x?) = D.p^-x;
+Identify k(-p?,-q?,x?) = p.q^-x;
+
+Identify l(-p?,x?) = (D.p)^x;
+Identify l(-p?,-q?,x?) = (p.q)^x;
+Identify m(-p?,x?) = D.p^(x);
+Identify m(-p?,-q?,x?) = p.q^(x);
+
+* Cancel all terms, with no pattern for the power
+#do i = -`N',`N'
+	Identify F(p?,`i') = D.p^`i';
+	Identify F(p?,q?,`i') = p.q^`i';
+	Identify G(p?,`i') = D.p^-`i';
+	Identify G(p?,q?,`i') = p.q^-`i';
+
+	Identify H(p?,`i') = (D.p)^`i';
+	Identify H(p?,q?,`i') = (p.q)^`i';
+	Identify I(p?,`i') = D.p^(`i');
+	Identify I(p?,q?,`i') = p.q^(`i');
+
+	Identify J(-p?,`i') = D.p^`i';
+	Identify J(-p?,-q?,`i') = p.q^`i';
+	Identify K(-p?,`i') = D.p^-`i';
+	Identify K(-p?,-q?,`i') = p.q^-`i';
+
+	Identify L(-p?,`i') = (D.p)^`i';
+	Identify L(-p?,-q?,`i') = (p.q)^`i';
+	Identify M(-p?,`i') = D.p^(`i');
+	Identify M(-p?,-q?,`i') = p.q^(`i');
+#enddo
+
+Print +s;
+.end
+assert succeeded?
+assert result("test") =~ expr("0")
+*--#] Issue544 :
 *--#[ Issue563 :
 #: SubTermsInSmall 50
 

sources/wildcard.c

@@ -306,6 +306,7 @@ Seven:;
 				while ( t < u ) {
 					*m = *t;
 					subcount = 0;
+					/* Process the first vector of the DOTPRODUCT */
 					for ( si = 0; si < setflag; si += 2 ) {
 						if ( t == temp + setlist[si] ) goto ss2;
 					}
@@ -316,7 +317,17 @@ Seven:;
 								*m = s[3]; dirty = 1; break;
 							}
 							if ( *s == VECTOMIN ) {
-								*m = s[3]; dirty = 1; sgn += t[2]; break;
+								*m = s[3];
+								dirty = 1;
+								if ( ( ABS(t[2]) - 2*MAXPOWER ) < 0 ) {
+									/* The power is a number */
+									sgn += t[2];
+								}
+								else {
+									/* The power is a wildcard. Put a -, resolve later. */
+									sgn++;
+								}
+								break;
 							}
 							if ( *s == VECTOSUB ) {
 								*m = s[3]; dirty = 1; subcount = 1; break;
@@ -327,6 +338,7 @@ Seven:;
 ss2:
 					*++m = *++t;
 					s = subs;
+					/* Process the second vector of the DOTPRODUCT */
 					for ( si = 0; si < setflag; si += 2 ) {
 						if ( t == temp + setlist[si] ) goto ss3;
 					}
@@ -336,7 +348,17 @@ Seven:;
 								*m = s[3]; dirty = 1; break;
 							}
 							if ( *s == VECTOMIN ) {
-								*m = s[3]; dirty = 1; sgn += t[1]; break;
+								*m = s[3];
+								dirty = 1;
+								if ( ( ABS(t[1]) - 2*MAXPOWER ) < 0 ) {
+									/* The power is a number */
+									sgn += t[1];
+								}
+								else {
+									/* The power is a wildcard. Put a -, resolve later. */
+									sgn++;
+								}
+								break;
 							}
 							if ( *s == VECTOSUB ) {
 								*m = s[3]; dirty = 1; subcount += 2; break;
@@ -345,12 +367,18 @@ Seven:;
 						s += s[1];
 					}
 ss3:				*++m = *++t;
+					/* Process the power */
 					if ( ( ABS(*t) - 2*MAXPOWER ) < 0 ) goto RegPow;
 					s = subs;
 					for ( j = 0; j < i; j++ ) {
 						if ( ( ABS(*t) - 2*MAXPOWER ) == s[2] ) {
 							if ( *s == SYMTONUM ) {
 								*m = s[3];
+								/* Since the power is a wildcard, sgn is 0,1,2 depending whether
+									there were 0,1,2 VECTOMIN in the DOTPRODUCT. Multiply by the
+									power, which is positive currently. */
+								sgn *= *m;
+								/* Now flip the sign of the power, if the wildcard came with a - */
 								if ( *t < 0 ) *m = -*m;
 								dirty = 1;
 								break;