X-Git-Url: https://www.ginac.de/ginac.git//ginac.git?p=ginac.git;a=blobdiff_plain;f=ginac%2Fpower.cpp;h=ca7fea549f43a9c316b67dd503a761be3eeb4024;hp=1b28b509ac4bd35ef4bbcf7777e40069bcf056f2;hb=09988aee53a2bfef87fc887a434b4c78d6326c47;hpb=da6a61ba2586263e46ade4b67dca121506c2bff9

diff --git a/ginac/power.cpp b/ginac/power.cpp
index 1b28b509..ca7fea54 100644
--- a/ginac/power.cpp
+++ b/ginac/power.cpp
@@ -3,7 +3,7 @@
  *  Implementation of GiNaC's symbolic exponentiation (basis^exponent). */
 
 /*
- *  GiNaC Copyright (C) 1999-2007 Johannes Gutenberg University Mainz, Germany
+ *  GiNaC Copyright (C) 1999-2008 Johannes Gutenberg University Mainz, Germany
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -506,8 +506,8 @@ ex power::eval(int level) const
 		// (2*x + 6*y)^(-4) -> 1/16*(x + 3*y)^(-4)
 		if (num_exponent->is_integer() && is_exactly_a<add>(ebasis)) {
 			numeric icont = ebasis.integer_content();
-			const numeric& lead_coeff = 
-				ex_to<numeric>(ex_to<add>(ebasis).seq.begin()->coeff).div_dyn(icont);
+			const numeric lead_coeff = 
+				ex_to<numeric>(ex_to<add>(ebasis).seq.begin()->coeff).div(icont);
 
 			const bool canonicalizable = lead_coeff.is_integer();
 			const bool unit_normal = lead_coeff.is_pos_integer();
@@ -635,7 +635,7 @@ bool power::has(const ex & other, unsigned options) const
 }
 
 // from mul.cpp
-extern bool tryfactsubs(const ex &, const ex &, int &, lst &);
+extern bool tryfactsubs(const ex &, const ex &, int &, exmap&);
 
 ex power::subs(const exmap & m, unsigned options) const
 {	
@@ -651,9 +651,13 @@ ex power::subs(const exmap & m, unsigned options) const
 
 	for (exmap::const_iterator it = m.begin(); it != m.end(); ++it) {
 		int nummatches = std::numeric_limits<int>::max();
-		lst repls;
-		if (tryfactsubs(*this, it->first, nummatches, repls))
-			return (ex_to<basic>((*this) * power(it->second.subs(ex(repls), subs_options::no_pattern) / it->first.subs(ex(repls), subs_options::no_pattern), nummatches))).subs_one_level(m, options);
+		exmap repls;
+		if (tryfactsubs(*this, it->first, nummatches, repls)) {
+			ex anum = it->second.subs(repls, subs_options::no_pattern);
+			ex aden = it->first.subs(repls, subs_options::no_pattern);
+			ex result = (*this)*power(anum/aden, nummatches);
+			return (ex_to<basic>(result)).subs_one_level(m, options);
+		}
 	}
 
 	return subs_one_level(m, options);
@@ -765,19 +769,19 @@ unsigned power::return_type() const
 	return basis.return_type();
 }
 
-tinfo_t power::return_type_tinfo() const
+return_type_t power::return_type_tinfo() const
 {
 	return basis.return_type_tinfo();
 }
 
 ex power::expand(unsigned options) const
 {
-	if (is_a<symbol>(basis) && exponent.info(info_flags::integer))
-		return (new power(*this))->setflag(status_flags::dynallocated | status_flags::expanded);
-
-	if (options == 0 && (flags & status_flags::expanded))
+	if (is_a<symbol>(basis) && exponent.info(info_flags::integer)) {
+		// A special case worth optimizing.
+		setflag(status_flags::expanded);
 		return *this;
-	
+	}
+
 	const ex expanded_basis = basis.expand(options);
 	const ex expanded_exponent = exponent.expand(options);
 	
@@ -864,7 +868,6 @@ ex power::expand_add(const add & a, int n, unsigned options) const
 	intvector k(m-1);
 	intvector k_cum(m-1); // k_cum[l]:=sum(i=0,l,k[l]);
 	intvector upper_limit(m-1);
-	int l;
 
 	for (size_t l=0; l<m-1; ++l) {
 		k[l] = 0;
@@ -875,7 +878,7 @@ ex power::expand_add(const add & a, int n, unsigned options) const
 	while (true) {
 		exvector term;
 		term.reserve(m+1);
-		for (l=0; l<m-1; ++l) {
+		for (std::size_t l = 0; l < m - 1; ++l) {
 			const ex & b = a.op(l);
 			GINAC_ASSERT(!is_exactly_a<add>(b));
 			GINAC_ASSERT(!is_exactly_a<power>(b) ||
@@ -890,7 +893,7 @@ ex power::expand_add(const add & a, int n, unsigned options) const
 				term.push_back(power(b,k[l]));
 		}
 
-		const ex & b = a.op(l);
+		const ex & b = a.op(m - 1);
 		GINAC_ASSERT(!is_exactly_a<add>(b));
 		GINAC_ASSERT(!is_exactly_a<power>(b) ||
 		             !is_exactly_a<numeric>(ex_to<power>(b).exponent) ||
@@ -904,7 +907,7 @@ ex power::expand_add(const add & a, int n, unsigned options) const
 			term.push_back(power(b,n-k_cum[m-2]));
 
 		numeric f = binomial(numeric(n),numeric(k[0]));
-		for (l=1; l<m-1; ++l)
+		for (std::size_t l = 1; l < m - 1; ++l)
 			f *= binomial(numeric(n-k_cum[l-1]),numeric(k[l]));
 
 		term.push_back(f);
@@ -912,12 +915,19 @@ ex power::expand_add(const add & a, int n, unsigned options) const
 		result.push_back(ex((new mul(term))->setflag(status_flags::dynallocated)).expand(options));
 
 		// increment k[]
-		l = m-2;
-		while ((l>=0) && ((++k[l])>upper_limit[l])) {
+		bool done = false;
+		std::size_t l = m - 2;
+		while ((++k[l]) > upper_limit[l]) {
 			k[l] = 0;
-			--l;
+			if (l != 0)
+				--l;
+			else {
+				done = true;
+				break;
+			}
 		}
-		if (l<0) break;
+		if (done)
+			break;
 
 		// recalc k_cum[] and upper_limit[]
 		k_cum[l] = (l==0 ? k[0] : k_cum[l-1]+k[l]);
@@ -1010,8 +1020,13 @@ ex power::expand_mul(const mul & m, const numeric & n, unsigned options, bool fr
 		return _ex1;
 	}
 
+	// do not bother to rename indices if there are no any.
+	if ((!(options & expand_options::expand_rename_idx)) 
+			&& m.info(info_flags::has_indices))
+		options |= expand_options::expand_rename_idx;
 	// Leave it to multiplication since dummy indices have to be renamed
-	if (get_all_dummy_indices(m).size() > 0 && n.is_positive()) {
+	if ((options & expand_options::expand_rename_idx) &&
+		(get_all_dummy_indices(m).size() > 0) && n.is_positive()) {
 		ex result = m;
 		exvector va = get_all_dummy_indices(m);
 		sort(va.begin(), va.end(), ex_is_less());