From: Jens Vollinga <vollinga@thep.physik.uni-mainz.de>
Date: Mon, 15 Oct 2007 23:40:30 +0000 (+0000)
Subject: - Apparently, in ~ 30% of calls to mul::expand the expression is monomial.
X-Git-Tag: release_1-5-0~133
X-Git-Url: https://www.ginac.de/ginac.git//ginac.git?p=ginac.git;a=commitdiff_plain;h=da6a61ba2586263e46ade4b67dca121506c2bff9;hp=7d05f39c095dc51cc4526b17a5ab3280f8924219

- Apparently, in ~ 30% of calls to mul::expand the expression is monomial.
Expanding monomials should be done as fast as possible [Sheplyakov].
---

diff --git a/ginac/mul.cpp b/ginac/mul.cpp
index db8b9f14..298715b3 100644
--- a/ginac/mul.cpp
+++ b/ginac/mul.cpp
@@ -34,6 +34,7 @@
 #include "lst.h"
 #include "archive.h"
 #include "utils.h"
+#include "symbol.h"
 #include "compiler.h"
 
 namespace GiNaC {
@@ -992,6 +993,15 @@ bool mul::can_be_further_expanded(const ex & e)
 
 ex mul::expand(unsigned options) const
 {
+	{
+  	// trivial case: expanding the monomial (~ 30% of all calls)
+		epvector::const_iterator i = seq.begin(), seq_end = seq.end();
+		while ((i != seq.end()) &&  is_a<symbol>(i->rest) && i->coeff.info(info_flags::integer))
+			++i;
+		if (i == seq_end)
+			return (new mul(*this))->setflag(status_flags::dynallocated | status_flags::expanded);
+	}
+
 	const bool skip_idx_rename = ! info(info_flags::has_indices);
 	// First, expand the children
 	std::auto_ptr<epvector> expanded_seqp = expandchildren(options);
diff --git a/ginac/power.cpp b/ginac/power.cpp
index 10de528d..1b28b509 100644
--- a/ginac/power.cpp
+++ b/ginac/power.cpp
@@ -772,6 +772,9 @@ tinfo_t power::return_type_tinfo() const
 
 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))
 		return *this;