From: Richard Kreckel <kreckel@ginac.de>
Date: Sat, 7 Nov 2015 00:50:00 +0000 (+0100)
Subject: Add trivial shortcuts in expair plumbing of class add.
X-Git-Tag: ginac_1-6-6~8
X-Git-Url: https://www.ginac.de/ginac.git//ginac.git?p=ginac.git;a=commitdiff_plain;h=bcd95dd63ac2499ee50a416c56ce200cd63521a8

Add trivial shortcuts in expair plumbing of class add.

These little shortcuts in add::split_ex_to_pair(ex) and in
add::combine_ex_with_coeff_to_pair(ex, ex) avoid the creation of
new ex objects. These pieces of code are executed so often that this
patch speeds up GiNaC by 5-10%, depending on test.
---

diff --git a/ginac/add.cpp b/ginac/add.cpp
index d66133eb..ccd49240 100644
--- a/ginac/add.cpp
+++ b/ginac/add.cpp
@@ -564,6 +564,8 @@ expair add::split_ex_to_pair(const ex & e) const
 	if (is_exactly_a<mul>(e)) {
 		const mul &mulref(ex_to<mul>(e));
 		const ex &numfactor = mulref.overall_coeff;
+		if (numfactor.is_equal(_ex1))
+			return expair(e, _ex1);
 		mul *mulcopyp = new mul(mulref);
 		mulcopyp->overall_coeff = _ex1;
 		mulcopyp->clearflag(status_flags::evaluated);
@@ -581,6 +583,8 @@ expair add::combine_ex_with_coeff_to_pair(const ex & e,
 	if (is_exactly_a<mul>(e)) {
 		const mul &mulref(ex_to<mul>(e));
 		const ex &numfactor = mulref.overall_coeff;
+		if (numfactor.is_equal(_ex1))
+			return expair(e, c);
 		mul *mulcopyp = new mul(mulref);
 		mulcopyp->overall_coeff = _ex1;
 		mulcopyp->clearflag(status_flags::evaluated);
@@ -588,13 +592,13 @@ expair add::combine_ex_with_coeff_to_pair(const ex & e,
 		mulcopyp->setflag(status_flags::dynallocated);
 		if (c.is_equal(_ex1))
 			return expair(*mulcopyp, numfactor);
-		else if (numfactor.is_equal(_ex1))
-			return expair(*mulcopyp, c);
 		else
 			return expair(*mulcopyp, ex_to<numeric>(numfactor).mul_dyn(ex_to<numeric>(c)));
 	} else if (is_exactly_a<numeric>(e)) {
 		if (c.is_equal(_ex1))
 			return expair(e, _ex1);
+		if (e.is_equal(_ex1))
+			return expair(c, _ex1);
 		return expair(ex_to<numeric>(e).mul_dyn(ex_to<numeric>(c)), _ex1);
 	}
 	return expair(e, c);