From: Jens Vollinga <vollinga@thep.physik.uni-mainz.de>
Date: Mon, 27 Aug 2007 16:46:44 +0000 (+0000)
Subject: Converting terms into primitive polynomials optimized [A.Sheplyakov]
X-Git-Tag: release_1-4-0~7
X-Git-Url: https://www.ginac.de/ginac.git//ginac.git?p=ginac.git;a=commitdiff_plain;h=9e1051ad0a532338a6f995b9f41f17ac5cdc47a6;hp=47923e5885d0e437d6cbe257c25f9bca757ea001

Converting terms into primitive polynomials optimized [A.Sheplyakov]
---

diff --git a/ginac/mul.cpp b/ginac/mul.cpp
index b4ef8972..9ed27c6c 100644
--- a/ginac/mul.cpp
+++ b/ginac/mul.cpp
@@ -34,6 +34,7 @@
 #include "lst.h"
 #include "archive.h"
 #include "utils.h"
+#include "compiler.h"
 
 namespace GiNaC {
 
@@ -422,7 +423,7 @@ ex mul::eval(int level) const
 		return *this;
 	}
 	
-	int seq_size = seq.size();
+	size_t seq_size = seq.size();
 	if (overall_coeff.is_zero()) {
 		// *(...,x;0) -> 0
 		return _ex0;
@@ -448,14 +449,18 @@ ex mul::eval(int level) const
 		                ex_to<numeric>(addref.overall_coeff).
 		                mul_dyn(ex_to<numeric>(overall_coeff)))
 		       )->setflag(status_flags::dynallocated | status_flags::evaluated);
-	} else if (seq_size >= 2) {
+	} else if ((seq_size >= 2) && (! (flags & status_flags::expanded))) {
 		// Strip the content and the unit part from each term. Thus
 		// things like (-x+a)*(3*x-3*a) automagically turn into - 3*(x-a)2
 
 		epvector::const_iterator last = seq.end();
 		epvector::const_iterator i = seq.begin();
+		epvector::const_iterator j = seq.begin();
+		std::auto_ptr<epvector> s(new epvector);
+		numeric oc = *_num1_p;
+		bool something_changed = false;
 		while (i!=last) {
-			if (! (is_a<add>(i->rest) && i->coeff.is_equal(_ex1))) {
+			if (likely(! (is_a<add>(i->rest) && i->coeff.is_equal(_ex1)))) {
 				// power::eval has such a rule, no need to handle powers here
 				++i;
 				continue;
@@ -472,32 +477,47 @@ ex mul::eval(int level) const
 			// very unlucky event it can even loop forever). Hopefully the main
 			// variable will be the same for all terms in *this
 			const bool unit_normal = lead_coeff.is_pos_integer();
-			if ((c == *_num1_p) && ((! canonicalizable) || unit_normal)) {
+			if (likely((c == *_num1_p) && ((! canonicalizable) || unit_normal))) {
 				++i;
 				continue;
 			}
 
-			std::auto_ptr<epvector> s(new epvector);
-			s->reserve(seq.size());
+			if (! something_changed) {
+				s->reserve(seq_size);
+				something_changed = true;
+			}
 
-			epvector::const_iterator j=seq.begin();
-			while (j!=i) {
+			while ((j!=i) && (j!=last)) {
 				s->push_back(*j);
 				++j;
 			}
 
-			if (! unit_normal) {
+			if (! unit_normal)
 				c = c.mul(*_num_1_p);
-			}
-			const ex primitive = (i->rest)/c;
-			s->push_back(expair(primitive, _ex1));
-			++j;
 
+			oc = oc.mul(c);
+
+			// divide add by the number in place to save at least 2 .eval() calls
+			const add& addref = ex_to<add>(i->rest);
+			add* primitive = new add(addref);
+			primitive->setflag(status_flags::dynallocated);
+			primitive->clearflag(status_flags::hash_calculated);
+			primitive->overall_coeff = ex_to<numeric>(primitive->overall_coeff).div_dyn(c);
+			for (epvector::iterator ai = primitive->seq.begin();
+					ai != primitive->seq.end(); ++ai)
+				ai->coeff = ex_to<numeric>(ai->coeff).div_dyn(c);
+			
+			s->push_back(expair(*primitive, _ex1));
+
+			++i;
+			++j;
+		}
+		if (something_changed) {
 			while (j!=last) {
 				s->push_back(*j);
 				++j;
 			}
-			return (new mul(s, ex_to<numeric>(overall_coeff).mul_dyn(c))
+			return (new mul(s, ex_to<numeric>(overall_coeff).mul_dyn(oc))
 			       )->setflag(status_flags::dynallocated);
 		}
 	}
diff --git a/ginac/power.cpp b/ginac/power.cpp
index faaef184..faa0d05c 100644
--- a/ginac/power.cpp
+++ b/ginac/power.cpp
@@ -41,6 +41,7 @@
 #include "archive.h"
 #include "utils.h"
 #include "relational.h"
+#include "compiler.h"
 
 namespace GiNaC {
 
@@ -482,25 +483,29 @@ 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)) {
-			const numeric icont = ebasis.integer_content();
+			numeric icont = ebasis.integer_content();
 			const numeric& lead_coeff = 
 				ex_to<numeric>(ex_to<add>(ebasis).seq.begin()->coeff).div_dyn(icont);
 
 			const bool canonicalizable = lead_coeff.is_integer();
 			const bool unit_normal = lead_coeff.is_pos_integer();
-
-			if (icont != *_num1_p) {
-				return (new mul(power(ebasis/icont, *num_exponent), power(icont, *num_exponent))
-				       )->setflag(status_flags::dynallocated);
-			}
-
-			if (canonicalizable && (! unit_normal)) {
-				if (num_exponent->is_even()) {
-					return power(-ebasis, *num_exponent);
-				} else {
-					return (new mul(power(-ebasis, *num_exponent), *_num_1_p)
-					       )->setflag(status_flags::dynallocated);
-				}
+			if (canonicalizable && (! unit_normal))
+				icont = icont.mul(*_num_1_p);
+			
+			if (canonicalizable && (icont != *_num1_p)) {
+				const add& addref = ex_to<add>(ebasis);
+				add* addp = new add(addref);
+				addp->setflag(status_flags::dynallocated);
+				addp->clearflag(status_flags::hash_calculated);
+				addp->overall_coeff = ex_to<numeric>(addp->overall_coeff).div_dyn(icont);
+				for (epvector::iterator i = addp->seq.begin(); i != addp->seq.end(); ++i)
+					i->coeff = ex_to<numeric>(i->coeff).div_dyn(icont);
+
+				const numeric c = icont.power(*num_exponent);
+				if (likely(c != *_num1_p))
+					return (new mul(power(*addp, *num_exponent), c))->setflag(status_flags::dynallocated);
+				else
+					return power(*addp, *num_exponent);
 			}
 		}