From c7299e51d5ecf61b5d85bdfeb9a2db536abf18bb Mon Sep 17 00:00:00 2001
From: Richard Kreckel <kreckel@ginac.de>
Date: Sun, 11 Oct 2009 23:19:21 +0200
Subject: [PATCH] Add mul::info() and add::info() support for numeric
 info_flags.

This way, GiNaC knows that the sum or product of a number of positive
expressions is again a positive expression. [by Vladimir Kisil]
---
 ginac/add.cpp   | 12 ++++++++++++
 ginac/flags.h   |  2 +-
 ginac/mul.cpp   | 12 ++++++++++++
 ginac/power.cpp |  2 ++
 4 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/ginac/add.cpp b/ginac/add.cpp
index 4c857044..5f714fef 100644
--- a/ginac/add.cpp
+++ b/ginac/add.cpp
@@ -224,6 +224,16 @@ bool add::info(unsigned inf) const
 		case info_flags::integer_polynomial:
 		case info_flags::cinteger_polynomial:
 		case info_flags::rational_polynomial:
+		case info_flags::real:
+		case info_flags::rational:
+		case info_flags::integer:
+		case info_flags::crational:
+		case info_flags::cinteger:
+		case info_flags::positive:
+		case info_flags::nonnegative:
+		case info_flags::posint:
+		case info_flags::nonnegint:
+		case info_flags::even:
 		case info_flags::crational_polynomial:
 		case info_flags::rational_function: {
 			epvector::const_iterator i = seq.begin(), end = seq.end();
@@ -232,6 +242,8 @@ bool add::info(unsigned inf) const
 					return false;
 				++i;
 			}
+			if (overall_coeff.is_zero() && (inf == info_flags::positive || inf == info_flags::posint))
+				return true;
 			return overall_coeff.info(inf);
 		}
 		case info_flags::algebraic: {
diff --git a/ginac/flags.h b/ginac/flags.h
index c4593dc4..547cc594 100644
--- a/ginac/flags.h
+++ b/ginac/flags.h
@@ -204,7 +204,7 @@ public:
 class info_flags {
 public:
 	enum {
-		// answered by class numeric and symbols/constants in particular domains
+		// answered by class numeric, add, mul and symbols/constants in particular domains
 		numeric,
 		real,
 		rational,
diff --git a/ginac/mul.cpp b/ginac/mul.cpp
index 35ba88e4..bc38159d 100644
--- a/ginac/mul.cpp
+++ b/ginac/mul.cpp
@@ -278,6 +278,16 @@ bool mul::info(unsigned inf) const
 		case info_flags::integer_polynomial:
 		case info_flags::cinteger_polynomial:
 		case info_flags::rational_polynomial:
+		case info_flags::real:
+		case info_flags::rational:
+		case info_flags::integer:
+		case info_flags::crational:
+		case info_flags::cinteger:
+		case info_flags::positive:
+		case info_flags::nonnegative:
+		case info_flags::posint:
+		case info_flags::nonnegint:
+		case info_flags::even:
 		case info_flags::crational_polynomial:
 		case info_flags::rational_function: {
 			epvector::const_iterator i = seq.begin(), end = seq.end();
@@ -286,6 +296,8 @@ bool mul::info(unsigned inf) const
 					return false;
 				++i;
 			}
+			if (overall_coeff.is_equal(*_num1_p) && inf == info_flags::even)
+				return true;
 			return overall_coeff.info(inf);
 		}
 		case info_flags::algebraic: {
diff --git a/ginac/power.cpp b/ginac/power.cpp
index 999d9b14..7ae0f04d 100644
--- a/ginac/power.cpp
+++ b/ginac/power.cpp
@@ -240,6 +240,8 @@ bool power::info(unsigned inf) const
 			       basis.info(inf);
 		case info_flags::expanded:
 			return (flags & status_flags::expanded);
+		case info_flags::positive:
+			return basis.info(info_flags::positive) && exponent.info(info_flags::real);
 		case info_flags::has_indices: {
 			if (flags & status_flags::has_indices)
 				return true;
-- 
2.44.0