[GiNaC-devel] [PATCH] fix incorrect result: degree(c*x^(-1), x^(-1)) gives zero

[Alexei Sheplyakov]

Hello!

degree(c*x^(-1), x^(-1)) (in ginsh notation) gives zero instead of
expected 1. On the other hand, degree(x^(-1), x^(-1))
and coeff(c*x^(-1), x^(-1)) work fine.

This patch makes degree (and ldegree) work correct with such arguments.

---
 ginac/mul.cpp |   12 ++++++++++--
 1 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/ginac/mul.cpp b/ginac/mul.cpp
index dd96a70..9bbcd61 100644
--- a/ginac/mul.cpp
+++ b/ginac/mul.cpp
@@ -315,7 +315,11 @@ int mul::degree(const ex & s) const
 	epvector::const_iterator i = seq.begin(), end = seq.end();
 	while (i != end) {
 		if (ex_to<numeric>(i->coeff).is_integer())
-			deg_sum += i->rest.degree(s) * ex_to<numeric>(i->coeff).to_int();
+			deg_sum += recombine_pair_to_ex(*i).degree(s);
+		else {
+			if (i->rest.has(s))
+				throw std::runtime_error("mul::degree() undefined degree because of non-integer exponent");
+		}
 		++i;
 	}
 	return deg_sum;
@@ -328,7 +332,11 @@ int mul::ldegree(const ex & s) const
 	epvector::const_iterator i = seq.begin(), end = seq.end();
 	while (i != end) {
 		if (ex_to<numeric>(i->coeff).is_integer())
-			deg_sum += i->rest.ldegree(s) * ex_to<numeric>(i->coeff).to_int();
+			deg_sum += recombine_pair_to_ex(*i).ldegree(s);
+		else {
+			if (i->rest.has(s))
+				throw std::runtime_error("mul::ldegree() undefined degree because of non-integer exponent");
+		}
 		++i;
 	}
 	return deg_sum;
-- 
1.4.4.4


Best regards,
 Alexei

-- 
All science is either physics or stamp collecting.

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