[GiNaC-list] bug in series expansion of powers

[Sheplyakov Alexei]

Hello!

This simple program

#include <iostream>
#include <ginac/ginac.h>
using namespace std;
using namespace GiNaC;

int main(int argc, char** argv)
{
	symbol x("x");
	symbol a("a");
	symbol b("b");
	ex test = pow(x+a,b);
	cout << test << " = " << test.series(x,3) << endl;
	return 0;
}

gives

(x+a)^b = 1+Order(x^3)

instead of 

(x+a)^b = (a^b)+(a^b*b*a^(-1))*x+(1/2*a^b*b^2*a^(-2)-1/2*a^b*b*a^(-2))*x^2+Order(x^3)

Attached patch fix this bug.

-------------- next part --------------
diff -Nru GiNaC/ginac/pseries.cpp GiNaC-hacked/ginac/pseries.cpp
--- GiNaC/ginac/pseries.cpp	2004-08-09 18:32:09.000000000 +0400
+++ GiNaC-hacked/ginac/pseries.cpp	2004-10-01 10:21:00.000000000 +0400
@@ -955,10 +955,16 @@
 	if (!must_expand_basis && !exponent.info(info_flags::negint) && !is_a<add>(basis))
 		return basic::series(r, order, options);
 
+	if (!must_expand_basis && !exponent.info(info_flags::negint) && !is_a<numeric>(exponent))
+		return basic::series(r, order, options);
+
 	// Is the expression of type 0^something?
 	if (!must_expand_basis && !basis.subs(r, subs_options::no_pattern).is_zero() && !is_a<add>(basis))
 		return basic::series(r, order, options);
 
+	if (!must_expand_basis && !basis.subs(r, subs_options::no_pattern).is_zero() && !is_a<numeric>(exponent))
+		return basic::series(r, order, options);
+
 	// Singularity encountered, is the basis equal to (var - point)?
 	if (basis.is_equal(r.lhs() - r.rhs())) {
 		epvector new_seq;