From: Christian Bauer <Christian.Bauer@uni-mainz.de>
Date: Mon, 2 Aug 2004 21:44:44 +0000 (+0000)
Subject: synced to HEAD (power::get_free_indices()) [Alexei Sheplyakov]
X-Git-Tag: release_1-2-2~4
X-Git-Url: https://www.ginac.de/ginac.git//ginac.git?a=commitdiff_plain;h=8581b6818314e3eba844e8e065677a46f6882ca1;p=ginac.git

synced to HEAD (power::get_free_indices()) [Alexei Sheplyakov]
---

diff --git a/check/exam_indexed.cpp b/check/exam_indexed.cpp
index 3d9b307d..e20b5643 100644
--- a/check/exam_indexed.cpp
+++ b/check/exam_indexed.cpp
@@ -375,6 +375,15 @@ static unsigned dummy_check()
 	e = indexed(p, mu.toggle_variance(), mu) - indexed(p, nu, nu.toggle_variance());
 	result += check_equal_simplify(e, 0);
 
+	// GiNaC 1.2.1 had a bug here because p.i*p.i -> (p.i)^2
+	e = indexed(p, i) * indexed(p, i) * indexed(p, j) + indexed(p, j);
+	ex fi = exprseq(e.get_free_indices());
+	if (!fi.is_equal(exprseq(j))) {
+		clog << "get_free_indices(" << e << ") erroneously returned "
+		     << fi << " instead of (.j)" << endl;
+		++result;
+	}
+
 	return result;
 }
 
diff --git a/ginac/indexed.cpp b/ginac/indexed.cpp
index d1d5f728..ad17a497 100644
--- a/ginac/indexed.cpp
+++ b/ginac/indexed.cpp
@@ -499,10 +499,27 @@ exvector ncmul::get_free_indices() const
 	return free_indices;
 }
 
+struct is_summation_idx : public std::unary_function<ex, bool> {
+	bool operator()(const ex & e)
+	{
+		return is_dummy_pair(e, e);
+	}
+};
+
 exvector power::get_free_indices() const
 {
-	// Return free indices of basis
-	return basis.get_free_indices();
+	// Get free indices of basis
+	exvector basis_indices = basis.get_free_indices();
+
+	if (exponent.info(info_flags::even)) {
+		// If the exponent is an even number, then any "free" index that
+		// forms a dummy pair with itself is actually a summation index
+		exvector really_free;
+		std::remove_copy_if(basis_indices.begin(), basis_indices.end(),
+		                    std::back_inserter(really_free), is_summation_idx());
+		return really_free;
+	} else
+		return basis_indices;
 }
 
 /** Rename dummy indices in an expression.