- removed an unused statement in tensor.cpp

[ginac.git] / ginac / expair.h

diff --git a/ginac/expair.h b/ginac/expair.h
index 954442509e40a52cc1f7f370c977368db6e28a79..513dd5c96442b294f1d4a2a755196155a8459334 100644 (file)
--- a/ginac/expair.h
+++ b/ginac/expair.h
@@ -102,15 +102,30 @@ public:
        ex coeff;   ///< second member of pair, must be numeric
 };
 
-/** Function objects for insertion into third argument of STL's sort() etc. */
+/** Function object for insertion into third argument of STL's sort() etc. */
 struct expair_is_less : public std::binary_function<expair, expair, bool> {
        bool operator()(const expair &lh, const expair &rh) const { return lh.is_less(rh); }
 };
 
+/** Function object not caring about the numerical coefficients for insertion
+ *  into third argument of STL's sort().  Note that this does not define a
+ *  strict weak ordering since for any symbol x we have neither 3*x<2*x or
+ *  2*x<3*x.  Handle with care! */
+struct expair_rest_is_less : public std::binary_function<expair, expair, bool> {
+       bool operator()(const expair &lh, const expair &rh) const { return (lh.rest.compare(rh.rest)<0); }
+};
+
 struct expair_swap : public std::binary_function<expair, expair, void> {
        void operator()(expair &lh, expair &rh) const { lh.swap(rh); }
 };
 
+inline void swap(expair & e1, expair & e2)
+{ e1.swap(e2); }
+
+// This makes STL algorithms use the more efficient swap operation for ex objects
+inline void iter_swap(std::vector<expair>::iterator i1, std::vector<expair>::iterator i2)
+{ i1->swap(*i2); }
+
 } // namespace GiNaC
 
 #endif // ndef __GINAC_EXPAIR_H__