* Avoid bad choice of main variable in heuristic gcd [Alexei Sheplyakov].

[ginac.git] / ginac / symmetry.cpp

diff --git a/ginac/symmetry.cpp b/ginac/symmetry.cpp
index 96225e7416437068816a422f51cc5de6a6116513..e48e269851e0846442bbbc1975928348e8d24271 100644 (file)
--- a/ginac/symmetry.cpp
+++ b/ginac/symmetry.cpp
@@ -142,11 +142,69 @@ int symmetry::compare_same_type(const basic & other) const
 {
        GINAC_ASSERT(is_a<symmetry>(other));
 
-       // All symmetry trees are equal. They are not supposed to appear in
-       // ordinary expressions anyway...
+       // For archiving purposes we need to have an ordering of symmetries.
+       const symmetry &othersymm = ex_to<symmetry>(other);
+
+       // Compare type.
+       if (type > othersymm.type)
+               return 1;
+       if (type < othersymm.type)
+               return -1;
+
+       // Compare the index set.
+       size_t this_size = indices.size();
+       size_t that_size = othersymm.indices.size();
+       if (this_size > that_size)
+               return 1;
+       if (this_size < that_size)
+               return -1;
+       typedef std::set<unsigned>::iterator set_it;
+       set_it end = indices.end();
+       for (set_it i=indices.begin(),j=othersymm.indices.begin(); i!=end; ++i,++j) {
+               if(*i < *j)
+                       return 1;
+               if(*i > *j)
+                       return -1;
+       }
+
+       // Compare the children.
+       if (children.size() > othersymm.children.size())
+               return 1;
+       if (children.size() < othersymm.children.size())
+               return -1;
+       for (size_t i=0; i<children.size(); ++i) {
+               int cmpval = ex_to<symmetry>(children[i])
+                       .compare_same_type(ex_to<symmetry>(othersymm.children[i]));
+               if (cmpval)
+                       return cmpval;
+       }
+
        return 0;
 }
 
+unsigned symmetry::calchash() const
+{
+       unsigned v = golden_ratio_hash((p_int)tinfo());
+
+       if (type == none) {
+               v = rotate_left(v);
+               v ^= *(indices.begin());
+       } else {
+               for (exvector::const_iterator i=children.begin(); i!=children.end(); ++i)
+               {
+                       v = rotate_left(v);
+                       v ^= i->gethash();
+               }
+       }
+
+       if (flags & status_flags::evaluated) {
+               setflag(status_flags::hash_calculated);
+               hashvalue = v;
+       }
+
+       return v;
+}
+
 void symmetry::do_print(const print_context & c, unsigned level) const
 {
        if (children.empty()) {
@@ -208,6 +266,18 @@ void symmetry::do_print_tree(const print_tree & c, unsigned level) const
 // non-virtual functions in this class
 //////////
 
+bool symmetry::has_cyclic() const
+{
+       if (type == cyclic)
+               return true;
+
+       for (exvector::const_iterator i=children.begin(); i!=children.end(); ++i)
+               if (ex_to<symmetry>(*i).has_cyclic())
+                       return true;
+
+       return false;
+}
+
 symmetry &symmetry::add(const symmetry &c)
 {
        // All children must have the same number of indices