polynomial: introduce a helper function to divide polynomial by ring element.

[ginac.git] / ginac / symmetry.cpp

diff --git a/ginac/symmetry.cpp b/ginac/symmetry.cpp
index 96225e7416437068816a422f51cc5de6a6116513..215a48a08d78ae88ea8cee7052490eb2a72f85b3 100644 (file)
--- a/ginac/symmetry.cpp
+++ b/ginac/symmetry.cpp
@@ -3,7 +3,7 @@
  *  Implementation of GiNaC's symmetry definitions. */
 
 /*
- *  GiNaC Copyright (C) 1999-2006 Johannes Gutenberg University Mainz, Germany
+ *  GiNaC Copyright (C) 1999-2008 Johannes Gutenberg University Mainz, Germany
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -23,6 +23,7 @@
 #include <iostream>
 #include <stdexcept>
 #include <functional>
+#include <limits>
 
 #include "symmetry.h"
 #include "lst.h"
@@ -142,11 +143,69 @@ 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 +267,18 @@ 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
@@ -361,7 +432,7 @@ int canonicalize(exvector::iterator v, const symmetry &symm)
 {
        // Less than two elements? Then do nothing
        if (symm.indices.size() < 2)
-               return INT_MAX;
+               return std::numeric_limits<int>::max();
 
        // Canonicalize children first
        bool something_changed = false;
@@ -372,7 +443,7 @@ int canonicalize(exvector::iterator v, const symmetry &symm)
                int child_sign = canonicalize(v, ex_to<symmetry>(*first));
                if (child_sign == 0)
                        return 0;
-               if (child_sign != INT_MAX) {
+               if (child_sign != std::numeric_limits<int>::max()) {
                        something_changed = true;
                        sign *= child_sign;
                }
@@ -399,7 +470,7 @@ int canonicalize(exvector::iterator v, const symmetry &symm)
                default:
                        break;
        }
-       return something_changed ? sign : INT_MAX;
+       return something_changed ? sign : std::numeric_limits<int>::max();
 }