Converting terms into primitive polynomials optimized [A.Sheplyakov]
[ginac.git] / ginac / mul.cpp
index b4ef8972920d96b6f5b5043ba5ed404d8d561522..9ed27c6c4bf3f4c7435674de9138bb4aa16d76fc 100644 (file)
@@ -34,6 +34,7 @@
 #include "lst.h"
 #include "archive.h"
 #include "utils.h"
+#include "compiler.h"
 
 namespace GiNaC {
 
@@ -422,7 +423,7 @@ ex mul::eval(int level) const
                return *this;
        }
        
-       int seq_size = seq.size();
+       size_t seq_size = seq.size();
        if (overall_coeff.is_zero()) {
                // *(...,x;0) -> 0
                return _ex0;
@@ -448,14 +449,18 @@ ex mul::eval(int level) const
                                ex_to<numeric>(addref.overall_coeff).
                                mul_dyn(ex_to<numeric>(overall_coeff)))
                       )->setflag(status_flags::dynallocated | status_flags::evaluated);
-       } else if (seq_size >= 2) {
+       } else if ((seq_size >= 2) && (! (flags & status_flags::expanded))) {
                // Strip the content and the unit part from each term. Thus
                // things like (-x+a)*(3*x-3*a) automagically turn into - 3*(x-a)2
 
                epvector::const_iterator last = seq.end();
                epvector::const_iterator i = seq.begin();
+               epvector::const_iterator j = seq.begin();
+               std::auto_ptr<epvector> s(new epvector);
+               numeric oc = *_num1_p;
+               bool something_changed = false;
                while (i!=last) {
-                       if (! (is_a<add>(i->rest) && i->coeff.is_equal(_ex1))) {
+                       if (likely(! (is_a<add>(i->rest) && i->coeff.is_equal(_ex1)))) {
                                // power::eval has such a rule, no need to handle powers here
                                ++i;
                                continue;
@@ -472,32 +477,47 @@ ex mul::eval(int level) const
                        // very unlucky event it can even loop forever). Hopefully the main
                        // variable will be the same for all terms in *this
                        const bool unit_normal = lead_coeff.is_pos_integer();
-                       if ((c == *_num1_p) && ((! canonicalizable) || unit_normal)) {
+                       if (likely((c == *_num1_p) && ((! canonicalizable) || unit_normal))) {
                                ++i;
                                continue;
                        }
 
-                       std::auto_ptr<epvector> s(new epvector);
-                       s->reserve(seq.size());
+                       if (! something_changed) {
+                               s->reserve(seq_size);
+                               something_changed = true;
+                       }
 
-                       epvector::const_iterator j=seq.begin();
-                       while (j!=i) {
+                       while ((j!=i) && (j!=last)) {
                                s->push_back(*j);
                                ++j;
                        }
 
-                       if (! unit_normal) {
+                       if (! unit_normal)
                                c = c.mul(*_num_1_p);
-                       }
-                       const ex primitive = (i->rest)/c;
-                       s->push_back(expair(primitive, _ex1));
-                       ++j;
 
+                       oc = oc.mul(c);
+
+                       // divide add by the number in place to save at least 2 .eval() calls
+                       const add& addref = ex_to<add>(i->rest);
+                       add* primitive = new add(addref);
+                       primitive->setflag(status_flags::dynallocated);
+                       primitive->clearflag(status_flags::hash_calculated);
+                       primitive->overall_coeff = ex_to<numeric>(primitive->overall_coeff).div_dyn(c);
+                       for (epvector::iterator ai = primitive->seq.begin();
+                                       ai != primitive->seq.end(); ++ai)
+                               ai->coeff = ex_to<numeric>(ai->coeff).div_dyn(c);
+                       
+                       s->push_back(expair(*primitive, _ex1));
+
+                       ++i;
+                       ++j;
+               }
+               if (something_changed) {
                        while (j!=last) {
                                s->push_back(*j);
                                ++j;
                        }
-                       return (new mul(s, ex_to<numeric>(overall_coeff).mul_dyn(c))
+                       return (new mul(s, ex_to<numeric>(overall_coeff).mul_dyn(oc))
                               )->setflag(status_flags::dynallocated);
                }
        }