new iterative mul::expand()

diff --git a/ginac/mul.cpp b/ginac/mul.cpp
index ad7aa13e3d5e5568241398f18ab55788241e94ad..97d63f8801ce4ac7f07b3687e0689a9b20ae83c4 100644 (file)
--- a/ginac/mul.cpp
+++ b/ginac/mul.cpp
@@ -652,6 +652,74 @@ bool mul::can_make_flat(const expair & p) const
        return ex_to_numeric(p.coeff).is_equal(_num1());
 }
 
+ex mul::expand(unsigned options) const
+{
+       if (flags & status_flags::expanded)
+               return *this;
+       
+       exvector sub_expanded_seq;
+       intvector positions_of_adds;
+       
+       epvector * expanded_seqp = expandchildren(options);
+       
+       const epvector & expanded_seq = expanded_seqp==0 ? seq : *expanded_seqp;
+       
+       int number_of_adds = 0;
+       epvector non_adds;
+       non_adds.reserve(expanded_seq.size());
+       epvector::const_iterator cit=expanded_seq.begin();
+       epvector::const_iterator last = expanded_seq.end();
+       ex last_expanded=_ex1();
+       while (cit!=last) {
+               if (is_ex_exactly_of_type((*cit).rest,add) &&
+                       ((*cit).coeff.is_equal(_ex1()))) {
+                       ++number_of_adds;
+                       if (is_ex_exactly_of_type(last_expanded,add)) {
+                               // expand adds
+                               add const & add1=ex_to_add(last_expanded);
+                               add const & add2=ex_to_add((*cit).rest);
+                               int n1=add1.nops();
+                               int n2=add2.nops();
+                               exvector distrseq;
+                               distrseq.reserve(n1*n2);
+                               for (int i1=0; i1<n1; ++i1) {
+                                       for (int i2=0; i2<n2; ++i2) {
+                                               distrseq.push_back(add1.op(i1)*add2.op(i2));
+                                       }
+                               }
+                               last_expanded=(new add(distrseq))->setflag(status_flags::dynallocated | status_flags::expanded);
+                       } else {
+                               non_adds.push_back(split_ex_to_pair(last_expanded));
+                               last_expanded=(*cit).rest;
+                       }
+               } else {
+                       non_adds.push_back(*cit);
+               }
+               ++cit;
+       }
+
+       if (is_ex_exactly_of_type(last_expanded,add)) {
+               //ex factors=(new mul(non_adds,overall_coeff))->
+               //             setflag(status_flags::dynallocated | status_flags::expanded);
+               add const & finaladd=ex_to_add(last_expanded);
+               exvector distrseq;
+               int n=finaladd.nops();
+               distrseq.reserve(n);
+               for (int i=0; i<n; ++i) {
+                       //distrseq.push_back(factors*finaladd.op(i));
+                       epvector factors=non_adds;
+                       factors.push_back(split_ex_to_pair(finaladd.op(i)));
+                       distrseq.push_back((new mul(factors,overall_coeff))->setflag(status_flags::dynallocated | status_flags::expanded));
+               }
+               return ((new add(distrseq))->
+                      setflag(status_flags::dynallocated | status_flags::expanded));
+       }
+       non_adds.push_back(split_ex_to_pair(last_expanded));
+       return (new mul(non_adds,overall_coeff))->
+              setflag(status_flags::dynallocated | status_flags::expanded);
+}
+
+/*
 ex mul::expand(unsigned options) const
 {
        if (flags & status_flags::expanded)
@@ -726,7 +794,8 @@ ex mul::expand(unsigned options) const
        return (new add(distrseq))->setflag(status_flags::dynallocated |
                                                                                status_flags::expanded);
 }
-
+*/
+  
 //////////
 // new virtual functions which can be overridden by derived classes
 //////////