* mul::expand(): Considerable speedup through caching in nested loop.

[ginac.git] / ginac / mul.cpp

diff --git a/ginac/mul.cpp b/ginac/mul.cpp
index 51668803a88371322901cf9c4a35c2f6011d4295..c7fb32a1527123a02b9fd82ffc677672af49c870 100644 (file)
--- a/ginac/mul.cpp
+++ b/ginac/mul.cpp
@@ -141,7 +141,7 @@ void mul::print(const print_context & c, unsigned level) const
                while (it != itend) {
 
                        // If the first argument is a negative integer power, it gets printed as "1.0/<expr>"
-                       if (it == seq.begin() && ex_to<numeric>(it->coeff).is_integer() && it->coeff.compare(_num0) < 0) {
+                       if (it == seq.begin() && ex_to<numeric>(it->coeff).is_integer() && it->coeff.info(info_flags::negative)) {
                                if (is_a<print_csrc_cl_N>(c))
                                        c.s << "recip(";
                                else
@@ -149,7 +149,7 @@ void mul::print(const print_context & c, unsigned level) const
                        }
 
                        // If the exponent is 1 or -1, it is left out
-                       if (it->coeff.compare(_ex1) == 0 || it->coeff.compare(_num_1) == 0)
+                       if (it->coeff.is_equal(_ex1) || it->coeff.is_equal(_ex_1))
                                it->rest.print(c, precedence());
                        else {
                                // Outer parens around ex needed for broken gcc-2.95 parser:
@@ -159,7 +159,7 @@ void mul::print(const print_context & c, unsigned level) const
                        // Separator is "/" for negative integer powers, "*" otherwise
                        ++it;
                        if (it != itend) {
-                               if (ex_to<numeric>(it->coeff).is_integer() && it->coeff.compare(_num0) < 0)
+                               if (ex_to<numeric>(it->coeff).is_integer() && it->coeff.info(info_flags::negative))
                                        c.s << "/";
                                else
                                        c.s << "*";
@@ -693,9 +693,10 @@ ex mul::expand(unsigned options) const
                                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));
-                                       }
+                                       // cache the first operand (for efficiency):
+                                       const ex op1 = add1.op(i1);
+                                       for (int i2=0; i2<n2; ++i2)
+                                               distrseq.push_back(op1 * add2.op(i2));
                                }
                                last_expanded = (new add(distrseq))->
                                                 setflag(status_flags::dynallocated | (options == 0 ? status_flags::expanded : 0));