Add trivial shortcuts in expair plumbing of class add.

These little shortcuts in add::split_ex_to_pair(ex) and in
add::combine_ex_with_coeff_to_pair(ex, ex) avoid the creation of
new ex objects. These pieces of code are executed so often that this
patch speeds up GiNaC by 5-10%, depending on test.

diff --git a/ginac/add.cpp b/ginac/add.cpp
index fd83de1134876f448835f9e48722f990c04402a5..a32ae8036a4c29f17591d69be30b90afdf38e80c 100644 (file)
--- a/ginac/add.cpp
+++ b/ginac/add.cpp
@@ -538,6 +538,8 @@ expair add::split_ex_to_pair(const ex & e) const
        if (is_exactly_a<mul>(e)) {
                const mul &mulref(ex_to<mul>(e));
                const ex &numfactor = mulref.overall_coeff;
        if (is_exactly_a<mul>(e)) {
                const mul &mulref(ex_to<mul>(e));
                const ex &numfactor = mulref.overall_coeff;

+               if (numfactor.is_equal(_ex1))
+                       return expair(e, _ex1);

                mul *mulcopyp = new mul(mulref);
                mulcopyp->overall_coeff = _ex1;
                mulcopyp->clearflag(status_flags::evaluated);
                mul *mulcopyp = new mul(mulref);
                mulcopyp->overall_coeff = _ex1;
                mulcopyp->clearflag(status_flags::evaluated);


@@ -555,6 +557,8 @@ expair add::combine_ex_with_coeff_to_pair(const ex & e,
        if (is_exactly_a<mul>(e)) {
                const mul &mulref(ex_to<mul>(e));
                const ex &numfactor = mulref.overall_coeff;
        if (is_exactly_a<mul>(e)) {
                const mul &mulref(ex_to<mul>(e));
                const ex &numfactor = mulref.overall_coeff;

+               if (numfactor.is_equal(_ex1))
+                       return expair(e, c);

                mul *mulcopyp = new mul(mulref);
                mulcopyp->overall_coeff = _ex1;
                mulcopyp->clearflag(status_flags::evaluated);
                mul *mulcopyp = new mul(mulref);
                mulcopyp->overall_coeff = _ex1;
                mulcopyp->clearflag(status_flags::evaluated);


@@ -562,13 +566,13 @@ expair add::combine_ex_with_coeff_to_pair(const ex & e,
                mulcopyp->setflag(status_flags::dynallocated);
                if (c.is_equal(_ex1))
                        return expair(*mulcopyp, numfactor);
                mulcopyp->setflag(status_flags::dynallocated);
                if (c.is_equal(_ex1))
                        return expair(*mulcopyp, numfactor);

-               else if (numfactor.is_equal(_ex1))
-                       return expair(*mulcopyp, c);

                else
                        return expair(*mulcopyp, ex_to<numeric>(numfactor).mul_dyn(ex_to<numeric>(c)));
        } else if (is_exactly_a<numeric>(e)) {
                if (c.is_equal(_ex1))
                        return expair(e, _ex1);
                else
                        return expair(*mulcopyp, ex_to<numeric>(numfactor).mul_dyn(ex_to<numeric>(c)));
        } else if (is_exactly_a<numeric>(e)) {
                if (c.is_equal(_ex1))
                        return expair(e, _ex1);

+               if (e.is_equal(_ex1))
+                       return expair(c, _ex1);

                return expair(ex_to<numeric>(e).mul_dyn(ex_to<numeric>(c)), _ex1);
        }
        return expair(e, c);
                return expair(ex_to<numeric>(e).mul_dyn(ex_to<numeric>(c)), _ex1);
        }
        return expair(e, c);