[GiNaC-list] Term ordering and compiling C++ code

[Doug]

This doesn't work.  I may be wrong on the explanation, so someone with more experience please correct me.

On cursory inspection of ex_is_less and the compare functions it references, ex_is_less boils down to a) comparing the expressions hash values.  If they are the same, which is the case that matters, then b) you test pointer values.  But each expression in the expression tree will have its own pointer, or at least it appears to in practice.