[GiNaC-devel] Bug(?) in reposition_dummy_indices: test case and patch

[Chris Dams]

Dear Alexei,

On Tue, 29 Aug 2006, Sheplyakov Alexei wrote:

> This simple program
>
> [...]
> 
> fails (both with GiNaC 1.4 CVS and 1.3.x). I believe that the reason 
> is bug in indexed.cpp:reposition_dummy_indices() and propose attached
> patch to fix it. Note that patch *seems* to be correct, but IMHO it
> is somewhat ugly and probably inefficient. Could anyone suggest a better
> solution?

What if we simply don't do this kind of toggling of the variance in the
case that both indices of the dummy pair belong to the same indexed object
and the indexed object has a symmetry in which the dummy pair is involved?
Seems simpler to me.

Best wishes,
Chris