[GiNaC-list] Simplifying indexed expressions not working on multi-indices scalar_product

Chris Dams Chris.Dams at mi.infn.it
Thu Jul 27 13:08:59 CEST 2006

Dear Alejandro,

On Wed, 26 Jul 2006, Alejandro Limache wrote:

> According to section 4.14.5 "Simplifying indexed expressions" of the 
> tutorial,
> if I set:
>          scalar_products sp;
>          sp.add(A, B, 0);
> then:
>         A~mu~nu*B.mu.nu
> should be replaced by zero when using .simplify_indexed(sp).
> This is not working. See my simple code below.

Ah yes, I see. Actually, I removed this possibility from the library some
time ago. See:
http://www.ginac.de/pipermail/ginac-devel/2005-December/000878.html Since
I thought that nobody would be using this feature, I, in the end, did what
I said in the "Note:" and now GiNaC does not try anymore to apply
scalar_products in case that the indexed objects have more than one index.  
Of course, the tutorial should also be made consistent with this, so I
will do that. On the other hand, you might also try to convince me that we
really do need this kind of contraction...

Thanks for pointing this out, anyway.

Best wishes,

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