From kreckel at ginac.de  Wed Sep  6 00:11:37 2006
From: kreckel at ginac.de (Richard B. Kreckel)
Date: Wed, 06 Sep 2006 00:11:37 +0200
Subject: AW: [GiNaC-devel] AsyForGiNaC - an output
	extension	producingAsymptote files
In-Reply-To: <0ML29c-1GE9sU2DEM-0002QX@mrelayeu.kundenserver.de>
References: <0ML29c-1GE9sU2DEM-0002QX@mrelayeu.kundenserver.de>
Message-ID: <44FDF619.8030904@ginac.de>

Daniel Seidel wrote:

>[DS]The current code may be enough for the first time. In case you are
>planning to add an numerical equation solver to GiNaC some extensions may be
>good.
>

Hmm, don't we already have Newton-Raphson implemented in the fsolve() 
function?

:-)
-richy.

-- 
Richard B. Kreckel
<http://www.ginac.de/~kreckel/>



From Chris.Dams at mi.infn.it  Fri Sep  8 17:55:04 2006
From: Chris.Dams at mi.infn.it (Chris Dams)
Date: Fri, 8 Sep 2006 17:55:04 +0200 (CEST)
Subject: [GiNaC-devel] Vladimirs patch has been applied. 
In-Reply-To: <13516.1156186045@localhost>
Message-ID: <Pine.LNX.4.44.0609081751160.30023-100000@lxmi.mi.infn.it>


Dear Vladimir,

On Mon, 21 Aug 2006, Vladimir Kisil wrote:

> 		Many thanks for making the patch. From my side I revised once
>   more clifford.cpp and change some varidx to idx. I also amend
>   exam_clifford.cpp in away which checks metrics given by matrices both
>   with idx and varidx.

This patch has been applied.

Best wishes,
Chris



From Chris.Dams at mi.infn.it  Fri Sep  8 18:02:13 2006
From: Chris.Dams at mi.infn.it (Chris Dams)
Date: Fri, 8 Sep 2006 18:02:13 +0200 (CEST)
Subject: [GiNaC-devel] Bug(?) in reposition_dummy_indices: test case and
	patch
In-Reply-To: <Pine.LNX.4.44.0608301333430.21429-100000@lxmi.mi.infn.it>
Message-ID: <Pine.LNX.4.44.0609081755510.30023-100000@lxmi.mi.infn.it>


Dear all,

On Wed, 30 Aug 2006, Chris Dams wrote:

> What about modifying the canonicalization code in symmetry.cpp, then? We
> could at first decide the canonical form based only on the values and
> dimensions of the indices. Not on their variance. If that does not give a
> prefered ordering we would order them the same way as is done now.  
> Besides that, we should reject a toggling of indices in reposition_dummy
> indices if it results in an expression with reordered indices. Does this
> sound any better?

I now patched the function reposition_dummy_indices to fix this. The idea
is that the problem Alexei pointed out can only occur if there are
varidxes involved in a cyclic symmetry. In that case the function
reposition_dummy_indices now starts by trying out all variations obtained
by raising/lowering varidxes that occur in dummy pairs of the tensor
object that is given to reposition_dummy_indices. Of these posibilities
the one that is the smallest in the sense of ex_is_less is chosen. The
dummy indices that have taken part in this trying out of all posibilities
are removed from the vector variant_dummy_indices. After that there
shouldn't be a problem anymore using the rest of the function
reposition_dummy_indices as it always has been.

Best wishes,
Chris




From Chris.Dams at mi.infn.it  Wed Sep 13 14:48:45 2006
From: Chris.Dams at mi.infn.it (Chris Dams)
Date: Wed, 13 Sep 2006 14:48:45 +0200 (CEST)
Subject: [GiNaC-devel] Unarchiving algorithms of order N.
Message-ID: <Pine.LNX.4.44.0609131446550.22205-100000@lxmi.mi.infn.it>


Dear all,

I noticed that the unarchiving alogithms of container-like classes are of
order N^2. This makes it impossible to unarchive large expressions within
reasonable time. A patch to make this of order N is in CVS.

Best wishes,
Chris