Name: Rolf Mertig (email_not_shown)
Date: 12/10/04-12:12:28 AM Z


Hola,
now it takes again only a few minutes.
The reason is that similar optimizations as I show in the attached
notebook were automatically done in the older FeynCalc;
however, some optimizations caused wrong results and therefore they were
abandoned.
Anyway: it is always a good idea to think a bit about the algorithms and
to fiddle with some useful functions like Isolate and Collect and alike.
Saludos,

Rolf Mertig

Dr. Jaime Hernandez Sanchez;icbi wrote:

>DEAR MERTIG;
>
>I STILL HAVE TROUBLES WITH TRACES
>
>I SEND A SMALL PROGRAM THAT ALREADY I HAVE CHECKED WELL IN ANOTHER MACHINE.
>
>THE CALCULATION OF THE TRACES THEY ARE REALIZED IN A FEW MINUTES ON MATHETAICA 4.1.
>
>THE SAME CALCULATION I DO IT IN MATHEMATICA 5 AND IT WAS RUNNING MANY HOURS AND
>BETTER I ABORT.
>
>PLEASE CHECK THE PROGRAM Y MAKE ME A RECOMENDANTION.
>
>JAIME
>
>On Thu, 09 Dec 2004 00:25:45 +0100, Rolf Mertig wrote
>
>
>>Dear Jaime,
>>
>>Dr. Jaime Hernandez Sanchez;icbi wrote:
>>
>>
>>
>>>Dear Mertig:
>>>
>>>i have several problems with Feyncal.
>>>
>>>I have mathematica 5 on mac-g5`s plataform.
>>>
>>>Firts, when i run FeynCalc, It gives the following result
>>>
>>>DumpGet::bgbf: File \
>>>/Library/Mathematica/Applications/HighEnergyPhysics/Tarcer/tarcer25.mx cannot \
>>>be loaded, it is corrupted or is written on a different machine
>>>
>>>
>>>
>>>
>>Please evaluate in an emtpy notebook (without loading FeynCalc):
>>
>>SetDirectory["/Library/Mathematica/Applications/HighEnergyPhysics/Tarcer/"];
>>NotebookOpen["/Library/Mathematica/Applications/HighEnergyPhysics/Tarcer/Tarcer.nb"];
>>
>>Then evaluate the whole notebook.
>>This will produce a new "tarcer25.mx" (or similar, depending on the
>>setting of $RankLimit )
>>
>>
>>
>>>I have tried to replace the file tarcer25.mx by tarcer23.mac.mx from web page
>>>mertig.com, however
>>>
>>>it gives other mistake.
>>>
>>>Second
>>>
>>>I have tried to run some simple programs and to verify that they are correct, for
>>>example
>>>
>>>a trivial exercise
>>>
>>>FullSimplify[TR[(GS[k] + m).(GA[mu]).(GS[p] - m).GA[nu]]]
>>>
>>>it gives a correct result
>>>
>>>but
>>>
>>>TR[(GS[p1] + m).(GA[mu].GS[k].GA[ nu] + 2 GA[mu] FV[p2, nu]).(GS[p2] +
>>>
>>>
>m).(GA[nu].GS[k].GA[mu] +
>
>
>>>2 GA[mu] FV[p2, nu])]
>>>
>>>mathamatica does not give a correct result.
>>>
>>>
>>>
>>>
>>This is a bug (probably introduced when fixing other bugs last year).
>> It should only occur if you call TR on unsimplified noncommutative
>>expressions directly.
>>A quick workaround is to use "tr" instead of TR, with
>>
>>tr = TR[Calc[#]] &;
>>
>>I am planning to fix FeynCalc - bugs (and some error messages
>>showing up when loading FeynCalc in Mathematica 5.1 ) together with
>>Frederik before Christmas, but I cannot fix them right now.
>>
>>Sorry about the trouble.
>>
>>Saludos,
>>
>>Rolf Mertig
>>
>>GluonVision GmbH
>>Berlin
>>
>>
>>
>>>I need your help.
>>>
>>>
>>>Regards
>>>
>>>
>>>Jaime
>>>
>>>
>>>--
>>>Universidad Autonoma del Estado de Hidalgo
>>>Centro de Investigacion Avanzada en Ingenieria Industrial
>>>Licenciatura en Fisica y Tecnologia Avanzada
>>>Pachuca, Hidalgo. C. P. 42090
>>>Tel y Fax: (771)7172000 ext. 6733
>>>
>>>
>>>
>>>
>
>
>--
>Universidad Autonoma del Estado de Hidalgo
>Centro de Investigacion Avanzada en Ingenieria Industrial
>Licenciatura en Fisica y Tecnologia Avanzada
>Pachuca, Hidalgo. C. P. 42090
>Tel y Fax: (771)7172000 ext. 6733
>
>




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