Name: Vladyslav Shtabovenko (email_not_shown)
Date: 06/13/17-08:20:38 PM Z


Sorry, wrong attachment. This one is what I was referring to previously.

Cheers,
Vladyslav

Am 13.06.2017 um 20:18 schrieb Vladyslav Shtabovenko:
> Hi,
>
> Am 13.06.2017 um 16:05 schrieb Stefano Colucci:
>> Hi again,
>>
>> and thanks for your prompt answer. Regarding the use of "." : I guess
>> I was mislead by reading in the documentation page for Contract :
>>
>> " The "." as multiplication operator is not necessary but just
>> convenient for typesetting.”
>
> Well, for commutative quantities the ordering in the product clearly
> does not matter, which is what the documentation page is referring to.
>
> For noncommutative quantities one would always use Dot and not Times.
> This is one of the basics of Mathematica (i.e. it has nothing to do with
> FeynCalc per se), so in the documentation it is assumed that this point
> is understood.
>
>>
>> Anyways I followed your suggestions but I still get an error message
>> and no result when calling
>>
>> In[64]:= DiracTrace[AmpF2, DiracTraceEvaluate -> True, West -> True]
>>
>> During evaluation of In[64]:= DiracTrace::ndranomaly: You are using
>> naive dimensional regularization (NDR), such that in D dimensions
>> gamma^5 anticommutes with all other Dirac matrices. In this scheme
>> (without additional prescriptions) it is not possible to compute
>> traces with an odd number of gamma^5 unambiguously. Evaluation
>> aborted! >>
>>
>> Out[64]= $Aborted
>>
>>
>> I have tried to set D->4 before or to use the option West-> True, but
>> no luck so far.
>>
>
> First of all, I do not seem to be able to reproduce this on the latest
> stable version, c.f. attached notebook.
>
> Second, the West option is relevant only when the BMHV scheme is
> activated ($BreitMaison=True). As the message tells you, by default
> FeynCalc uses NDR.
>
> Third, if you do not care whether D is set to 4 or not, why don't you
> calculate everything in 4D from the very beginning. That would be again
> faster.
>
> Cheers,
> Vladyslav
>
>
>
>
>
>
>
>
>> Thanks again for your help,
>>
>> Stefano
>>




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