Name: Vladyslav Shtabovenko (email_not_shown)
Date: 05/04/17-01:09:54 PM Z


Hi,

thanks for reporting this.

This is a bug related to the internal caching of DiracTrace: once the
calculated traces are cached with a particular value of $LeviCivtaSign,
setting it to something else does not change the cached results.

Should be now fixed in the stable and in the the development versions.

<https://github.com/FeynCalc/feyncalc/commit/b4bdb78fe3404dad3b5f67bb13332996047080fb>

Please reinstall the stable version via the automatic installer.

Cheers,
Vladyslav

Am 03.05.2017 um 16:22 schrieb JamesG:
> Hi,
>
> Trying to reset the LeviCivita sign conventions appears to me to have no effect when using the definitions above. For example I find that the input
>
> Tr[[GA[a, b, c, d, 5]]
> $LeviCivitaSign = 1;
> Tr[GA[a, b, c, d, 5]]
>
> gives
>
> -4 I Eps[LorentzIndex[a], LorentzIndex[b], LorentzIndex[c],
> LorentzIndex[d]]
>
> independent of whatever else I set $LeviCivitaSign to.
>
> Is there some other way to fix the conventions in the latest version of Feyncalc (9.2); or is this affected by, say, a more recent version of Mathematica (I am currently using 10.1)?
>
> James
>



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