Hi,
thanks for your bug report. The issue were terms like FV[q1,i3]^2 that
appeared in your expression and led to some confusion in the reduction
algorithm. One could avoid it by applying Contract to the expression by
hand, but there is no harm if TID does this automatically.
This should be now fixed
<https://github.com/FeynCalc/feyncalc/commit/32e1fa1f987e2502e8ae05893139b2c286768dc8>
If you reinstall FeynCalc with
Import["https://raw.githubusercontent.com/FeynCalc/feyncalc/master/install.m"]
InstallFeynCalc[]
you will have the fix automatically included.
Cheers,
Vladyslav
Am 05.04.2016 um 03:23 schrieb YI-Bo Yang:
> Hi,
>
> When I do the following four indices integration
>
> FAD[q1]^2 FAD[-p +
> q1] (Pair[LorentzIndex[li1], Momentum[-p + 2 q1]] Pair[
> LorentzIndex[li3], LorentzIndex[li5]] +
> Pair[LorentzIndex[li1], LorentzIndex[li5]] Pair[LorentzIndex[li3],
> Momentum[2 p - q1]] +
> Pair[LorentzIndex[li1], LorentzIndex[li3]] Pair[LorentzIndex[li5],
> Momentum[-p - q1]]) (Pair[LorentzIndex[li2],
> Momentum[p - 2 q1]] Pair[LorentzIndex[li4], LorentzIndex[li5]] +
> Pair[LorentzIndex[li2], LorentzIndex[li5]] Pair[LorentzIndex[li4],
> Momentum[-2 p + q1]] +
> Pair[LorentzIndex[li2], LorentzIndex[li4]] Pair[LorentzIndex[li5],
> Momentum[p + q1]]) (Pair[LorentzIndex[li3], Momentum[q1]] Pair[
> LorentzIndex[li4], LorentzIndex[li7]] -
> Pair[LorentzIndex[li3], LorentzIndex[li4]] Pair[LorentzIndex[li7],
> Momentum[q1]]) (-Pair[LorentzIndex[li3], LorentzIndex[li8]] Pair[
> LorentzIndex[li3], Momentum[q1]] +
> Pair[LorentzIndex[li3], LorentzIndex[li3]] Pair[LorentzIndex[li8],
> Momentum[q1]])
>
> with TID, an error message appears instead of the result,
>
> Error! TID has encountered a fatal problem and must abort the computation. The problem reads: "Running tidSingleIntegral failed to achieve full tensor reduction of the unique integrals in …”
>
> How can I do to avoid it?
>
> Many thanks for any help,
>
> Yi-Bo
>
>
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