UsePaVeBasis enters the stage only if the input contains
tensor integrals. In your case there are none, so nothing
happens.
ToPaVe is applied to any output at the very end, hence, the
conversion still occurs.
There can be also cases where despite having
UsePaVeBasis->True you will still get some scalar integrals
as FADs, since those arose through partial fractioning before
the actual tensor reduction.
Using
TID[amp,k1,UsePaVeBasis->True, ToPaVe->True]
will ensure that all loop integrals in the output are always written
as PaVe functions.
Cheers,
Vladyslav
Am 02.03.20 um 17:00 schrieb Jorge C. Rom�o:
> I am moving from OneLoop to TID. However, consider
>
> amp=FAD[{k1, m1}, {k1 - p1, m2}, {k1 - q1, m3}, q2 + q3]
>
> which appears in a non irreducible diagram. Now
>
> TID[amp,k1,ToPaVe->True]//FCE//InputForm =
> I*Pi^2*C0[SPD[p1, p1], SPD[q1, q1], SPD[p1, p1] - 2*SPD[p1, q1] + SPD[q1, q1], m2^2, m1^2, m3^2]*FAD[q2 + q3]
>
> as it should. However
>
> TID[amp,k1,UsePaVeBasis->True]//FCE//InputForm
> =FAD[q2 + q3]*FAD[{k1, m1}, {k1 - p1, m2}, {k1 - q1, m3}]
>
> that is does nothing!
>
> This is a piece inserted in a large code and one does not want to look at each term and want to use UsePaVeBasis->True to get fewer terms.
>
> Best
>
> Jorge
>
>
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