Name: Will (email_not_shown)
Date: 11/08/17-09:19:50 AM Z


Dear Vladyslav,

Thanks for your prompt reply and fixing the issue of the previous message.

I am using FeynHelpers to check IBP relations I have obtained by my own.
Moreover, I guess with the latest update of FIRE repository something didn't go well.

Let me explain with a particular example.
For a one-loop box topology, if I define

FCClearScalarProducts[];
SPD[p[1], p[1]] = 0;
SPD[p[2], p[2]] = 0;
SPD[p[3], p[3]] = 0;
SPD[p[1], p[2]] = s/2;
SPD[p[1], p[3]] = -(s + t)/2;
SPD[p[2], p[3]] = t/2;

and try to reduce a triangle to bubbles, namely

int = FAD[q, q - p[1] - p[2], q - p[1] - p[2] - p[3]]
int// FIREBurn[#, {q}, p /@ Range[3]] &

I get the following error

FCAbbreviate::failmsg: Error! FCAbbreviate has encountered a fatal problem and must abort the computation. The problem reads: Your expression is too complicated to be abbreviated effectively.

But, if I don't define the Maldestam variables,

FCClearScalarProducts[];
SPD[p[1], p[1]] = 0;
SPD[p[2], p[2]] = 0;
SPD[p[3], p[3]] = 0;

Reduction goes well.

The file I was doing this check with is an old one that
worked perfectly with the first releases of Feynhelpers

I would appreciate if you could tell me how to proceed with
these troubles.

Cheers,
Will



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