Code review comment for lp:~maddevelopers/mg5amcnlo/2.6.3_optimizenlomodel

Nevermind, I worked it out again and realised what you did is basically the best you can get already. In general, if you have this interaction:

particles = [p.A, p.B, p.C]
color = ['C1','C2']
lorentz = [L.LA, L.LB, L.LC]
couplings = {
(0,0): C.G1, (0,1): C.G2, (0,2): C.G3,
(1,0): C.G4, (1,1): C.G5
}

you can generalise your procedure by defining the following two Lorentz structure being basically:

L.LA + (C.G2/C.G1)*L.B + (C.G3/C.G1)*L.C

and

L.LA + (C.G5/C.G4)*L.B

But I now realise that it's pointless/hard to do this if (C.G<i>/C.G<j>)=K , with K having model parametric dependence. You implemented this for K= +/-1, and in principle it could be extended to any integer, but that has very little value in practice indeed.
So I agree, what you did is already basically the best you can get already.

Cheers