FeynCalc Phi4 example error with FeynRules

Question

I'm starting on FeynCalc and was trying to run through a few examples coming with the package. For the ones of which the models are generated by FeynRules, it doesn't work out well. (When the model is included in the FeynCalc package, it works fine.) I read somewhere that there might be some incompatibility between FeynRules and Mathematica 11 and not for previous versions. I'm using Mathematica 12.2; could that be the problem or is it due to something else? Attached is the code..ps. I already evaluated the GenerateModelPhi4.m as the documentation suggested. Thanks in advance!

MakeBoxes[p1,TraditionalForm]:="\!\(\*SubscriptBox[\(p\), \      (1\)]\)";
MakeBoxes[p2,TraditionalForm]:="\!\(\*SubscriptBox[\(p\), \(2\)]\)";
MakeBoxes[k1,TraditionalForm]:="\!\(\*SubscriptBox[\(k\), \(1\)]\)";
MakeBoxes[k2,TraditionalForm]:="\!\(\*SubscriptBox[\(k\), \(2\)]\)";

diags = InsertFields[CreateTopologies[1, 2 -> 2,
    ExcludeTopologies->{WFCorrections}],
    {S[1],S[1]}-> {S[1],S[1]}, InsertionLevel -> {Classes},
    Model -> FileNameJoin[{"Phi4","Phi4"}]];
Paint[diags, ColumnsXRows -> {3, 1}, Numbering ->       None,SheetHeader->None, ImageSize->{512,256}];

Answer 1

I've cleared the issue. The error comes from running the model generating file and the actual calculation on the same Kernel. To solve it, one just opens a separate Kernel to do the calculations.

Answer 2

By the way, here I want to also illustrate those messages about $CharacterEncoding.

The FeynRules package is writing files with OpenWrite, but didn't set the CharacterEncoding for it. As the metadata in this model file includes european diacritical characters, they were encoded like CharacterEncoding -> WindowsANSI.

And the FeynArts package is reading model files with Get, which defaults to use $CharacterEncoding, it won't be able to read a WindowsANSI encoded file if you've set it to UTF8 etc. .