How to install and use FeynArts?

Question

I want to be able to use both FeynCalc and FeynArts (together seems impossible, I'm fine with using them separately for now). I don't know how to install FeynArts and run the simplest examples. I tried Import["http://www.feyncalc.org/install.m"] which fetches FeynCalc and FeynArts but I cannot use this FeynArts for some reason. I cannot load it in Mathematica 10 (Mac OSX).

When I follow this site's suggestion

A dialog asking if you want to patch FeynArts will appear. Type yes and hit OK. Wait until the patching process finishes

This dialoge never appears in my case, but only an error message saying:

$LoadPhi = True; $LoadFeynArts = True; <<HighEnergyPhysics`FeynCalc`; 
Loading FeynCalc from /Users/MyName/Library/Mathematica/Applications/HighEnergyPhysics
FeynCalc 8.2.0 For help, type ?FeynCalc, open FeynCalcRef8.nb or visit www.feyncalc.org
Loading PHI 
WARNING! Your FeynArts installation is not complete or the version you have cannot be used with this version of FeynCalc.
FeynArts can be downloaded at www.feynarts.de
Loading FeynArts, see www.feynarts.de for documentation
FeynArts not found. Please install FeynArts, e.g., in
/Users/MyName/Library/Mathematica
and reload FeynCalc
FeynArts can be downloaded from www.feynarts.de

Any suggestions?

Answer 1

Hmm, actually I thought that I wrote it in the wiki in a pretty clear way.

For FeynCalc 9.0: https://github.com/FeynCalc/feyncalc/wiki/FeynArts#patching_fa2

For FeynCalc 8.2: https://github.com/FeynCalc/feyncalc/wiki/FeynArts#patching_fa

FeynCalc 9.0 is still in development (Development version), but will be released until the end of this year. The GitHub repository is regularly updated with bugfixes. The installation is also quite straight forward

https://github.com/FeynCalc/feyncalc/wiki/Installation#development_version

This dialoge never appears in my case, but only an error message saying:

This is because you applied the instruction for FC 9.0 to FC 8.2. No wonder that it didn't work.

Answer 2

Here's a short-worded solution for Mac OSX Mathematica 10.

I am sure there are smoother ways to fix this but this worked for me:

Autoinstall FeynCalc directly from Mathematica 10 by writing

Import["http://www.feyncalc.org/install.m"]

This will create a directory in /Users/Yourname/Library/Mathematica/Applications. The name of the directory will be HighEnergyPhysics and it will contain a lot of files and other directories, including one called FeynArts-3.7.

Now what I did was deleting this FeynArts-3.7 folder and replacing it with FeynArts-3.9 which you can download if you search the net for it. Following the instructions on the FeynArts.de page I saved a file called FeynInstall. Using the Terminal I made it executable by writing in the Mac terminal chmod 755 FeynInstall. The file that was created with this command I copied to the folder called /Users/Yourname/Library/Mathematica/Applications/HighEnergyPhysics/FeynArts-3.9.

Finally I simply double clicked on FeynInstall and it asked me a bunch of question...I simply hit return until something happened.

Now I restart Mathematica and write $LoadPhi = $LoadTARCER = False; followed by $LoadFeynArts = True; and then finally I write

<< HighEnergyPhysics`FeynCalc` 

A simple first example can go like:

CreateTopologies[1, 1->1];
Paint[%]