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FeynCalc / feyncalc

Mathematica package for algebraic calculations in elementary particle physics.
https://feyncalc.github.io
GNU General Public License v3.0
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QEDComptonScatteringTree returning the wrong value #26

Closed patha325 closed 7 years ago

patha325 commented 7 years ago

The in feyncalc, included example of a QEDComptonScatteringTree returns the wrong value. Mathematica version 11.0.0.0 Mac OS X x86 (32-bit, 64-bit kernel) Using an out of the box installation of mathematica and feyncalc using Import["https://raw.githubusercontent.com/FeynCalc/feyncalc/master/install.m"]; InstallFeynCalc[]

I would love to know what is wrong since this makes no sense to me at all. It might be the setmandelstram? QEDComptonScatteringTree.pdf

patha325 commented 7 years ago

Full reinstall of mathematica sorted things out. Must have been something wrong with the installer?

vsht commented 7 years ago

Your version of QEDComptonScatteringTree.m looks a bit weird. In particular, the line 

SetMandelstam[s, t, u, p1, k1, -p2, -k2, SMP["m_e"], 0];

is not correct. Compare this to how it should look like. Did you modify the example file yourself before running it?

I use Mathematica 11.0 myself (albeit on Linux) and I usually run all available tests and examples before pushing anything into the hotfix-stable branch, which is what automatic installer uses.

So far there were no complaints about automatic installer fetching wrong files. At most I could imagine that if you first use the installer and then try to clone git repository in the same directory, there might be unwanted interference. However, for people who want to use git themselves, there is a separate section in the wiki, that does not require the installer.

patha325 commented 7 years ago

Dear Sir, I did not edit anything before running it but as I added when closing the thread a full reinstall solved this issue.

Since I used the automatic installer, that is where I would assume the fault came from. But I am grasping at straws.

MVH/Kind regards Patrik Hallsjö

2017-04-11 17:36 GMT+02:00 Vladyslav Shtabovenko notifications@github.com:

Your version of QEDComptonScatteringTree.m looks a bit weird. In particular, the line

SetMandelstam[s, t, u, p1, k1, -p2, -k2, SMP["m_e"], 0];

is not correct. Compare this to how it should look like https://github.com/FeynCalc/feyncalc/blob/hotfix-stable/FeynCalc/Examples/QED/QEDComptonScatteringTree.m#L57 . Did you modify the example file yourself before running it?

I use Mathematica 11.0 myself (albeit on Linux) and I usually run all available tests and examples before pushing anything into the hotfix-stable https://github.com/FeynCalc/feyncalc/tree/hotfix-stable branch, which is what automatic installer uses.

So far there were no complaints about automatic installer fetching wrong files. At most I could imagine that if you first use the installer and then try to clone git repository in the same directory, there might be unwanted interference. However, for people who want to use git themselves, there is a separate section https://github.com/FeynCalc/feyncalc/wiki/Installation#dev_manual_installation_with_git_on_linux in the wiki, that does not require the installer.

— You are receiving this because you modified the open/close state. Reply to this email directly, view it on GitHub https://github.com/FeynCalc/feyncalc/issues/26#issuecomment-293302896, or mute the thread https://github.com/notifications/unsubscribe-auth/AGefejy1Tw626o-OW8LK1a_PPa2RuIP8ks5ru531gaJpZM4M5UC5 .

vsht commented 7 years ago

In this case I really don't know. The installer essentially downloads https://github.com/FeynCalc/feyncalc/archive/hotfix-stable.zip from GitHub and extracts it to the right directory using Mathematica's ExtractArchive. I cannot easily think of anything going wrong there. In any case, if you manage to make the issue reproducable, let me know.