-
Notifications
You must be signed in to change notification settings - Fork 136
New issue
Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.
By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.
Already on GitHub? Sign in to your account
Vacuum diagrams using diagrams_() #485
Comments
Indeed it seems that |
It seems like Concerning the `diagrams_' command, the error persists. I have not done further checking than the zero-external leg diagrams. But having this feature to reliably generate bubble diagrams directly would certainly also be desirable in a future version. |
Just wondering which version of the algorithm is implemented. The manual refers this paper but the paper says in its introduction
though how to loosen this restriction is described in Section 6. |
Testing the new diagram generation function in FORM 5.0-beta.1 with QCD, as a specific model, I ran into the result below.
I am specifically trying to generate vacuum diagrams i.e. diagrams that have zero external legs. While symmetry factors seem to be correct, at 2loop level it seems that not all topologies are covered. Here e.g. only one topology is generated which is the sunset diagram. Although at 2loop level I would have also expected there to be another topology, the figure 8 diagram.
A similar situation appears when going to 3loops. Also not all the particle content seems to be used and only a fully gluon mercedes diagram is generated while there should also be mercedes diagrams with fermion and ghost content.
Additionally I noticed that the print statement did not work for me in this version -- I had to use
#write
to see any output.Also the commented bracketing command
b s1;
caused the script to terminate.The text was updated successfully, but these errors were encountered: