Evolution script

The Colibri evolution script is a wrapper around the evolven3fit script that only allows for the evolve option. (See the colibri.scripts.evolve_fit module and the colibri.scripts.evolve_fit.main() function).

It can be executed from the command line as follows:

evolve_fit <name_fit>

where <name_fit> is the name of the fit you want to evolve. The script also has a --help option that will show you all the options available. If the performed fit is a fit which requires ErrorType=hessian, i.e. the PDF grids to evolve are eigenvectors of the covariance matrix, you can specify the option

evolve_fit <name_fit> --hessian_fit True

to correctly produce the LHAPDF set. For more information on the evolution see also the helper from the evolven3fit script.

Postfit emulation

For Bayesian fits, we don’t do any postfit selection on the posterior. However, for backwards compatibility with the validphys module, we still run a postfit emulation which takes care of creating the central replica and a postfit folder containing the evolved replicas as well as the corresponding LHAPDF set.

Upload of the fit

After running the evolution script, it is possible (if you have the right permissions) to upload the fit to the validphys server using the validphys script:

vp-upload <name_fit>

After which the fit can be installed and made available in the environment with the following command:

vp-get fit <name_fit>

If you don’t have the right permissions, we recommend that you symlink the LHAPDF set to the LHAPDF environment folder or to symlink the fit folder to the NNPDF/results folder of your environment.

Note

The final folder after the evolution will also contain a symlink nnfit -> replicas needed for validphys and evolven3fit, as well as a postfit folder.