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Management library for LHAPDF

This a pure-python LHAPDF management library to download, list and load PDFs. At the moment it cannot do any interpolation or perform anything that would need a complete LHAPDF installation.

Install

It can be installed from pypi with a simple command

  pip install lhapdf-management

Features

At the moment is very bare-bones and includes only:

Update

Updates the local reference index

  lhapdf_management update

If no installation of LHAPDF is found, the program will fail to do anything, as creating the LHAPDF directory is not the business of the management module. In order to run lhapdf-management and make it believe that LHAPDF already exist a possibility is to populate the LHAPDF_DATA_PATH environment variable, i.e.,

LHAPDF_DATA_PATH=$(python -c 'from pathlib import Path ; from sys import prefix ; print(Path(prefix) / "share" / "LHAPDF")' ; lhapdf-management update

It is possible to create the directory in the "best guess location" doing lhapdf_management update --init

List

Lists all available PDFs

  lhapdf_management list [PATTERNS ...] [--installed] [--codes]

Install

Installs a given PDF

  lhapdf_management install <pdf_name> [--upgrade] [--keep]

Open a PDF

It can also be used to programatically get an object pointing to all the right parts of a PDF. No interpolation will be provided by this script at this point and when/if it is ever provided will be done by importing the normal python interface of LHAPDF (and so at that point LHAPDF will need to be installed)

  from lhapdf_management.pdfsets import PDF
  from lhapdf_management.configuration import get_lhapdf_datapath
  data_path = get_lhapdf_datapath()
  pdf = PDF(data_path / "NNPDF31_nnlo_as_0118")
  grids = pdf.get_member_grids(0)

Programatically use the interface

A very useful feature of this library is the possibility of using everything programatically. The three given interfaces (install, list and update) take as input the same arguments as the script interface.

  from lhapdf_management import pdf_install, pdf_list, pdf_update
  list_of_pdfs = pdf_list("--installed")
  pdf_install("NNPDF31_nnlo_as_0118")

Download all PDFs matching pattern

There are some arguments that have been modified for simplicity as their behaviour can also be obtained by other means. For instance, in order to download all PDFs matching a certain pattern one can write the following short bash script:

  for pdf in $(lhapdf_management list NNPDF31*)
  do
    lhapdf_management install ${pdf} --upgrade
  done

TODO

While this script can (if needed) be used as is, there are a number of features missing to be compatible with the lhapdf. The list of features that are currently missing with respect to the previous script are:

  • list --outdated
  • install --dryrun