Discovery of existing LHAPDF is not working

[felixhekhorn]

However, by default it should already reuse your existing LHAPDF directory. Are you telling me that isn't the case? That would be considered a bug.

$ cat .bashrc | grep -i lhapdf
# LHAPDF
export LHAPDF_DATA_PATH=/home/felix/local/share/LHAPDF/

but it was not working

[cschwan]

Can you please try deleting your existing managed-lhapdf.toml (probably in ~/.config/) and running pineappl convolve ...? Then it should be in there.

[felixhekhorn]

pineappl convolve ... created that file in the first place - but it did with the defaults and they were not what I wanted;

just to tell the full story: I did run pineappl convolve ... and it took forever and I was surprised and then I concluded the only problem could be with the PDFs and I remembered that you introduced this library here. Then I came here and check the code for the file name and from there I could guess what the parameter do 🙃

[felixhekhorn]

i.e. I changed the file to

$ cat .config/managed-lhapdf.toml 
lhapdf_data_path_read = ["/home/felix/local/share/LHAPDF"]
lhapdf_data_path_write = "/home/felix/local/share/LHAPDF"
pdfsets_index_url = "https://lhapdfsets.web.cern.ch/current/pdfsets.index"
pdfset_urls = ["https://lhapdfsets.web.cern.ch/current/"]

[cschwan]

pineappl convolve ... created that file in the first place

which version did you use? Please paste the output of pineappl --version here.

[felixhekhorn]

$ pineappl --version
pineappl 0.8.2

and just to double check, I just moved the existing file and reran $ pineappl convolve ... which resulted into a TOML file with

lhapdf_data_path_read = ["/home/felix/local/share/LHAPDF/"]
lhapdf_data_path_write = "/home/felix/.local/share/managed-lhapdf"

which, maybe I think, is different from what I got before(?) - which might have been master instead ...

In any case, I would prefer to have also _write point to the ENV var as I put it there consciously and it can only be one dir.

[cschwan]

I already implemented that in commit b6264b5, but I'd have to make a release for it to be used by PineAPPL. The reason I didn't use LHAPDF_DATA_PATH before was that you can give multiple directories, separated by :, and then it is unclear which directory one should write to. However, I agree that we should take over the user's defaults, and I think using the first directory is a good compromise. Most people will probably have exactly one directory in the environment variable anyway.