Add NNPDF fitting code

[scarlehoff]

We (meaning the NNPDF collaboration) recently open sourced our PDF fitting code:

https://github.com/NNPDF/nnpdf

The documentation is in: https://docs.nnpdf.science/

As to where to classify it, I guess between xfitter and LHAPDF is the obvious place.

Some other codes (shameless plug):

• PDFFlow: https://github.com/N3PDF/pdfflow, basically a clone of LHAPDF that uses TensorFlow and thus can be used to target GPUs
• MadFlow: https://github.com/N3PDF/madflow an automatic event generator using TensorFlow and which can be used to target GPUs.

I can open a PR with all that if it is easier that way.

[nikosarcevic]

We (meaning the NNPDF collaboration) recently open sourced our PDF fitting code:

https://github.com/NNPDF/nnpdf

The documentation is in: https://docs.nnpdf.science/

As to where to classify it, I guess between xfitter and LHAPDF is the obvious place.

Some other codes (shameless plug):

• PDFFlow: https://github.com/N3PDF/pdfflow, basically a clone of LHAPDF that uses TensorFlow and thus can be used to target GPUs
• MadFlow: https://github.com/N3PDF/madflow an automatic event generator using TensorFlow and which can be used to target GPUs.

I can open a PR with all that if it is easier that way.

yes please if you can do a PR that would be great