Developper setup in contributing guidelines

[zaccharieramzi]

Hi,

I would like to contribute to the repo.
I could not find any instructions on how to setup my dev. env. like what linter is used and with which parameters (for example I see that you use 2 spaces identation like all google projects).

By any chance do you have that setup described somewhere? Happy to make a PR with it to include it in the contributing guidelines.

[mblondel]

We have some developer documentation here but we don't enforce a particular coding style yet. Feel free to submit PRs anyway :)

[zaccharieramzi]

Yes yes ofc! It's just that I have VSCode screaming at me with red underlines for the 2 spaces indentation and I was wondering if maybe there was a .flake8 config file that I could use.
But yes submitted the PR anyway (#320)!

[mblondel]

You have a failure in common_test.py due to the fact that state attributes need to be arrays, even when they are a scalar. So you should make gamma an array of size 1. Apart from that, this looks good to me. Could you squash commits so we can merge a clean commit?

[zaccharieramzi]

Ah I only looked at lbfgs tests on my laptop sorry! Correcting right away.

I will squash the commits but there is an option on GitHub to do squash merge (and even an option at the repository level to force all merges to be squashed).

[mblondel]

We don't rely on github to merge but on a bot and we have to manually squash, sorry.