Add spearman correlation

[gautamramk]

It would be useful to add Spearman Correlation to the similarities module. It is very similar to Pearson's correlation, except a rank is used, instead of ratings.

[gautamramk]

Shall I work on it?

[NicolasHug]

Sure go ahead :)

[ghost]

Hello @gautamramk ,

you're still working on this issue?.

If not, then I would like to take over.

Yours sincerely
Marc Feger

[ghost]

Hey @NicolasHug,
I think I can take over the task because there's been no response for three days.

Can you please assign me to the issue?

[NicolasHug]

Sure.

Have you looked at #168? It seems that the bulk of the work is done already and what's left is a benchmark to assess how fast / accurate spearman would be.

[NicolasHug]

Hmm looks like I cannot assign you to the issue because you don't have write rights. It's not important though so don't worry.

[ghost]

All right, all right.

I see @gautamramk is working with a fork.
So should I copy the code and improve it?
Or should I fork the fork? :D

What would be a good procedure here ?

[ghost]

Or can the PR be added to another branch in this project so that I can work from my fork ?

[NicolasHug]

I think a good way to do it would be to pull the PR branch (look here) in your own fork / clone.

Then you can either directly work on this local branch of yours, or branch off it to keep it clean (that's what I do).

You'll still need to make a new PR though.

[ghost]

Ah okay, I understand.

Thanks for the hint.

[ghost]

Okay done !
I will work on it.

This worked out well:

git fetch surprise_origin pull/168/head:spearman
git checkout spearman
git push origin spearman