Document functions

[cheater]

Maybe write short one liners that tell users what things like berhu, huber, quadform, hmax, hmin do - they are difficult to understand like that. Giving a link to a wikipedia article for further explanation is good too.

[chrisnc]

hmin and hmax are just min and max, but named so as not to conflict with the definitions in the Prelude.

huber is the Huber loss function: quadratic loss for small |x|, and linear elsewhere.
Described here: https://en.wikipedia.org/wiki/Huber_loss

berhu is the reverse Huber loss function. Linear loss for small |x|, and quadratic elsewhere. The name is borrowed from CVX: https://github.com/cvxr/CVX/blob/master/functions/berhu.m

quadform is the quadratic form: x'*Q*x for vector x and matrix Q, which is convex if Q is positive definite, but can't be recognized as such in DCP without the quadform primitive.

If you would like to open a PR to add docstrings for these and others that would be to your liking, I will happily merge it, but I don't really have the time or the will to actively maintain this project.

[cheater]

thanks for the info, that's good enough for me for now. I'll leave the issue open so these may be added as doc strings in the future.