Add a typed mode operator.

[cdepillabout]

This PR adds a typed mode operator, as per #233.

I just talked to @tscholak, and he suggested that I should check that this operator actually works on CUDA. I don't have an nvidia GPU, so I haven't done this, but I would appreciate if someone could check this for me.

Also, because I added the doctests, I didn't add any hspec tests, but I could do this if necessary.

(Note that this PR is based on the current master, which does not yet contain a fix for actually running the doctests in CI, but I did check that the doctests I added here run correctly locally.)

[cdepillabout]

Here's the pytorch docs for mode just in case: https://pytorch.org/docs/stable/torch.html#torch.mode

[junjihashimoto]

Thx! CUDA's test is here.
https://github.com/hasktorch/hasktorch/blob/master/hasktorch/test/Torch/Typed/FunctionalSpec.hs

[cdepillabout]

@junjihashimoto Thanks for the pointer.

So you're suggesting that I add a CUDA-enabled test for mode to
https://github.com/hasktorch/hasktorch/blob/master/hasktorch/test/Torch/Typed/FunctionalSpec.hs, and then ask someone to run the test suite on a machine with an nvidia GPU?

[junjihashimoto]

Yes, I have native GPU.

[junjihashimoto]

Or we can do a test after merging.
It's in the cache so we can easily test it.

[junjihashimoto]

Is there a good way? The test of gpu is ideally done on ci.
You can check it at the colaboratory, but it's troublesome.

[austinvhuang]

LGTM, more testing esp on gpu is always helpful but I also think it's relatively low risk having the same form as median / mean.

[junjihashimoto]

Yeah, the risk is low. Do you want to merge? I think we can add another PR for hspec.

[tscholak]

Hi all, there are some minor issues with this, but we can merge as is.
I’ve started working on the hspec tests in another branch.

[cdepillabout]

@tscholak @junjihashimoto Sorry, I should have replied here earlier, but I was working on writing the hspec tests locally, but I didn't yet have anything I felt comfortable pushing.

When @tscholak opens a PR for the hspec tests, I'll try to take a look and figure out what I could have done differently in this PR.

[tscholak]

Hi @cdepillabout, no problem! We are very glad you made this contribution, thanks a lot!
I’ve found some issues in the typed FunctionalSpec suite that are not all related to the mode function. I’m in the middle of sorting them out, expect a PR tomorrow :)