[special] add zeta

[kshitij12345]

Reference #50345

zeta was already present in the codebase to support computation of polygamma.

However, zeta only had double(double, double) signature for CPU before the PR (which meant that computation polygamma were always upcasted to double for zeta part).

With this PR, float computations will take place in float and double in double.

Have also refactored the code and moved the duplicate code from Math.cuh to Math.h

Note: For scipy, q is optional, and if it is None, it defaults 1 which corresponds to Reimann-Zeta. However, for torch.specia.zeta, I made it mandatory cause for me it feels odd without q this is Reimann-Zeta and with q it is the general Hurwitz Zeta. I think sticking to just general made more sense as passing 1 for q sounds trivial.

Verify:

• Docs https://14234587-65600975-gh.circle-artifacts.com/0/docs/special.html#torch.special.zeta

[facebook-github-bot]

💊 CI failures summary and remediations

As of commit a5aa475 (more details on the Dr. CI page and at hud.pytorch.org/pr/59623):

---

• 3/3 failures possibly* introduced in this PR
  • 1/3 non-scanned failure(s)

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🕵️ 1 new failure recognized by patterns

The following CI failures do not appear to be due to upstream breakages:

pytorch_linux_xenial_cuda11_1_cudnn8_py3_gcc7_build (1/1)

Step: "Build" (full log | diagnosis details | 🔁 rerun)

Jun 24 00:03:41 rm: cannot remove '/var/lib/jenkins/sccache_error.log': No such file or directory

Jun 24 00:03:41 ++++ extract_trap_cmd
Jun 24 00:03:41 ++++ printf '%s\n' ''
Jun 24 00:03:41 +++ printf '%s\n' cleanup
Jun 24 00:03:41 ++ trap -- '
Jun 24 00:03:41 cleanup' EXIT
Jun 24 00:03:41 ++ [[ pytorch-linux-xenial-cuda11.1-cudnn8-py3-gcc7-build != *pytorch-win-* ]]
Jun 24 00:03:41 ++ which sccache
Jun 24 00:03:41 ++ sccache --stop-server
Jun 24 00:03:41 ++ true
Jun 24 00:03:41 ++ rm /var/lib/jenkins/sccache_error.log
Jun 24 00:03:41 rm: cannot remove '/var/lib/jenkins/sccache_error.log': No such file or directory
Jun 24 00:03:41 ++ true
Jun 24 00:03:41 ++ [[ -n '' ]]
Jun 24 00:03:41 ++ [[ pytorch-linux-xenial-cuda11.1-cudnn8-py3-gcc7-build == *rocm* ]]
Jun 24 00:03:41 ++ SCCACHE_ERROR_LOG=/var/lib/jenkins/sccache_error.log
Jun 24 00:03:41 ++ SCCACHE_IDLE_TIMEOUT=1200
Jun 24 00:03:41 ++ RUST_LOG=sccache::server=error
Jun 24 00:03:41 ++ sccache --start-server
Jun 24 00:03:41 sccache: Starting the server...
Jun 24 00:03:41 ++ sccache --zero-stats
Jun 24 00:03:41 Compile requests                      0

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1 failure not recognized by patterns:

Job	Step	Action
pytorch_linux_bionic_py3_8_gcc9_coverage_test1	Run tests	🔁 rerun

---

1 job timed out:

• pytorch_linux_xenial_cuda11_1_cudnn8_py3_gcc7_build

---

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[kshitij12345]

Had to add tolerance based on CI failures (for jobs with relatively old compilers).

https://app.circleci.com/pipelines/github/pytorch/pytorch/338469/workflows/db193abd-5b89-405a-9987-f4926107e2ec/jobs/14225591

https://app.circleci.com/pipelines/github/pytorch/pytorch/338469/workflows/db193abd-5b89-405a-9987-f4926107e2ec/jobs/14224886

[mruberry]

cc @pmeier for yet another example of binary elementwise testing we should automate

[mruberry]

Smart.

One goal of our "writing ops in Python" project (which we're looking at for H2 2021) is to simplify supporting scalar x tensor and tensor x scalar operations, possibly by automating the generation of those functions

[mruberry]

Another great, thorough, careful PR @kshitij12345!

[mruberry]

@kshitij12345 would you just merge this and ping me?

[facebook-github-bot]

@mruberry has imported this pull request. If you are a Facebook employee, you can view this diff on Phabricator.

[kshitij12345]

@mruberry Done :)

[facebook-github-bot]

@mruberry has imported this pull request. If you are a Facebook employee, you can view this diff on Phabricator.

[facebook-github-bot]

@mruberry merged this pull request in dfd2edc.