html_url,issue_url,id,node_id,user,created_at,updated_at,author_association,body,reactions,performed_via_github_app,issue
https://github.com/pydata/xarray/issues/1332#issuecomment-418161473,https://api.github.com/repos/pydata/xarray/issues/1332,418161473,MDEyOklzc3VlQ29tbWVudDQxODE2MTQ3Mw==,1217238,2018-09-03T16:56:26Z,2018-09-03T16:56:26Z,MEMBER,"I agree that we should have a ""middle"" or ""centered"" option for xarray.diff.
On Mon, Sep 3, 2018 at 9:14 AM T. Chor <notifications@github.com> wrote:

> I'm not sure where we stand on this issue, but I think since
> numpy.gradient already exists, it makes more sense to wrap that function
> for the sake of simplicity instead of making xr.diff differ from the
> original premise of np.diff.
>
> On the same topic, it bothers me that xr.diff only accepts ""upper"" and
> ""lower"" arguments for the label. The most obvious (and useful) value in
> my opinion would be ""middle"", which would correspond to a centered finite
> differences. Is there any special reason why that option isn't there?
>
> —
> You are receiving this because you were mentioned.
> Reply to this email directly, view it on GitHub
> <https://github.com/pydata/xarray/issues/1332#issuecomment-418154705>, or mute
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> .
>
","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,217385961
https://github.com/pydata/xarray/issues/1332#issuecomment-289859704,https://api.github.com/repos/pydata/xarray/issues/1332,289859704,MDEyOklzc3VlQ29tbWVudDI4OTg1OTcwNA==,1197350,2017-03-28T18:21:17Z,2017-03-28T18:21:17Z,MEMBER,"> @rabernat, do you think that the proposed keyword additions should be included in xarray or not?

If you are going to have `diff` return a same-length array, then the keywords should allow the user to specify the boundary condition, e.g. extend, reflect, periodic, blank, etc. I agree this would be useful to have in xarray.

I also agree we should copy numpy wherever possible.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,217385961
https://github.com/pydata/xarray/issues/1332#issuecomment-289858583,https://api.github.com/repos/pydata/xarray/issues/1332,289858583,MDEyOklzc3VlQ29tbWVudDI4OTg1ODU4Mw==,1217238,2017-03-28T18:17:18Z,2017-03-28T18:17:18Z,MEMBER,"As I mentioned in #1288, I think basic functionality like `integrate` and `gradient` is totally within appropriate scope for xarray.

I recall now that people have requested similar functionality for `numpy.diff`: https://github.com/numpy/numpy/issues/8132. It would be nice to resolve this upstream in NumPy first (e.g., with https://github.com/numpy/numpy/pull/8206), and then simply copy the API design in xarray.","{""total_count"": 2, ""+1"": 2, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,217385961
https://github.com/pydata/xarray/issues/1332#issuecomment-289839737,https://api.github.com/repos/pydata/xarray/issues/1332,289839737,MDEyOklzc3VlQ29tbWVudDI4OTgzOTczNw==,1197350,2017-03-28T17:13:00Z,2017-03-28T17:13:00Z,MEMBER,"> It is just super inconvenient to do array resizing following the diff of a time vector to get timesteps, but maybe this use case is too niche to be useful for the community.

Maybe for the xarray community, but not the xgcm community ;) We definitely want round-trip-compatibly diff and cumsum operations (see xgcm/xgcm#49, which is very close to implemented)
","{""total_count"": 1, ""+1"": 1, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,217385961
https://github.com/pydata/xarray/issues/1332#issuecomment-289790359,https://api.github.com/repos/pydata/xarray/issues/1332,289790359,MDEyOklzc3VlQ29tbWVudDI4OTc5MDM1OQ==,1197350,2017-03-28T14:35:41Z,2017-03-28T14:35:41Z,MEMBER,"FYI @pwolfram, if you are interested in more ""grid-aware"" finite differencing, you might have a look at xgcm. We are working on it again and have implemented some basic difference and interpolation operators:
http://xgcm.readthedocs.io/en/latest/grids.html#grid-objects ","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,217385961
https://github.com/pydata/xarray/issues/1332#issuecomment-289671227,https://api.github.com/repos/pydata/xarray/issues/1332,289671227,MDEyOklzc3VlQ29tbWVudDI4OTY3MTIyNw==,1217238,2017-03-28T05:56:57Z,2017-03-28T05:56:57Z,MEMBER,"Would it fill the same need to add a wrapped version of `np.gradient`, which already works similarly to `diff` but preserves input shape?","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,217385961