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/pull/4193#issuecomment-677461194,https://api.github.com/repos/pydata/xarray/issues/4193,677461194,MDEyOklzc3VlQ29tbWVudDY3NzQ2MTE5NA==,10194086,2020-08-20T08:37:47Z,2020-08-20T08:37:47Z,MEMBER,thanks @aulemahal!,"{""total_count"": 1, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 1, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,650044968
https://github.com/pydata/xarray/pull/4193#issuecomment-675046525,https://api.github.com/repos/pydata/xarray/issues/4193,675046525,MDEyOklzc3VlQ29tbWVudDY3NTA0NjUyNQ==,20629530,2020-08-17T18:42:51Z,2020-08-17T18:42:51Z,CONTRIBUTOR,@mathause Fixed the tests to catch the warning and added a case for the specific of the issue : too many nans causing a rank deficiency. ,"{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,650044968
https://github.com/pydata/xarray/pull/4193#issuecomment-674719063,https://api.github.com/repos/pydata/xarray/issues/4193,674719063,MDEyOklzc3VlQ29tbWVudDY3NDcxOTA2Mw==,10194086,2020-08-17T07:43:50Z,2020-08-17T07:43:50Z,MEMBER,"Pity that the dask warnings are not caught but I guess there's not much we can do about that.

Does this now work for the originally posted issue? Could you add it as a test? ","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,650044968
https://github.com/pydata/xarray/pull/4193#issuecomment-674153884,https://api.github.com/repos/pydata/xarray/issues/4193,674153884,MDEyOklzc3VlQ29tbWVudDY3NDE1Mzg4NA==,20629530,2020-08-14T16:23:12Z,2020-08-14T16:23:35Z,CONTRIBUTOR,"So while adding tests, I realized there were more bugs concerning deficient rank matrices and `full=True` output. I believe I fixed all I could find. 
However, I was not able to reduce the number of warnings for the case using dask : the computation occurs outside of the `catch_warnings()` context...
Also, there is a bug in the `dask.array.linalg.lstsq` output (see issue dask/dask#6516), so if `full=True` we must use  `skipna=True` with dask.  Same when rank != order (deficient rank), `dask.array.linalg.lstsq` will fail, so we work around by using our (slower) nan-skipping method.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,650044968
https://github.com/pydata/xarray/pull/4193#issuecomment-673978057,https://api.github.com/repos/pydata/xarray/issues/4193,673978057,MDEyOklzc3VlQ29tbWVudDY3Mzk3ODA1Nw==,10194086,2020-08-14T09:15:15Z,2020-08-14T09:15:15Z,MEMBER,"> Overall, it feels a bi ugly because of the duplicated code

Looks fine to me.

> and it will print the warning for every line of an array that has a deficient rank, which can be a lot...

That could be annoying as a user. This happens in `results = da.apply_along_axis(nputils._nanpolyfit_1d, ...)`, right? Can you use a `warnings.simplefilter(""once"")` so the error is only issued once - something along the lines of:

```python
with warnings.catch_warnings():
    warnings.simplefilter(""once"", np.RankWarning)
    results = da.apply_along_axis(
        nputils._nanpolyfit_1d,
        ...
    )
```

I think this also warrants tests and a whats-new entry.


","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,650044968