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/2113#issuecomment-388509895,https://api.github.com/repos/pydata/xarray/issues/2113,388509895,MDEyOklzc3VlQ29tbWVudDM4ODUwOTg5NQ==,6815844,2018-05-11T23:27:22Z,2018-05-12T00:25:25Z,MEMBER,"~I noticed that this bug arises when bottleneck is installed.~

EDIT
The test suite was not checking `center=True`. I will look inside the code.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,321917084
https://github.com/pydata/xarray/issues/2113#issuecomment-388489805,https://api.github.com/repos/pydata/xarray/issues/2113,388489805,MDEyOklzc3VlQ29tbWVudDM4ODQ4OTgwNQ==,17162724,2018-05-11T21:25:32Z,2018-05-11T21:25:50Z,CONTRIBUTOR,"I realized there with an issue before that in without `center=True` it doesn't raise an issue but it returns rubbish:

```
import xarray as xr
import numpy as np

a = xr.DataArray(np.arange(1,4), coords=[np.arange(1,4)], dims='x')
print(a.rolling(x=3, center=True).mean())
Out[2]: 
<xarray.DataArray (x: 3)>
array([ nan,   2.,  nan])
Coordinates:
  * x        (x) int64 1 2 3
print(a.chunk().rolling(x=3).mean().values)
Out[3]: array([ -6.14891469e+18,  -9.22337204e+18,  -1.22978294e+19])
```

The culprit lies in a dask function https://github.com/pydata/xarray/blob/6d8ac11ca0a785a6fe176eeca9b735c321a35527/xarray/core/dask_array_ops.py#L24

Not sure if this is an issue with the function or the way the data is going into the function.

For the `center=True` issue: https://github.com/pydata/xarray/blob/6d8ac11ca0a785a6fe176eeca9b735c321a35527/xarray/core/rolling.py#L308
is slicing the data.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,321917084
https://github.com/pydata/xarray/issues/2113#issuecomment-388099066,https://api.github.com/repos/pydata/xarray/issues/2113,388099066,MDEyOklzc3VlQ29tbWVudDM4ODA5OTA2Ng==,1217238,2018-05-10T16:00:12Z,2018-05-10T16:00:12Z,MEMBER,"@raybellwaves thanks for the bug report!

Here's a slightly simplified version that shows the issue for dask:
```
import pandas as pd
import xarray as xr
import numpy as np

da_day_clim = xr.DataArray(np.arange(1, 367), coords=[np.arange(1, 367)], dims='dayofyear')
print(da_day_clim.rolling(dayofyear=31, center=True).mean())  # works
print(da_day_clim.chunk().rolling(dayofyear=31, center=True).mean())  # raises ValueError
```

The traceback is probably the place to start looking into this. I like to drop into a Python debugger (type `%debug` after the line that raised the error), navigate to different levels in the traceback with `u`/`d`, and then print out variables until I can identify which specific function/block of code seems to be doing the wrong thing.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,321917084
https://github.com/pydata/xarray/issues/2113#issuecomment-388042273,https://api.github.com/repos/pydata/xarray/issues/2113,388042273,MDEyOklzc3VlQ29tbWVudDM4ODA0MjI3Mw==,17162724,2018-05-10T12:43:18Z,2018-05-10T12:43:18Z,CONTRIBUTOR,Probably isn't a good first issue but I wouldn't like to spend some time on this. Welcome to suggest places to look and things to try.,"{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,321917084