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/2011#issuecomment-376145446,https://api.github.com/repos/pydata/xarray/issues/2011,376145446,MDEyOklzc3VlQ29tbWVudDM3NjE0NTQ0Ng==,6815844,2018-03-26T12:16:12Z,2018-03-26T12:16:12Z,MEMBER,"Ah, you are right. The only way to realize rolling.periodic with dask would be to manually attach a chunk in the other side to the boundaries, construct rolling window array and then remove unnecessary boundaries by slicing. ","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,308039063 https://github.com/pydata/xarray/pull/2011#issuecomment-375835173,https://api.github.com/repos/pydata/xarray/issues/2011,375835173,MDEyOklzc3VlQ29tbWVudDM3NTgzNTE3Mw==,6815844,2018-03-24T01:07:32Z,2018-03-24T01:07:32Z,MEMBER,"Some comments. + We need to also support a dask array. Can you update `dask_array_op.rolling_window`? Maybe [this page](http://dask.pydata.org/en/latest/array-ghost.html#boundaries) would help for the implementation. We use this here https://github.com/pydata/xarray/blob/7c2c43ce6b1792e1193635ab9b64fd248266f632/xarray/core/dask_array_ops.py#L78-L79 I suspect this would be already working, but it would be nice if we can add some test cases. + Maybe we can also add `boundary='reflect'` option to make this as similar to `dask.ghost`.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,308039063 https://github.com/pydata/xarray/pull/2011#issuecomment-375833339,https://api.github.com/repos/pydata/xarray/issues/2011,375833339,MDEyOklzc3VlQ29tbWVudDM3NTgzMzMzOQ==,6815844,2018-03-24T00:45:25Z,2018-03-24T01:03:50Z,MEMBER,"Thanks for sending a PR. > is fill_value='periodic' a good api? Maybe better API would be `boundary='peiodic'` (see [comments](https://github.com/pydata/xarray/issues/2007#issuecomment-375828864)), but changing the public API is not an easy task. Let's keep it now as is and decide it later. > should the fill_value keyvalue be ported to rolling? I don't think so. I think we can keep rolling as similar to that of pandas, and this option should be specific to `construct` method. > should this also be mentioned in the docs for rolling (I only learned about rolling.construct yesterday) I think at least we need to add this to the docstring of `construct`.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,308039063