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-482403368,https://api.github.com/repos/pydata/xarray/issues/2011,482403368,MDEyOklzc3VlQ29tbWVudDQ4MjQwMzM2OA==,1217238,2019-04-12T01:43:07Z,2019-04-12T01:43:07Z,MEMBER,"> * is `fill_value='periodic'` a good api?

`fill_value='periodic'` almost suggests padding with the string 'periodic'. Maybe `padding='periodic'` vs `padding=None` (default)?","{""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-482402058,https://api.github.com/repos/pydata/xarray/issues/2011,482402058,MDEyOklzc3VlQ29tbWVudDQ4MjQwMjA1OA==,1217238,2019-04-12T01:36:11Z,2019-04-12T01:36:11Z,MEMBER,"It might make sense to start with the higher level `pad()` with periodic boundary conditions first (https://github.com/pydata/xarray/issues/2605). Then rolling with periodic boundary conditions is a simple matter of padding, then rolling.","{""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-482143007,https://api.github.com/repos/pydata/xarray/issues/2011,482143007,MDEyOklzc3VlQ29tbWVudDQ4MjE0MzAwNw==,1197350,2019-04-11T14:41:23Z,2019-04-11T14:41:23Z,MEMBER,"Rather than letting this PR lie dormant, maybe we should just move forward without dask support and raise an appropriate error if the user tries it with dask arrays.","{""total_count"": 1, ""+1"": 1, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,308039063
https://github.com/pydata/xarray/pull/2011#issuecomment-392228821,https://api.github.com/repos/pydata/xarray/issues/2011,392228821,MDEyOklzc3VlQ29tbWVudDM5MjIyODgyMQ==,17162724,2018-05-26T02:22:07Z,2018-05-26T14:32:19Z,CONTRIBUTOR,"I may pick up this PR but will need some hand holding as i'm not familiar with dask.

I want to make sure I can do periodic rolling with dask in a simple script first but it needs work: https://gist.github.com/raybellwaves/621faaf195c0f4ed010b7b0dfee8605a","{""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-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-376122203,https://api.github.com/repos/pydata/xarray/issues/2011,376122203,MDEyOklzc3VlQ29tbWVudDM3NjEyMjIwMw==,10194086,2018-03-26T10:37:00Z,2018-03-26T10:37:00Z,MEMBER,"Thanks for the discussion. I could not get it to work with dask - the problem is the 'padding before ghosting'. 

https://github.com/pydata/xarray/blob/7c2c43ce6b1792e1193635ab9b64fd248266f632/xarray/core/dask_array_ops.py#L60-L62

I see no way how to get the `boundary='periodic'` working afterwards...","{""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
https://github.com/pydata/xarray/pull/2011#issuecomment-375677083,https://api.github.com/repos/pydata/xarray/issues/2011,375677083,MDEyOklzc3VlQ29tbWVudDM3NTY3NzA4Mw==,10194086,2018-03-23T14:10:08Z,2018-03-23T14:50:02Z,MEMBER,"We would probably have to test how `min_periods` and `periodic` play together..., see #2010 

---
edit: or not, as  `min_periods` is not used in `construct`
","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,308039063