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/1224#issuecomment-519833424,https://api.github.com/repos/pydata/xarray/issues/1224,519833424,MDEyOklzc3VlQ29tbWVudDUxOTgzMzQyNA==,6213168,2019-08-09T08:36:09Z,2019-08-09T08:36:09Z,MEMBER,Retiring this as it is way too specialized for the main xarray library.,"{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,202423683
https://github.com/pydata/xarray/issues/1224#issuecomment-388545372,https://api.github.com/repos/pydata/xarray/issues/1224,388545372,MDEyOklzc3VlQ29tbWVudDM4ODU0NTM3Mg==,6213168,2018-05-12T10:22:02Z,2018-05-12T10:22:02Z,MEMBER,"Both. One of the biggest problem is that the data of my interestest is a mix of
- 1D arrays with dims=(scenario, ) and shape=(500000, ) (stressed financial instruments under a Monte Carlo stress set)
- 0D arrays with dims=() (financial instruments that are impervious to the Monte Carlo stresses and never change values)
So before you do concat(), you need to call broadcast(), which effectively means that doing the sums on your bunch of very fast 0D instruments suddendly requires repeating them on 500k points.

Even keeping the two lots separate (which is fastwsum does) performed considerably slower.

However, this was over a year ago and much before xarray.dot() and dask.einsum(), so I'll need to tinker with it again.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,202423683
https://github.com/pydata/xarray/issues/1224#issuecomment-274380448,https://api.github.com/repos/pydata/xarray/issues/1224,274380448,MDEyOklzc3VlQ29tbWVudDI3NDM4MDQ0OA==,6213168,2017-01-23T02:02:08Z,2017-01-23T02:02:08Z,MEMBER,"``(arrays * weights).sum('stacked')`` was my first attempt. It performed considerably worse than ``sum(a * w for a, w in zip(arrays, weights))`` - mostly because xarray.concat() is not terribly performant (I did not look deeper into it).

I did not try dask.array.sum() - worth some playing with.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,202423683