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/4085#issuecomment-631670146,https://api.github.com/repos/pydata/xarray/issues/4085,631670146,MDEyOklzc3VlQ29tbWVudDYzMTY3MDE0Ng==,2599958,2020-05-20T19:11:56Z,2020-05-20T19:11:56Z,NONE,"The problem was only with very large arrays, so difficult to reproduce here. Fortunately, when I just now updated to the very latest xarray/dask, the problem seems to have gone away. I was puzzled because things worked fine -- as expected -- but only for smaller arrays. I will close this issue.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,621968474 https://github.com/pydata/xarray/issues/4085#issuecomment-631658737,https://api.github.com/repos/pydata/xarray/issues/4085,631658737,MDEyOklzc3VlQ29tbWVudDYzMTY1ODczNw==,2448579,2020-05-20T18:50:50Z,2020-05-20T18:50:50Z,MEMBER,Something is very wrong here. is this reproducible?,"{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,621968474 https://github.com/pydata/xarray/issues/4085#issuecomment-631636660,https://api.github.com/repos/pydata/xarray/issues/4085,631636660,MDEyOklzc3VlQ29tbWVudDYzMTYzNjY2MA==,34353851,2020-05-20T18:07:22Z,2020-05-20T18:07:22Z,NONE,"I use http://xarray.pydata.org/en/stable/generated/xarray.apply_ufunc.html because it is faster. El mié., 20 may. 2020 a las 20:01, Javier Ruano () escribió: > if you append compute() it should not be a lazy operation. > But my advice is like user only. > > El mié., 20 may. 2020 a las 19:51, Rob Hetland () > escribió: > >> I have a large DataSet, including these DataArrays: >> >> >> dask.array >> >> and >> >> >> dask.array >> >> (The coordinates and attributes excluded for brevity, but they match in >> the right ways.) >> >> When I do math operations with the 4D DataArray (temp) and 3D DataArray >> (zeta), no problem: >> >> ds.zeta * ds.temp >> >> >> dask.array >> >> This returns an object instantly, and the result is lazily evaluated. >> However, if I just try to add temp to itself, >> >> ds.temp + ds.temp >> >> this fails (eventually) as my medium sized computer runs out of memory, >> since it starts to evaluate the numbers as if I did a compute() or asked >> for the values. Note 2*ds.temp or ds.temp**2 is lazily evaluated, and >> returns an object instantly. Chunk size does not seem to be an issue, as I >> have tried a number of reasonable choices without success. >> >> Why can't such simple math operations between two large arrays also be >> lazily evaluated? >> >> — >> You are receiving this because you are subscribed to this thread. >> Reply to this email directly, view it on GitHub >> , or unsubscribe >> >> . >> > ","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,621968474 https://github.com/pydata/xarray/issues/4085#issuecomment-631633988,https://api.github.com/repos/pydata/xarray/issues/4085,631633988,MDEyOklzc3VlQ29tbWVudDYzMTYzMzk4OA==,34353851,2020-05-20T18:01:42Z,2020-05-20T18:01:42Z,NONE,"if you append compute() it should not be a lazy operation. But my advice is like user only. El mié., 20 may. 2020 a las 19:51, Rob Hetland () escribió: > I have a large DataSet, including these DataArrays: > > > dask.array > > and > > > dask.array > > (The coordinates and attributes excluded for brevity, but they match in > the right ways.) > > When I do math operations with the 4D DataArray (temp) and 3D DataArray > (zeta), no problem: > > ds.zeta * ds.temp > > > dask.array > > This returns an object instantly, and the result is lazily evaluated. > However, if I just try to add temp to itself, > > ds.temp + ds.temp > > this fails (eventually) as my medium sized computer runs out of memory, > since it starts to evaluate the numbers as if I did a compute() or asked > for the values. Note 2*ds.temp or ds.temp**2 is lazily evaluated, and > returns an object instantly. Chunk size does not seem to be an issue, as I > have tried a number of reasonable choices without success. > > Why can't such simple math operations between two large arrays also be > lazily evaluated? > > — > You are receiving this because you are subscribed to this thread. > Reply to this email directly, view it on GitHub > , or unsubscribe > > . > ","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,621968474