issues: 280942467

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id node_id number title user state locked assignee milestone comments created_at updated_at closed_at author_association active_lock_reason draft pull_request body reactions performed_via_github_app state_reason repo type
280942467 MDU6SXNzdWUyODA5NDI0Njc= 1774 xarray mean generates unstable dask name (hash) 27647769 closed 0     2 2017-12-11T09:11:31Z 2017-12-11T20:43:35Z 2017-12-11T20:43:35Z NONE      

Code Sample

```python import dask.array as da import xarray as xr import numpy as np

create dask array

x = da.ones((5, 5), chunks=(2, 2))

create xarray array

x2 = xr.DataArray(x, dims=['d1', 'd2'])

print dask name after taking mean

x = x.mean(axis=0) print(x.name)

print dask name after taking mean

x2 = x2.mean(dim='d1') print(x2.data.name)

confirm both functions do the same

print(np.allclose(x.compute(), x2.data.compute())) ```

Problem Description

Running the above sample three times outputs: ``` mean_agg-aggregate-9716da6e38d695dbff18f713d787e614 mean_agg-aggregate-02c33c19e6209edbe409749388d2f9f0 True

mean_agg-aggregate-9716da6e38d695dbff18f713d787e614 mean_agg-aggregate-2f59be8ef8c35336717fdcd7744bd167 True

mean_agg-aggregate-9716da6e38d695dbff18f713d787e614 mean_agg-aggregate-822994428d6b4cdea8e5c134711e5609 True ``` which shows the dask name (hash) generated using the xarray mean is unstable.

Expected Output

For processing large datasets, it's convenient to have a stable hash name in order to save intermediate results or compare them among developers.

Current workaround: unwrap dask array and recreate xarray array.

Output of xr.show_versions()

INSTALLED VERSIONS ------------------ commit: None python: 3.5.2.final.0 python-bits: 64 OS: Linux OS-release: 4.8.0-58-generic machine: x86_64 processor: x86_64 byteorder: little LC_ALL: None LANG: en_US.UTF-8 LOCALE: en_US.UTF-8 xarray: 0.10.0 pandas: 0.21.0 numpy: 1.13.3 scipy: 0.19.1 netCDF4: None h5netcdf: None Nio: None bottleneck: None cyordereddict: None dask: 0.16.0 matplotlib: 2.1.0 cartopy: None seaborn: None setuptools: 38.2.3 pip: 9.0.1 conda: None pytest: None IPython: 6.2.1 sphinx: None 
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   completed 13221727 issue

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