[yt-dev] Issue #944: Slices of fields that need ghost zones are slow for patch AMR data (yt_analysis/yt)

[Nathan Goldbaum]

New issue 944: Slices of fields that need ghost zones are slow for patch AMR data
https://bitbucket.org/yt_analysis/yt/issue/944/slices-of-fields-that-need-ghost-zones-are

Nathan Goldbaum:

On my laptop, the following script:


```
#!python

import yt
import time

def test(field):
    slc = yt.SlicePlot(ds, 2, field)

if __name__ == "__main__":
    ds = yt.load("GasSloshing/sloshing_nomag2_hdf5_plt_cnt_0150")
    ds.periodicity = (True, True, True)

    setup = "from __main__ import test"

    t0 = time.time()
    test('density')
    tden = time.time() - t0

    t0 = time.time()
    test('velocity_divergence')
    tdiv = time.time() - t0

    print tden, tdiv
```

shows that it takes about 3.5 seconds to do the density slice and 63 seconds to do the velocity_divergence slice.