[yt-dev] embarrassingly parallel analysis

[Geoffrey So]

Hi all, I was trying out pobj_demo.py from the workshop to see if I can
parallelize my halo analysis script, but I ran into the problem where I see:

>mpirun -n 2 python pobj_demo.py --parallel

gives a warning at the end

yt : [WARNING  ] 2012-03-16 16:25:05,445 parallel_objects() is being used
when parallel_capable is false. The loop is not being run in parallel. This
may not be what was expected.

I've done a
yt instinfo -u and got the latest tip:

052fac826701 (yt) tip

but the problem persists.  I've tried printing inside the parallel loops

for sto, sp in parallel_objects(spheres, num_procs, storage = my_storage):
    print ytcfg.getint("yt", "__global_parallel_rank")
    sto.result = sp.quantities['TotalQuantity']('CellMass')
    sto.result_id = '%4e %4e %4e' % (sp.center[0],
sp.center[1],sp.center[2])

and I always get "0", but 20 of them, so I'm guessing that confirms the
loop isn't running in parallel, and just runs the 10 spheres serially on 2
processors, so I get double the results.

Am I doing something wrong or missed something?

From
G.S.
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