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This script lives in /reg/g/psdmsdf/group/lcls/ds/ana/tutorials/examplePython3psana1_examples/mpiGather.py and demonstrates how to save small pieces of information on every event (in parallel) and then gather those pieces together onto one core.
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Run this
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with
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"mpirun
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-n
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2
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python
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mpiGather.py":
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from psana import *
import numpy as np
ds = DataSource('exp=xpptut15:run=54:smd')
det = Detector('cspad')
from mpi4py import MPI
comm = MPI.COMM_WORLD
rank = comm.Get_rank()
size = comm.Get_size()
intensity = []
for nevent,evt in enumerate(ds.events()):
if nevent%size!=rank: continue # different ranks look at different events
img = det.image(evt)
intensity.append(img.sum())
if nevent>=3: break
allIntensities = comm.gather(intensity) # get intensities from all ranks
if rank==0:
allIntensities = np.concatenate((allIntensities[:])) # put in one long list
print(allIntensities)
MPI.Finalize() |
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