On 06/02/18 12:09, Leonardo Hardtke wrote:
Dear all,
I am working on a module to extract the phenological parameters (like
timesat) from a time series implemented in python/cython and making use
of gscript and other grass stuff.
It works great on a 256x256 and as the plan is applying it over
Australia at 250m over 17 years, I need to split the process in small
tiles. The idea is to run this processes in parallel and I am having
issues implementing it.
This would be the first part of the process that runs on each tile:
def tile_process(tile_index):
'''
Function for every worker:
Applies any function to the sub_region corresponding to the tile_index.
'''
global Rows
global Cols
global RowBlockSize
global ColBlockSize
global full_region
global dates
global years
global indices
global data_serie
global yr_limits_extra
global yr_limits
global dbif
sub_name='block'
TileRow, TileCol, sr =
sub_region(tile_index,full_region,RowBlockSize,ColBlockSize)
# # Define a temporary region based on the parameters caluculated
with the
start_row = TileRow * RowBlockSize
start_col = TileCol * ColBlockSize
n_rows = sr['rows']
n_cols = sr['cols']
strds = tgis.SpaceTimeRasterDataset(data_serie)
strds.select(dbif=dbif)
maps = strds.get_registered_maps_as_objects(dbif=dbif)
# Numer of time steps
steps = len(maps)
# Make an empty array
#print(steps)
EVI = np.empty([steps,n_rows,n_cols])
# fill the array
for step, map in enumerate(maps):
map.select(dbif=dbif)
image_name = map.get_name()+'@'+data_serie.split('@')[1]
#print("reading: {}".format(image_name))
EVI[step,:] =
raster2numpy_sub(image_name,start_row,n_rows,start_col,n_cols)
mean = EVI.mean()
print(mean)
....
....
....
and this is how I start the multiprocess pool.
pool.map(tile_process, xrange(RowBlockN*ColBlockN))
pool.close()
pool.join()
and it gives me:
AssertionError: can only test a child process
of course if I do: tile_process(0) or tile_process(1) etc ,the right
result comes out.
Does any of you have experience with this? Any suggestion would be welcome!
Sorry for the messy code. Is still in early stage.
Just a wild guess: have you tried with range (which returns a list)
instead of xrange (which returns an xrange object) ?
Moritz
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