Re: [gdal-dev] Parllelization slows down single gdal_calc process in python

2016-03-03 Thread Jerl Simpson
Hi Lorenzo: This is more of a question for the python community. However, a couple things I have noticed. Pandas tends to be much slower than working in numpy directly. I never saw an improvement in timings when using Pool(). What I do is utilize Process() and Queue() or JoinableQueue() from th

Re: [gdal-dev] Parllelization slows down single gdal_calc process in python

2016-03-03 Thread Kor de Jong
Dear Lorenzo, On 03/03/2016 12:13 PM, Lorenzo Bottaccioli wrote: Yes I have 8 cores! The I/O output files are different for each process. I have to preform the gdal_calc on different maps each process. I just wanted to lunch more than one gdal_calc.py script at time. Yes, I assumed the files u

Re: [gdal-dev] Parllelization slows down single gdal_calc process in python

2016-03-03 Thread Lorenzo Bottaccioli
Dear Kor, Yes I have 8 cores! The I/O output files are different for each process. I have to preform the gdal_calc on different maps each process. I just wanted to lunch more than one gdal_calc.py script at time. Best Lorenzo 2016-03-03 11:34 GMT+01:00 Kor de Jong : > Dear Lorenzo, > > On 03/0

Re: [gdal-dev] Parllelization slows down single gdal_calc process in python

2016-03-03 Thread Kor de Jong
Dear Lorenzo, On 03/03/2016 12:44 AM, Lorenzo Bottaccioli wrote: If i run the code with out parallelization it takes around 650s to complete the calculation. Each process of the for loop is executed in ~10s. If i run with parallelization it takes ~900s to complete the procces and each process of

Re: [gdal-dev] Parllelization slows down single gdal_calc process in python

2016-03-02 Thread Flippmoke
On my phone so can explain fully, but there are several blockers in GDAL Library that prevent multi threading from being effective. Try using different processes if it is completely required. Blake Thompson > On Mar 2, 2016, at 5:44 PM, Lorenzo Bottaccioli > wrote: > > Hi, > I'm trying to pa

[gdal-dev] Parllelization slows down single gdal_calc process in python

2016-03-02 Thread Lorenzo Bottaccioli
Hi, I'm trying to parallelize a code for raster calculation with Gdal_calc.py, but i have relay bad results. I need to perform several raster operation like FILE_out=FILA_a*k1+FILE_b*k2. This is the code I'm usign: import pandas as pdimport osimport timefrom multiprocessing import Pool df = pd.r