python_performance/array_access_patterns.py at main · rafmudaf/python_performance · GitHub

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importgc
importnumpyasnp
importtime

# contiguous_array[i-1]
# contiguous_array[i]
# contiguous_array[i+1]
# new_array1 = np.ones(np.shape(contiguous_array))

print("Configuration")
# Python float is 64 bit / 8 byte
ARRAY_SIZE=1000*1000*1
print("- Size of data array: {} MB".format(ARRAY_SIZE*8/ (1000*1000)))

N=10
print("- Number of iterations to average: {}".format(N))

defSETUP():
array1=np.ones(ARRAY_SIZE)
array2=np.ones(ARRAY_SIZE)
buffer_array=np.empty(ARRAY_SIZE)
returnarray1, array2, buffer_array


if__name__=="__main__":
# gc.disable()

print("{:45}{:<15}{:<15}".format("Case description", "Total time", "Per-iteration time"))

array1, array2, buffer_array=SETUP()
index_map=np.random.randint(0, ARRAY_SIZE-1, size=ARRAY_SIZE)
elapsed_time=0.0
for_inrange(N):
start=time.time()

foriinindex_map:
buffer_array[i] =array1[i] +array2[i]

end=time.time()
elapsed_time+=end-start
average=elapsed_time/N
print("{:45}{:<15.6f}{:<15.6f}".format("Non-contiguous access, no vectorization", elapsed_time, average))


array1, array2, buffer_array=SETUP()
elapsed_time=0.0
for_inrange(N):
start=time.time()

foriinrange(ARRAY_SIZE):
buffer_array[i] =array1[i] +array2[i]

end=time.time()
elapsed_time+=end-start
average=elapsed_time/N
print("{:45}{:<15.6f}{:<15.6f}".format("Contiguous access, no vectorization", elapsed_time, average))


array1, array2, buffer_array=SETUP()
index_map=np.random.randint(0, ARRAY_SIZE-1, size=ARRAY_SIZE)
elapsed_time=0.0
for_inrange(N):
start=time.time()

buffer_array=array1[index_map] +array2[index_map]

end=time.time()
elapsed_time+=end-start
average=elapsed_time/N
print("{:45}{:<15.6f}{:<15.6f}".format("Non-contiguous access, vectorization", elapsed_time, average))


array1, array2, buffer_array=SETUP()
index_map=np.arange(0, ARRAY_SIZE)
elapsed_time=0.0
for_inrange(N):
start=time.time()

buffer_array=array1[index_map] +array2[index_map]

end=time.time()
elapsed_time+=end-start
average=elapsed_time/N
print("{:45}{:<15.6f}{:<15.6f}".format("Contiguous access, vectorization", elapsed_time, average))


array1, array2, buffer_array=SETUP()
elapsed_time=0.0
for_inrange(N):
start=time.time()

buffer_array=array1+array2

end=time.time()
elapsed_time+=end-start
average=elapsed_time/N
print("{:45}{:<15.6f}{:<15.6f}".format("Numpy arithmetic", elapsed_time, average))