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########################################################################
#
# License: MIT
# Created: Jan 19, 2013
# Author: Francesc Alted - faltet@gmail.com
#
########################################################################
"""
Small benchmark that compares a plain NumPy array copy against
compression through different compressors in Blosc.
"""
from __future__ import print_function
import numpy as np
import time
import blosc
import ctypes
N = int(1e8)
clevel = 5
Nexp = np.log10(N)
blosc.print_versions()
print("Creating NumPy arrays with 10**%d int64/float64 elements:" % Nexp)
arrays = ((np.arange(N, dtype=np.int64), "the arange linear distribution"),
(np.linspace(0, 1000, N), "the linspace linear distribution"),
(np.random.randint(0, 1000 + 1, N), "the random distribution")
)
in_ = arrays[0][0]
# cause page faults here
out_ = np.full(in_.size, fill_value=0, dtype=in_.dtype)
t0 = time.time()
#out_ = np.copy(in_)
out_ = ctypes.memmove(out_.__array_interface__['data'][0],
in_.__array_interface__['data'][0], N*8)
tcpy = time.time() - t0
print(" *** ctypes.memmove() *** Time for memcpy():\t%.3f s\t(%.2f GB/s)" % (
tcpy, (N*8 / tcpy) / 2**30))
print("\nTimes for compressing/decompressing with clevel=%d and %d threads" % (
clevel, blosc.nthreads))
for (in_, label) in arrays:
print("\n*** %s ***" % label)
for cname in blosc.compressor_list():
for filter in [blosc.NOSHUFFLE, blosc.SHUFFLE, blosc.BITSHUFFLE]:
t0 = time.time()
c = blosc.compress_ptr(in_.__array_interface__['data'][0],
in_.size, in_.dtype.itemsize,
clevel=clevel, shuffle=filter, cname=cname)
tc = time.time() - t0
# cause page faults here
out = np.full(in_.size, fill_value=0, dtype=in_.dtype)
t0 = time.time()
blosc.decompress_ptr(c, out.__array_interface__['data'][0])
td = time.time() - t0
assert((in_ == out).all())
print(" *** %-8s, %-10s *** %6.3f s (%.2f GB/s) / %5.3f s (%.2f GB/s)" % (
cname, blosc.filters[filter], tc, ((N*8 / tc) / 2**30), td, ((N*8 / td) / 2**30)), end='')
print("\tCompr. ratio: %5.1fx" % (N*8. / len(c)))
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