bcolz/bench/getitem.py

# Benchmark for getitem

from time import time

import numpy as np

import bcolz
from bcolz.py2help import xrange


N = int(1e7)  # the number of elements in x
M = 100000  # the elements to get
clevel = 1  # the compression level

print("Creating inputs with %d elements..." % N)

cparams = bcolz.cparams(clevel)

# x = np.arange(N)
x = np.zeros(N, dtype="f8")
y = x.copy()
z = x.copy()
cx = bcolz.carray(x, cparams=cparams)
cy = cx.copy()
cz = cx.copy()
ct = bcolz.ctable((cx, cy, cz), names=['x', 'y', 'z'])
t = ct[:]

print("Starting benchmark now for getting %d elements..." % M)
# Retrieve from a ndarray
t0 = time()
vals = [x[i] for i in xrange(0, M, 3)]
print("Time for array--> %.3f" % (time() - t0,))
print("vals-->", len(vals))

#bcolz.set_num_threads(bcolz.ncores//2)

# Retrieve from a carray
t0 = time()
cvals = [cx[i] for i in xrange(0, M, 3)]
#cvals = cx[:M:3][:].tolist()
print("Time for carray--> %.3f" % (time() - t0,))
print("vals-->", len(cvals))
assert vals == cvals

# Retrieve from a structured ndarray
t0 = time()
vals = [t[i] for i in xrange(0, M, 3)]
print("Time for structured array--> %.3f" % (time() - t0,))
print("vals-->", len(vals))

# Retrieve from a ctable
t0 = time()
cvals = [ct[i] for i in xrange(0, M, 3)]
#cvals = ct[:M:3][:].tolist()
print("Time for ctable--> %.3f" % (time() - t0,))
print("vals-->", len(cvals))
assert vals == cvals