为什么 Y*=2
比 Y+=Y
快?
elepased = timeit.timeit(
stmt="Y*=2; np.add(X, Y, out=X)",
setup=setup,
number=iterations
)
elepased / iterations * 1e6
81.25868347997312
elepased = timeit.timeit(
stmt="Y+=Y; np.add(X, Y, out=X)",
setup=setup,
number=iterations
)
elepased / iterations * 1e6
92.05061321998073
import numpy as np
import timeit
setup = """
import numpy as np
X = np.ones(100000, dtype=np.int)
Y = np.ones(100000, dtype=np.int)
"""
iterations = 100000