レシピ4.5
import numpy as np
def id(x):
return x.__array_interface__['data'][0]
a=np.array([1,2,3,4,5,6,7,8,9,10])
print(id(a))
print(id(a[1:]))
out[]
66570080 66570084
4*8bit=32bit
import numpy as np
a = np.random.rand(5000,5000)
%timeit a[0,:] .sum()
%timeit a[:,0] .sum()
The slowest run took 13.13 times longer than the fastest. This could mean that an intermediate result is being cached 100000 loops, best of 3: 3.17 µs per loop 10000 loops, best of 3: 53.8 µs per loop
レシピ4.6
x = np.zeros(10)
print(x.strides)
y = np.zeros*1
print(y.strides)
積読:
統計処理ポケットリファレンス
*1:10,10