问Python与Matlab的循环性能比较

EN

import numpy as np
import time

N = 10000000

a = np.random.random(N)
b = np.random.random(N)

#vectorized
start_time = time.time()
c = np.dot(a,b)
print(c)
print("--- %s msec ---" % (time.time() - start_time))

#non-vectorized
start_time = time.time()
c = 0
for ii in range(N):
    c = c + a[ii]*b[ii]
print(c)
print("--- %s msec ---" % (time.time() - start_time))

N = 10000000;

a = rand(N, 1);
b = rand(N, 1);

tic
c = dot(a, b);
disp(c);
toc

tic
c = 0;
for ii = 1:N
 c = c + a(ii) * b(ii);
end
disp(c)
toc

2500596.6897313246
--- 0.008107662200927734 sec ---
2500596.689731018
--- 3.6871590614318848 sec ---

2.4997e+06
Elapsed time is 0.027503 seconds.

2.4997+06
Elapsed time is 0.032014 seconds.