如何加快嵌套循环？ Python

Question

def model_predykycjny(r):
    macierz_R = np.zeros((r, r))
    for i in range(1, r + 1):
        for j in range(1, r + 1):
            suma_iloczynow = 0
            if i <= j:

I want to speed up this loop

                for n in range(r, len(fixed_data_channel0)):
                    suma_iloczynow += float(fixed_data_channel0[n - i]) * float(fixed_data_channel0[n - j])
                macierz_R[i - 1][j - 1] = (np.float(suma_iloczynow))
            suma_iloczynow = 0

time for r =3: 7.9424097537994385

Answer 1

You might use range s so you would need not to check i<=j , consider that

r = 3
for i in range(1, r+1):
    for j in range(1, r+1):
        if i<=j:
            print(i,j)

is equivalent to

r = 3
for i in range(1, r+1):
    for j in range(i, r+1):
        print(i,j)