矩阵相乘的for循环中的错误

Question

以下代码在else语句上失败，出现以下错误：

File "C:\Users\feder\Anaconda3\lib\site-packages\numpy\matrixlib\defmatrix.py", line 195, in __getitem__ out = N.ndarray.__getitem__(self, index)

IndexError: index 117 is out of bounds for axis 1 with size 1

for i in range(0, int(N / 2)):
    if i == 0:
        x[:, 0] = C * xvec_tra
        print(x[:, 0])
    else:
        x[:, i] = C * x[:, i-1] # C is matrix 4x4 and xvec_tra is a matrix 4x1
        print(x[:, i])

我怎样才能修好它