在Matlab中创建此矩阵 [英] creating this matrix in matlab

问题描述

给出

A=[a_1 a_2 a_3 ... a_n]

如何制作?

[a1 ... a100]
[a2 ... a101]
...
[an-100+1 ... an]

我不想在这里使用for循环，因为我想加快速度. 谢谢.

I want to not use for-loop here since I want to speed it up. Thank you.

推荐答案

您可以使用:

n = numel(A);
m = 100;
I = bsxfun(@plus, 1:m, (0:n-m).');
B = A(I);

作为旁注:for循环执行的那不好:

As a sidenote: The for loop doesn't perform that bad:

B = zeros(n-m+1, m);
for i = 1:size(B)
    B(i,:) = A(i:i+m-1);
end

就我的测试而言，它仅慢4倍，而且无论如何，此计算都几乎不会成为您程序中的瓶颈.

As far as my testing goes, it is slower only by a factor of 4 and this calculation should hardly be a bottleneck in your program anyway.

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