Increase matrix size, with the first matrix a the center of the new matrix

Hi,

suppose to have a matrix (2000x2000) now i want to copy it in a bigger matrix (4000x4000 for example), with the original matrix at the center of the second matrix, and the other values set to 0. How can I do?

I have done it with for loop, but it is slow

Answer 1

[Turlough Hughes]

There is a function made specifically for this called padarray, try the following example:

A = rand(2000);
B = padarray(A,[1000 1000]);

[Alberto Paniate]

So if I have my matrix, A 2000x2000 and I create B=zeros(4000,4000) an I want to put at the center of B, I have to write C= padarray(A, [1000 100])?

[Turlough Hughes]

Creating an array B=zeros(4000) is unnecessary because you are not using it in the next step. You can simply write:

C = padarray(A,[1000 1000]);

to get what you are looking for.