MATLAB: Extract a sub-matrix from a very big matrix

indexingmatrixmatrix manipulationseparation

I have a matrix of size 112 x 1200. I want to separate them into 6 matrices each of size 112 x 200. How can i do it?

reshape(a,[],200,6)

You can't chain indexing operations, so you can either create a temporary variable

subarr = arr(i:i+n-1, j:j+n-1);
x = somefn(subarr(:), a);

Or, since the colon here just does a reshape, call reshape explicitly:

x = somefn(reshape(arr(i:i+n-1, j:j+n-1), [], 1), a);

reshape(A,512,[],243)