How to split a matrix in "submatrices"?

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Francesco Boari
Francesco Boari le 12 Déc 2017
Commenté : Francesco Boari le 13 Déc 2017
How can i divide a matrix into submatrices of given dimensions in automatic way?
example:
data=reshape(1:88,11,8); %create a matrix
[mpixel,npixel]=size(data); %matrix's dimensions
m=2; %rows of the submatrix
n=3; %columns of the submatrix
v_w=floor(mpixel/m); %number of "vertical" submatrices
h_w=floor(npixel/n); %number of "horizontal" submatrices
cropdata=data(1:v_w*m,1:h_w*n);%crop matrix that can be diveded using that mxn submatrices
%
newdata=mat2cell(cropdata,[m m m m m],[n n]);
This code work but if I have bigger matrix I must continue to explicit [m m m...],[n n n...] in the last command and it's crazy. How can i use the command mat2cell with a smarter way?
  4 commentaires
Image Analyst
Image Analyst le 12 Déc 2017
Why not just use blockproc() and let that handle the getting of the submatrices?
Francesco Boari
Francesco Boari le 13 Déc 2017
I see the documentation of blockproc(), it processes block by block but at the end the output it's the input image/matrix.

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Guillaume
Guillaume le 13 Déc 2017
As others have said, there may be no need to explicitly split the matrix, but if you must what is wrong with:
newdata = mat2cell(cropdata, repelem(m, v_w), repelem(n, h_w));
  1 commentaire
Francesco Boari
Francesco Boari le 13 Déc 2017
Thanks! It works. Meanwhile i have found a different way leaving, as someone said, the original matrix and indexing.

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