How to split a 3d matrix into sub-3d matrices?

How can I split e.g. a a1xb1xc matrix into non-overlapping (neighbouring) smaller matrices a2xb2xc?

[Stephen23]

https://www.mathworks.com/help/matlab/ref/mat2cell.html

https://www.mathworks.com/help/matlab/ref/num2cell.html

Answer 1

[Bruno Luong]

probably you can use

mat2cell

IMO splitting a matrix in cell is rarely a good idea if you want your code works decenly in speed.

Answer 2

[Constantino Carlos Reyes-Aldasoro]

There is not enough information to be certain about your question, but by addressing your matrices you can create submatrices like this:

BigMatrix     = ones(16,16,16);
smallMatrix_1 = BigMatrix(1:8,1:8,1:8);
smallMatrix_2 = BigMatrix(1:8,1:8,9:16);
smallMatrix_3 = BigMatrix(1:8,9:16,1:8);
smallMatrix_4 = BigMatrix(9:16,1:8,1:8);

etc.

[madhan ravi]

What if the numel(matrix) is 16e3 ?

[Constantino Carlos Reyes-Aldasoro]

Ok that is big, but rather that numel try using size:

[rows,columns,levels]= size(BigMatrix);

Then you know the size of each dimension. You can then iterate over each by partitioning them, e.g.

subrows    = linspace (1,rows,numSections);
subcolumns = linspace (1,columns,numSections);
sublevels  = linspace (1,levels,numSections);

so that you then iterate over each section of the rows, columns and levels.

Hope this helps

[madhan ravi]

Ok, thanks;)

[Constantino Carlos Reyes-Aldasoro]

Glad to help! If this solves the question, could you please accept the answer?

[madhan ravi]

I’m not the original poster, sorry :(

[Constantino Carlos Reyes-Aldasoro]

of course!