extract non-zeros block from matrice

I have a matrix that contains several non-zeros blocks.The rest of the elements are zero. I want to put each of these blocks in a separate matrix. how can i do it?

Answer 1

[jonas]

Not sure exactly what you want to do. The following creates a vector B containing all non-zeros of A

B=A(A~=0)

Do you want to extract several small matrices from a larger global matrix?

[khatere darvish]

dear jonas yes,i want to extract small matrices from a largger global matrix. for example i want to extract the small matrices are shown in the figure

[khatere darvish]

[jonas]

If you already know the indices of your blocks, then you can simply extract them by:

a1=A(row1:row2,col1:col2);

In your example: a1=A(1:2,1:3); a2=A(1:3,6:7);

Or do you need a more general function for extracting any rectangular-sized block?

EDIT: The image processing toolbox has a function called bwconncomp() that will find connecting non-zero values (BLOCKS) and output their indices. It should work as long as the blocks are completely separated by zeros.

[Jan]

Do you have the image processing toolbox?

[khatere darvish]

yes i have it. thank you so much for your help