# How to find every principal submatrix of a matrix. (given input row and column indices)

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I am curious as to find out how I can write so that given a square matrix, the program can compute "every" principal submatrix of the matrix.

I know how to find the basic ones; for example, given a 5x5 square matrix, finding principal submatrix by deleting same row and column. But I am struggling to find a principal matrix of let's say deleting 1st and 3rd row and column and etc.

How can I write this into a matlab code?

Thanks for any tips in advance!

##### 2 Comments

Steven Lord
on 21 May 2023

### Answers (1)

KSSV
on 21 May 2023

You can delete 1, 3 rd row and column from 5x5 matrix using:

A = rand(5) ;

A([1 3],:) = [] ; % delete 1st and 3rd row

A(:,[1 3]) = [] ; % delete 1st and 3rd column

##### 3 Comments

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