I am trying to solve the inverse of a matrix A, using the equation AX=I and LU factorization. My lufact function worked originally, but when using to compute the inverse, A and X both end up as identity matrices.

I am trying to solve the inverse of a matrix A, using the equation AX=I and LU factorization. My lufact function worked originally, but when using to compute the inverse, A and X both end up as identity matrices.

function [A, X] = lufact(I)

% LUFACT LU factorization

% Gaussian elimination

for j = 1:n-1

for i = j+1:n

A(i,j) = I(i,j) / I(j,j); % row multiplier

I(i,:) = I(i,:) - A(i,j)*I(j,:);

end

end

X = rand(n,n);

end

[darova]

You don't check if your multipliear is inf (I(j,j) == 0) ?

[Athul Prakash]

Not sure that I follow your approach..

You want to find X such that AX=I, but when you factorize I, won't it produce any 2 factors which multiply to I (instead of one of them being A and the other X)?

Also, please share the dimensions of your matrix A.