How do I get the upper triangular matrix in Gauss Elimination?

for i=1:N-1

for j=i+1:N

if A(i)==A(j)==0

disp('The matrix cannot be solved');

Aprime(j)=Aprime(j)*(-(Aprime(i,i)/Aprime(j,i));

bprime(j)=bprime(j)*(-(Aprime(i,i)/Aprime(j,i));

How do I multiply row j of A' and b'by -a'ii/a'ji (where ii and ji are the subscripts)

How do I add row i and row j of A' and b'?

[Rachel]

function [x, Aprime, bprime] = Gauss(A, b)

Aprime= A;

bprime= b;

Aprimebprime=[A,b];

[M,N]=size(Ab);

if (det (A))==0

   disp ('Cannot solve the matrix');

end

for i=1:N-1

    for j=i+1:N

        if Aprime(i)==Aprime(j)==0

            disp('The matrix cannot be solved');

Aprimebprime(i,j:M)=Aprimebprime(i,j:M)-Aprimebprime(i,i)/Aprimebprime(j,i)*Aprimebprime(j,j:M);

        Aprimebprime(i)=Aprimebprime(i)+Aprimebrime(j);

        x=Aprimebprime(i);

        end

    end

end

[Rachel]

Hello, I have written the coding for the above but it is not working out for some of the matrices. 1. A= [0 1 3 2;2 1 4 0;1 1 2 1;1 2 3 1]; b=[14;11;11;15] 2. A=[1 1;1 1]=b=[2;3]

If the diagonal elements are zero, it should display an error Kindly help me out with this.

Answer 1

[Sean de Wolski]

To error if there is a zero on the diagonal I would use the following:

assert(all(diag(A)),'Diagonal Element in A is zero')

And to show it working:

A = [1 2;3 4]
assert(all(diag(A)),'Diagonal Element in A is zero')
A = [1 2;3 0]
assert(all(diag(A)),'Diagonal Element in A is zero')