Gass Elimination no pivot

%Write a MATLAB function to perform Gauss elimination (no pivoting). The function declaration should be 
B=[A,y];
[n,m]=size(B);
%Start with Foward sub
for i=1:n
    B(i,:)=B(i,:)./B(i,:);
    for k=i+1:n
        B(k,:)=(-B(i,:)*B(k,i))+B(k,:);
    end 
end 

%Back Substitution 
for j=n-1:-1:1
    for z=j+1:1:n
        B(j,:)=(-B(z,:)*B(j,z))+B(j,:);
    end 
end  

So my problem is I was given this code and was asked to "Write a MATLAB function to perform Gauss elimination (no pivoting). The function declaration should be function x = gausselim(A,y)". Then it asked to submit the code and the results. My problem is I do not understand how I am suposted to display results from just that. Thank you for your help

Answer 1

[KSSV]

function x = GaussElim(A, b)
% Solve linear system Ax = b
% using Gaussian elimination without pivoting
% A is an n by n matrix
% b is an n by k matrix (k copies of n-vectors)
% x is an n by k matrix (k copies of solution vectors)
[n, n] = size(A);     % Find size of matrix A
[n, k] = size(b);     % Find size of matrix b

x = zeros(n,k);      % Initialize x
for i = 1:n-1
    m = -A(i+1:n,i)/A(i,i); % multipliers
    A(i+1:n,:) = A(i+1:n,:) + m*A(i,:);
    b(i+1:n,:) = b(i+1:n,:) + m*b(i,:);
end;
% Use back substitution to find unknowns
x(n,:) = b(n,:)/A(n,n);
for i = n-1:-1:1
    x(i,:) = (b(i,:) - A(i,i+1:n)*x(i+1:n,:))/A(i,i);
end

Call:

A = rand(3) ; 
b = rand(3,1) ; 
x = GaussElim(A,b)