function [L,U,p] = lutx(A)
%LUTX  Triangular factorization, textbook version
%   [L,U,p] = lutx(A) produces a unit lower triangular matrix L,
%   an upper triangular matrix U, and a permutation vector p,
%   so that L*U = A(p,:)

[n,n] = size(A);
p = (1:n)';

for k = 1:n-1

   % Find index of largest element below diagonal in k-th column
   % [r,m] = max(abs(A(k:n,k)));
   %m = m+k-1;

   %Find index of largest element below diagonal in k-th column with for
   %loop
   
   g=0;
   for l = k:n
        if abs(A(l,k))>g
            g=abs(A(l,k));
            m=l;
        end
    end
    
   % Skip elimination if column is zero
   if (A(m,k) ~= 0)
   
      % Swap pivot row
      if (m ~= k)
         A([k m],:) = A([m k],:);
         p([k m]) = p([m k]);
      end

      % Compute multipliers
      %i = k+1:n;
      %A(i,k) = A(i,k)/A(k,k);
      for i=k+1: n
          A(i,k)=A(i,k)/A(k,k);
      end
      
      % Update the remainder of the matrix
      %j = k+1:n;
      %A(i,j) = A(i,j) - A(i,k)*A(k,j);     
      for i=k+1: n
          for j= k+1: n
              A(i,j)=A(i,j) - A(i,k)*A(k,j);
          end
      end
  end
end

% Separate result
L = tril(A,-1) + eye(n,n);
U = triu(A);
