Modifying an algorithm to perform BLAS1 operations

I am asked to modify the following algorithm (LU decomposition of A) to perform BLAS1 operations instead of scalar operations. How can this be done? How will the algorithm be modified?

function [L,U] = ColLU(A)

n = size(A);

for k = 1:n-1

piv = A(k, k);

for i = k+1:n

A(i, k) = A(i, k)/piv;

end

for j = k+1:n

for i = k+1:n

A(i,j) = A(i,j)- A(i, k) * A(k, j);

end

end

end

U = triu(A)

L = tril(A, -1) + eye(n)