function B = haar_col(A);

% This function performs sums and differences column-wise for the Haar
% Transform. The result is then placed back into the input matrix.

n = length(A);
for j = 1:n
num = 1;
for i = 1:2:(n-1)
B(num,j) = (A(i,j) + A(i+1,j))/sqrt(2);
B(num + n/2,j) = (A(i,j) - A(i+1,j))/sqrt(2);
num = num + 1;
end
end