% foldcols - fold from left combinator for columns of an array
%
% foldcols :; 
%    (A,[[N]]->A) ~'folding function',
%    A            ~'initial value',
%    [[N,L]]      ~'data to scan, sequence of length L'
% -> A.

function y=foldcols(f,y,X)
	for i=1:size(X,2), y=f(y,X(:,i)); end
end
	

