% atime - Arrow that counts time starting from zero
%
% atime :: arrow({},{[1]},pair(empty,real)).
% atime :: DT:real -> arrow({},{[1]},pair(empty,real)).
%
% If no parameters are supplied, time increases by 1 each iteration.
% If one parameter DT is supplied, time increases by DT each iteration.
function a=atime(dt)
	if nargin<1, dt=1; end
	a=const(dt) * integrate(0);
end


