function I = Igrey(varargin)
% IGREY Returns a constant intensity as a function of time and space
%
% I = IGREY(x,t,greyvalue) returns intensity I(x,t) = greyvalue
% More precisely, returns I = greyvalue*ones(length(x),length(t))
% By convention, greyvalue = 0 is 50% grey.
%
% PERIOD = IGREY() returns 0, the period of the stimulus (i.e. constant)
% The PERIOD function was used in our implementation of
% the original Chance model to save memory (so that the intensity
% of only one cycle of the need be handled).
% It is not used for the present model.
%
% STRING = IGREY() returns string '{''greyvalue''}';
%
% Code written by SEAN CARVER, last modified 1252007
if nargin==0
I = '{greyvalue}';
elseif nargin < 2
I = 0;
else
x = varargin{1};
t = varargin{2};
greyvalue = varargin{3};
I = greyvalue*ones(length(x),length(t));
end
