function OK = rangechk(rangeval)
%  check a range vector argument

%  last modified 3 January 2008

OK = 1;
if size(rangeval,1) ~= 1 && size(rangeval,2) ~= 1, OK = 0; end
if length(rangeval) ~= 2,                          OK = 0; end
if rangeval(1) >= rangeval(2),                     OK = 0; end
