%ode_test1.m  used by sim_difeq.m
%    x is scalar independent variable
%    y is vector dependent variables
%   dy is vector first derivatives of dependent variables
function dy=ode_test1(x, y)
dy = zeros(4,1); % force a column vector
dy(1) = 1.0; % four constant derivatives
dy(2) = 2.0;
dy(3) = 3.0;
dy(4) = 4.0; 
end
