Matlab ODE function with changing arguments

2013-08-22

The main point is to differentiate between arguments and parameters. Arguments can change during the ODE integration steps, but parameters cannot. See this simple example:

clear;
param = struct('beta', 1000);
[T,Y] = ode45(@(t, y)odeFun(t, y, param),[0 3],[2 0]);
function dy = odeFun(t, y, param)
if t > 1
	param.beta = 50;
end
dy = zeros(2,1);    % a column vector
dy(1) = y(2);
dy(2) = -param.beta*y(1);