When I try to use the forecast function in combination with a nlarx I get the following error: Unable to use a value of type idnlarx as an index
When I train the model and use the compare function everything works fine with no error message.
I am using the following code:
z = iddata(y_output, x_input, 1);
sys1 = nlarx(z(1:300),[15 15 1]);
forecast = 6;
figure(); compare(z(1:800), sys1, forecast);
Y_Pred = forecast(sys1, z(1:500), 6, z.u(501:506));
Can anyone help?
Thx in advance. Best regards