using forecast in combination with nlarx gives an error

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));

%forecast(sys,past_data,K,future_inputs);

Can anyone help?

Thx in advance. Best regards

Answer 1

[Stefanie Schwarz]

The error message is caused by the variable "forecast=6" in your code that shadows the "forecast" function. Please rename the variable to something else.

For more info, see also:

https://www.mathworks.com/matlabcentral/answers/814915-why-do-i-get-the-error-unable-to-use-a-value-of-type-as-an-index