MATLAB Function Interface Error: Error calling MATLAB function 'sim'

I am calling sim function in a user defined matlab function block to test the inputs using neural network trained data stored in 'net' variable, I get this error

MATLAB Function Interface Error: Error calling MATLAB function 'sim'. Block Neural Network Function (#108) While executing: none

My code is

function [tau1p,tau2p]  = Nntwork(theta1,theta1d,theta2,theta2d,theta1dd,theta2dd)
coder.extrinsic('load');
coder.extrinsic('sim');
net=load('trainednet.mat');
a=sim(net,[theta1;theta1d;theta1dd;theta2;theta2d;theta2dd]);
tau1p=1;
tau2p=a2;

[XIN HE]

I met with the similar proble, have you solved it ?

[Walter Roberson]

I wonder if the difficulty is related to the fact that sim() is a method of neural networks but also the function to invoke simulink ?

Code generation does not appear to be possible with the neural network sim method, so this code would not work with rapid acceleration turned on.

[XIN HE]

Thanks. Your answer makes some sense. I think mabye I have to try some other ways.