call function from Matlab Simulink to M File ?

Please,help me i have a Matlab Simulink Model which it`s output is Error .This output (error) I have to minimize it( USING GENETIC ALGORITHM ) by controlling three variables(Kp& ki& Kd) which included in the output.Due to this variables I can`t scope the output,and call this output in an M File

Can any one help me please to call this output in an M File. Thank

Answer 1

[Walter Roberson]

You can use a MATLAB Function Block in which the three variables are signals that are input. Or in which the three variables are defined as output signals.