hello!~~I have a little question!~~

I want to ask~ if use linear model

   "bar"  means steady state~
    should i need to use other .mod file to solve steady state?
    or I can solve in the same .mod file? 

    thanks for everyone ^^

For a linear model, where your equations are written in deviations, you need to calculate your steady state separately. Either by hand (analytically or numerically) or alternatively using another MOD-file where you write the full nonlinear model (the save_params_and_steady_state and load_params_and_steady_state commands can help you to transfer the data from one MOD-file to the other).

If your model is not written in deviation, then you can replace the "bar"s by the STEADY_STATE operator.