I am not sure I understand your problem here. Are you trying to simulate the model with the TFP you observe? Is TFP the only shock exogenous variable in the model?
I assume that the TFP shock is the only source of randomness in the model:
\log A_t = \rho \log A_{t-1} + e_{A,t}
If you call the stoch_simul command, Dynare will simulate the model by taking draws for e_{A,t} in a normal distribution. If my understanding of your problem is correct, you want instead to simulate the model with the observed TFP. Here is what I would do:
- Compute recursively a sequence of innovations e_{A,T} consistent with your measure of TFP (assuming you have an initial condition A_0):
e_{A,t} = \log A_t - \rho \log A_{t-1}\quad \text{ for }t=1,\dots,T
- You need to call an internal matlab routine called
simult_(available in the matlab subfolder) providing the sequence (in a vector) obtained in the previous step as the third input (ex). You will figure out easily how to call this function by looking how we do it in Dynare (look atstoch_simul.mandsimult.min the same folder).
Best,
Stéphane