# Some questions with deterministic simulation

Dear Sir,
I use dynare 4.5.7 to simulat，I want to simulate in a deterministic model，but the results are very strange.The simulated trajectory map of consumption and capital stock is two straight lines， I wonder why there is no dynamics, many thanks!
simulation.mod (2.9 KB)

I get the message:

Failed to solve perfect foresight model

That should explain the output. You are getting returned the starting values. Try 4.6.3 with

``````simul (periods = 200,robust_lin_solve);
``````

Thank you, dear professor with this method, my problem has been solved, you are the benchmark of my study！

Dear Dr.feifer,I am doing deterministic simulation experiments with different shocks recently, but MATLAB there are errors in the running process, I do not know how to solve these errors, please guide (3.0 KB)

Are you sure your shock size is correct? Shouldn’t the shocks be smaller by a factor of 100? In nonlinear models that matters.

My two shocks are labor shock and money supply shock respectively. Do you mean to set both shocks to less than one？

What I am saying is that if your model variables are in logs and therefore in percent, then specifying

``````shocks;
var em0;
periods 2:6;
values 1.8;
end;
``````

for

``````m0-log(m0s)=rhom0*(m0(-1)-log(m0s))+em0;  %m0冲击
``````

implies that each period there is 1.8=180% shock happening. If you want 1.8%, then use `0.018`. Also check whether you want `m0` to be above steady state by this value or whether you want to shock it every period by this value. In the latter case, the deviations will accumulate massively.

Okay, prof. feifer, I see what you mean

They are not the same. Do

``````rplot m ;
rplot l;
rplot m0;
``````

to see that the second simply causes tiny movements that are dwarfed by the other shock.