General Question regarding Stability

[Daniel Bendel]

Dear Dynare-Users,

1. I was thinking about the following topic: a model can have an unit root, that means that the system dose not converge back to the inital steady state but reaches a new steady state following an exogenous shock. Is that right? Does dynare calculates this new steady state?

2. When we say, that a model is unstable, it does mean that the system does not converge back to its intial steady state and also does not converege to a new steady state in fact it never converges.
My model is unstable, I know dynare does not give out the policy function. But why? It is simply a matrix which eigenvalues does not fulfill the BK conditions. So it is calculable. In order to understand why my model is unstable, it would be nice to have the policy function even if it does not fulfill the BK conditions. Is there any way to get this matrix?

In fact I am talking about the oo_.dr.ghx and oo_.dr.ghu matrices.

Thank you!

Daniel