Hybrid NKM under commitment

Optimal Policy
1

Hello,
I want to compute the Hybrid nkm under commitment with Dynare but I am confused about the Model.
I solved the model before in matlab by using The Targeting, Phillips Curve and the Shock equation. The System only consists of these three equations. The IS- curve wont be used coz it is not binding.

Iam not sure what to do with the Targeting Rule and the IS in Dynare.
Is there any hint to give me for solving my Problem?

The code I have used:

var pi ypsi x i ;
varexo eps;
parameters beta gamma_f gamma_b k AR_par phi alpha sigma;

sigma= 1;
beta = 1;
phi = 0.5;
k =0.2;
gamma_f= 0.5;
gamma_b= 0.5;
AR_par= 0.8;
alpha = 0.02;

model;
pi = beta*(gamma_fpi(+1) + gamma_bpi(-1))+ kx + ypsi;
ypsi = AR_parypsi(-1) + eps;
i = ((1-phi)x(+1)+phi(x-1)-x)*sigma + pi(+1);
end;

shocks;
var eps = alpha^2;
end;

planner_objective(1/2pi^2+1/2lambda*x^2);
ramsey_policy(planner_discount=0.99,order=1);

Thanks in advance

2

Have a look at https://github.com/JohannesPfeifer/DSGE_mod/blob/master/Gali_2015/Gali_2015_chapter_5_commitment.mod

3

Thanks… I solved the model with the aid of your example.

The output, inflation and shock process are plotted correclty but the interest rate has still a negative part, which is wrong. I can’t find the cause for the negaive part, because the interest rate is just derived from the IS curve.

4

What do you mean with