NK_baseline_steadystate.m: provide proper error handling

(cherry picked from commit ab6b6425)

examples/NK_baseline_steadystate.m

@@ -65,6 +65,7 @@ Lambdax=mu_z;
 %set the parameter gammma1
 gammma1=mu_z*mu_I/betta-(1-delta);
 if gammma1<0 % parameter violates restriction; Preventing this cannot be implemented via prior restriction as it is a composite of different parameters and the valid prior region has unknown form
+    params=M_.params;
     check=1; %set failure indicator
     return; %return without updating steady states
 end
@@ -86,13 +87,20 @@ vp=(1-thetap)/(1-thetap*PI^((1-chi)*epsilon))*PIstar^(-epsilon);
 vw=(1-thetaw)/(1-thetaw*PI^((1-chiw)*eta)*mu_z^eta)*PIstarw^(-eta);
 tempvaromega=alppha/(1-alppha)*w/r*mu_z*mu_I;
 
+try
+    %proper error handling for cases for infeasible initial value, which would result in error instead of valid exitflag
     [ld,fval,exitflag]=fzero(@(ld)(1-betta*thetaw*mu_z^(eta-1)*PI^(-(1-chiw)*(1-eta)))/(1-betta*thetaw*mu_z^(eta*(1+gammma))*PI^(eta*(1-chiw)*(1+gammma)))...
         -(eta-1)/eta*wstar/(varpsi*PIstarw^(-eta*gammma)*ld^gammma)*((1-h*mu_z^(-1))^(-1)-betta*h*(mu_z-h)^(-1))*...
         ((mu_A*mu_z^(-1)*vp^(-1)*tempvaromega^alppha-tempvaromega*(1-(1-delta)*(mu_z*mu_I)^(-1)))*ld-vp^(-1)*Phi)^(-1),0.25,options);
+catch
+    exitflag = 0;
+end
+
 if exitflag <1
     %indicate the SS computation was not sucessful; this would also be detected by Dynare
     %setting the indicator here shows how to use this functionality to
     %filter out parameter draws
+    params=M_.params;
     check=1; %set failure indicator
     return; %return without updating steady states
 end