Dear all,

I am studying the second order approximation ramsey policy with Uribe & Schmitt-Grohe’s code(JME, 2007).

Their model is in the attached file appendix B (pp46), jme_revision_expanded.pdf (448.0 KB)

And they have constraints codes like this file for above 16 equations as e1_cu~e16_cu, constraints.m (5.3 KB)

I try to revise their codes to mine, but I can’t understand some parts realted to “time”.

Among their code files, I don’t know the logic how to select the variables in ramsey_f.m file.ramsey_f.m (4.5 KB)

- For “time”,they use codes as follow;

t-2 : ba2

t-1 : ba2p or ba1

t : ba1p or cu

t+1 : cup or fu1

t+2 : fu1p

Please see attached ramsey_f.m file from line19th~24th.

%Replace all variables that appear in foc as _fu1 but not as _fu1p by variables in _cup

**fu1only = [h_fu1 iv_fu1 k_fu1 la_fu1 mc_fu1 pai_fu1 q_fu1 xi14_fu1 xi16_fu1 xi1_fu1 xi4_fu1 xi7_fu1 xi8_fu1 z_fu1 ];**

fu1only2cup = [h_cup iv_cup k_cup la_cup mc_cup pai_cup q_cup xi14_cup xi16_cup xi1_cup xi4_cup xi7_cup xi8_cup z_cup ];

foc=subs(foc,fu1only, fu1only2cup);

h~q are eondogenous variables and xi14~xi8 are lagrangian multipliers, which are selected among lots of engogenous variabels and 16 constraints.

[h_fu1 iv_fu1 k_fu1 la_fu1 mc_fu1 pai_fu1 q_fu1 xi14_fu1 xi16_fu1 xi1_fu1 xi4_fu1 xi7_fu1 xi8_fu1 z_fu1 ]

**I don’t know how to choose the variables which are matched to these in line 20th( [h_fu1 iv_fu1 k_fu1 la_fu1 mc_fu1 pai_fu1 q_fu1 xi14_fu1 xi16_fu1 xi1_fu1 xi4_fu1 xi7_fu1 xi8_fu1 z_fu1 ]), 27th and 36th.**

If someone have done this or known this, Please help me to know how to solve this problem~

Thank you for all,

Esther