How to handle factorial or factorial-alike form?

This forum is closed. You can read the posts but cannot write. We have migrated the forum to a new location where you will have to reset your password.
Forum rules
This forum is closed. You can read the posts but cannot write. We have migrated the forum to a new location (https://forum.dynare.org) where you will have to reset your password.

How to handle factorial or factorial-alike form?

Postby Augustus » Tue Oct 05, 2010 6:37 am

I wonder how a factorial or a factorial-alike form could be handled with Dynare.

Just for simplicity, an example is as follows.

y(t)=y(t-1)+x(t)
x(t)=(1+1/1)*(1+1/2)*...* (1+1/t)

I have attempted to transform the factorial into

logx(t)=log(1+1/1)+log(1+1/2)...+log(1+1/t)

In recursive form: log(x(t))=log(x(t-1))+log(1+1/t)

In Dynare

y=y(-1)+x;
log(x)=log(x(-1))+log(1+1/t);
t=t(-1)+1

However, log(1+1/t) is a bit problematic, as t is introduced as a new variable and denotes the same time period to which y and x refer. Besides, I don't know how to assign an initial/a steady state value to the new variable t. How to deal with the scale of t is also a issue.

Thank you for your advance and tips!
Augustus
 
Posts: 1
Joined: Tue Oct 05, 2010 5:59 am

Re: How to handle factorial or factorial-alike form?

Postby jpfeifer » Mon Nov 08, 2010 10:08 pm

I am not sure, Dynare can handle such a setup. Dynare uses local solutions by approximation the decision rules around a well-defined steady state. In your case, I am not even sure such a steady state exists due to the trend in t.
------------
Johannes Pfeifer
University of Cologne
https://sites.google.com/site/pfeiferecon/
jpfeifer
 
Posts: 6940
Joined: Sun Feb 21, 2010 4:02 pm
Location: Cologne, Germany


Return to Dynare help

Who is online

Users browsing this forum: No registered users and 6 guests