How to bound variable?

Dynare help (legacy posts)
1

Hello,

I have two general questions:

  1. Does Dynare solve models with inequalities?
    I need bound a variable in my model in interval [0,1]. Few others vars I have to make positive.
    I tryed:
    model;
    mu>=0;
    mu<=1;
    …
    But it doesn’t work.
    How can I bound variables in Dynare?

  2. May I determine exogenous variables within Dynare code?
    I’m trying to put an equation for exogenous variable ‘a’ :
    model;
    a = 0.9*a(-1);
    …
    but it results error: “exogenous variable has lag…”.

Thanks,
Oleg