Lower bound and prior_3rd_parameter

Dynare help (legacy posts)
8

Dear Johannes,

Could I ask more questions on this topic?

  1. As far as I know, 3rd/4th parameters specification should not influence mode-finding results, however, the following 2 priors get completely different mode results (initial value 1.3 , mean1.366, std0.2).

Why does this happen?

  1. For some reason, I have to use matlab code instead of dynare to estimate model. The key parameter "miu " should be always >1.
    If I truncate like this

pd=makedist('Gamma','a',1.366^2/0.2^2,'b',0.2^2/1.366); t=truncate(pd,1,inf); P1=pdf(t,Theta(1));

would that be correct? It corresponds to truncation of upper and lower bound?

  1. If I still confused to set truncated gamma pdf(>1) in matlab code, how about using this way:
    I set another parameter** “alpha=miu-1” **so that when miu>1 , alpha>0. Then I estimate alpha instead of miu using gamma distribution prior without truncation? Does that make sense?

Many many many thanks in advance!
Kind regards,
Huan