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The Hessian is negative

PostPosted: Fri Jun 30, 2017 10:12 am
by phuong.macro
Hi all

after finding the global mode with the mode_compute = 7 (many number of interation and number of fuction evaluation as well) then the likelihood of -2197.2944 can not be improved anymore, Dynare also report that the Hessian matrix is negative. So that MH algorithm can not be computed.
I try with another mode_compute, for example, 4 and 9, but the Hessian is still negative in Dynare and the likelihood of -2197.2944 can not be improved anymore either
Anyone has a good suggestion for me?
Thank a lot

Re: The Hessian is negative

PostPosted: Fri Jun 30, 2017 10:37 am
by Robert
What happens if you try mode_compute = 6? This one is Monte-Carlo based. Another option would be that you load your last mode file and keep searching for the posterior mode. Use the mode_file = yourfile option in the estimation command.

Re: The Hessian is negative

PostPosted: Fri Jun 30, 2017 12:23 pm
by phuong.macro
Hello Robert

Thank you for your suggestion
But I did it already before asking for help (mode_file=ALEstim_phuong_mode) and try to use another method_mode, for example 9 which seem to be the best mode finder. But the hessian matrix is still negative

Re: The Hessian is negative

PostPosted: Fri Jun 30, 2017 12:27 pm
by jpfeifer
What do the mode_check plots say where the problem is?

Re: The Hessian is negative

PostPosted: Fri Jun 30, 2017 1:35 pm
by phuong.macro
Dear Prof. Pfeifer

I wound to attach all my files a long with data. It is convenient for me to describe what is going on with my model

Re: The Hessian is negative

PostPosted: Sat Jul 01, 2017 3:57 pm
by michall23full
I recommend to begin with mode_compute=6 (it always results in positive definite Hessian) and then try another mode-finder e.g. 9 providing result file from 6 as mode_file.

Re: The Hessian is negative

PostPosted: Sun Jul 02, 2017 10:15 am
by jpfeifer
You did not provide the mode-file. Please upload everything in one zip-file

Re: The Hessian is negative

PostPosted: Mon Jul 03, 2017 9:47 am
by phuong.macro
Dear Prof. Pfeifer

I would attach all file as zip file which include the mode_file

Re: The Hessian is negative

PostPosted: Mon Jul 03, 2017 9:51 am
by phuong.macro
Dear michall23full

but mode_compute= 6, It's not an optimization routine!... Or a very inefficient one

Re: The Hessian is negative

PostPosted: Mon Jul 03, 2017 2:15 pm
by jpfeifer
You can clearly see that your "mode" is not at the maximum for b and rdeltay (which are also far away from the prior mode). Try to understand why the model/data push the estimates to that region.

Re: The Hessian is negative

PostPosted: Wed Jul 12, 2017 7:53 am
by phuong.macro
Yes thank you Prof.Pfeifer