Regarding the error message in solving policy function

Hi everyone,

I have some question regarding the error message in solving policy function. After looking at the code and some references, I particularly do not understand the meaning of error 1: The model doesn’t determine the policy function uniquely and error 2: MJDGGES returns the following error code xx.

From the code dr1.m, info = 1 is execute when there is infinite element in a, that means is to check “any(isinf(a(:)))”. On the other hand, I would like to ask, why it leads to non-unique policy function?

Secondly, MJDGGES is used to perform Schur Decomposition to certain matrices. If there is error message, error 2 is prompted but I want to know the reason of triggering such error message. Particularly, how should the model is specified correctly to avoid such error message?

Thanks for your kind attention.