[Ipopt] IpOpt code: Detereministic or Random across various runs?

[Tony Kelman]

Alireza,

Something you should try is "clear functions" and/or "clear global" between 
invocations of Ipopt - there may be some internal state somewhere in the mex 
file or in your callback functions. There shouldn't be, but it's possible. 
Also check that your objective and constraint functions are returning dense 
vectors - in the patch that Stefan linked to, I only test for and fix the 
issue for the gradient function. I thought it would be much less likely for 
anyone to write objective or constraint functions that return sparse 
vectors, but that might also lead to similar strange behavior if it were the 
case.

-Tony