Problems with ipopt

[Matteo Fresia]

Hello, I am solving a Non-Linear Programming problem and I decided to use 'ipopt' solver. I have installed correctly the related package. Once I run the matlab code, this errore appears.

+ Solver chosen : ipopt-standard
+ Processing objective function
+ Processing constraints
+ Calling IPOPT
+ Calling IPOPT

******************************************************************************
This program contains Ipopt, a library for large-scale nonlinear optimization.
 Ipopt is released as open source code under the Eclipse Public License (EPL).
         For more information visit http://projects.coin-or.org/Ipopt
******************************************************************************

Matlab exception:
Unknown exception
*** Error using Ipopt Matlab interface: ***
There was an error when executing the gradient callback function.

Exception of type: IpoptException in file "Unknown File" at line -1:
 Exception message: Unknown Exception caught in Ipopt
Elapsed time is 18.605911 seconds.
Warning: Solver not found (gurobi)

I am not undestanding what is the problem. The fact is that on another PC the code is correctly working.

Thank you for the help

[Johan Löfberg]

You would have to supply a reproducible example. My guess is that you have ipopt compiled for different os/cpu/version etc and simply trigger a bug in ipopt

However, it is a bit weird that the warning is about gurobi, but ipopt has been called. Anyhow, reproducible example required