Hi I am trying to solve a model using couenne in the AMPL IDE. Couenne seems to run and gives an optimisation value but then it prints the following statement;
"Error at _cmdno 2 executing "solve" command (file V1.run, line 5, offset 57): Solution obtained using an unauthorized or unknown solver."
This line -> (file V1.run, line 5, offset 57) is just solve; in the run file.
This means I can't print some of the decision varaibles that I want to see.
Also a bit weird to note is that when I reduce some of the set sizes, and reduce the number of decision variables I have this message disappears. Anyone know how to fix this.
Sorry if it's a dumb question I'm still new at using AMPL
That message occurs with AMPL CE licenses when the solver used is not known or not allowed to use with AMPL CE. This verifications is only made above a certain model size and that is why the message would go away on smaller models.
In this case Couenne is allowed to be used with AMPL CE but it was being rejected by mistake. In order to fix this issue, you have to download a new AMPL CE bundle and replace your current installation as the problem has just been fixed.
Disclaimer: I am from AMPL.