Robert Fourer

You seem to be asking a new question about time limits, which is only indirectly related to the previous posts in this thread. Also, your question is more about how to use AMPL than how to use Guro...

You are setting gurobi_options twice: option gurobi_options 'timelimit=100 outlev=1 mipgap=0 mipfocus=3';option gurobi_options 'logfile=C:\AMPL\2023_01_29\Replication01\logfile.temp';  The second s...

That is a correct way to set the Gurobi time limit, and it's verified to be working with Gurobi 11.0 for AMPL. To be sure you are using it correctly, look for timelimit=7200 or lim:time=7200 in AMP...

Hey bot! Couldn't you use Model.addGenConstrExp()?

Does the setting of Gurobi parameter PreQLinearize make any difference in this situation?

You can write a formulation such as the following in AMPL, and it will be accepted by the AMPL-Gurobi interface: subj to cons1 {i in 2..N+1}:   x1[i] - x1[i-1] - x2[i-1] * x3[i-1] * cos(x4[i-1]) >=...

The reset_initial_guesses setting works, but if it does not make a big difference, then you can conclude that the slower solves are likely not due to warm starts. Here are some additional checks th...

I wouldn't expect that warmstarting would slow down Gurobi's solution process. But you can try turning off warmstarting by setting "option reset_initial_guesses 1;" in AMPL. It is possible that the...

In J.A. Tomlin, "On Scaling Linear Programming Problems," Mathematical Programming Study 4 (1975) 146-166, geometric mean scaling is defined as follows: Gurobi may be doing something of this sort....

AMPL accepts this model without any errors. It is OK to write the objective as the sum of three variables, each of which equals a different expression. The expression for f2[i,j] has a product of 3...