AMPL’s presolve phase, which runs before your problem is sent to Gurobi, is reporting this error:
presolve: constraint Conic1[1] cannot hold:
body <= -2.7832 cannot be >= -2.7832; difference = -4.44089e-16
Setting $presolve_eps >= 5.33e-16 might help.
Basically, presolve is telling you that there is a very slight infeasibility in your constraints. An infeasibility that small is not of any importance, so you should tell presolve to ignore it, by setting the presolve_eps option to a small positive value – as the message suggests. For example, you could try
option presolve_eps 1.0e-15;
since Gurobi’s infeasibility tolerance is actually a lot greater than that.
