Solution interpretation in AMPL

[Leo]

Hello,

after solving a problem using Minos 5.51, I get this solution : 

optimal solution found. 16 iterations, objective 17 Nonlin evals: obj = 3, grad = 2.

What does Nonlin evals: obj = 3, grad = 2. stand for? Does grad mean the value of the gradient of the solution?

Thanks in advance for your answer

[AMPL Google Group]

In general, the result message from MINOS will look like this:

MINOS 5.51: optimal solution found.
99 iterations, objective 365186.1905
Nonlin evals: obj = 189, grad = 188, constrs = 189, Jac = 188.

The "Nonlin evals" counts tell you the number of times that MINOS evaluated various nonlinear functions:

• obj: number of evaluations of the objective function
• grad: number of evaluations of the gradient vector of the objective function
• constrs: number of evaluations of the nonlinear constraint functions
• Jac: number of evaluations of the Jacobian matrix of the nonlinear constraint functions

The obj and grad counts do not appear when the objective function is linear. The constrs and Jac counts do not appear when all of the constraints are linear.

--
Robert Fourer
am...@googlegroups.com

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