TRON Directives for AMPL

To set these directives, assign a string specifying their values to the AMPL option tron_options. For example:

ampl: option tron_options 'itermax=100 gtol=1.0e-8';

Directives:

itermax     the limit on the number of conjugate gradient iterations.
maxfev      the limit on the number of function evaluations
fatol       the absolute error desired in the function
frtol       the relative error desired in the function
fmin        a lower bound for the function
cgtol       convergence criteria for the conjugate gradient method
gtol        relative 2-norm of projected grdients; convergence criteria
            for the trust region method