ASA

Additionally other constraint types may also be added. For an unfeasible point the user defined objective function will return an invalid state, therefore a TOO_MANY_INVALID_STATES error may occur for problems where it is difficult to obtain feasible points.

ASA is a solver implemented by Lester Ingber. The ASA AMPL interface was developed by Ismael Vaz in order to benchmark the PSwarm solver with a set of problems. The interface is inspired in the ASAMIN MATLAB interface to ASA.

ASA makes no use of derivative information of the objective function (so modest problem size should be submitted).

For further information about ASA interface to AMPL, contact aivaz@dps.uminho.pt.

For further information about ASA contact the ASA author.

Using the NEOS Server for ASA

AMPL input

The model is specified by a model file, and optionally, a data file and a commands file. If the command file is specified it must contain the AMPL solve command.

The commands file can contain any AMPL command or set options for ASA with, for example,

option asa_options "maxf=1000";

Options include any of the parameters

• acceptance_frequency_modulus - Acceptance frequency modulus (integer)
• accepted_to_generated_ratio - Accepted to generated ratio (double)
• cost_parameter_scale - Cost parameter scale (double)
• cost_precision - Cost precision (double)
• delta_x - Delta x (double)
• generated_frequency_modulus - Generated frequency modulus (integer)
• include_integer_parameters - Include integer parameters (integer)
• initial_parameter_temperature - Initial parameters temperature (double)
• limit_acceptances - Limit acceptances (integer)
• limit_generated - Limit generated times problem dimension (integer)
• limit_invalid - Limit invalid (integer)
• maxf - Maximum number of function evaluations (integer)
• maximum_cost_repeat - Maximum cost repeat (integer)
• number_cost_samples - Number cost samples (integer)
• rand_seed - Ramdom seed (integer)
• reanneal_cost - Reanneal cost (integer)
• reanneal_parameters - Reanneal parameters (integer)
• sequential_parameters - Sequential parameters (integer)
• temperature_anneal_scale - Temperature anneal scale (double)
• temperature_ratio_scale - Temperature ratio scale (double)
• user_initial_parameters - User initial parameters (integer)

Printing directed to standard out is returned to the user with the output.

Using the NEOS Server for ASA/AMPL

The user must submit a model in AMPL format. Examples are provided in the examples section of the AMPL website.

The problem must be specified in a model file. A data file and commands files may also be provided. If the commands file is specified, it must contain the AMPL solve command; however, it must not contain the model or data commands. The model and data files are renamed internally by NEOS.

The commands file may include option settings for the solver. To specify solver options, add

  option asa_options 'OPTIONS';