To set these options, assign a string specifying their values to the AMPL option `gecode_options`. For example:

ampl: option gecode_options 'version nodelimit=30000 val_branching=min';

`a_d`- Adaptive recomputation distance.

`c_d`- Commit recomputation distance.

`countsolutions`- 0 or 1 (default 0): Whether to count the number of solutions and return it in the
`.nsol`problem suffix.

`decay`- Decay factor for AFC and activity branchings. Default = 1.

`faillimit`- Fail limit.

`icl`Consistency level for integer propagators. Possible values:

`val`value propagation or consistency (naive) `bnd`bounds propagation or consistency `dom`domain propagation or consistency `def`the default consistency for a constraint

`nodelimit`- Node limit.

`outfreq`- Output frequency in seconds. The value should be a positive number.

`outlev`- 0 or 1 (default 0): Whether to print solution log.

`restart`Restart sequence type. Possible values:

`none`no restarts `constant`restart with constant sequence `linear`restart with linear sequence `luby`restart with Luby sequence `geometric`restart with geometric sequence

`restart_base`- Base for geometric restart sequence. Default = 1.5.

`restart_scale`- Scale factor for restart sequence. Default = 250.

`solutionlimit`- Limit on the number of feasible solutions found before terminating a search. Leaving the solution limit unspecified will make the optimizer search for an optimal solution if there is an objective function or for a feasible solution otherwise.

`solutionstub`- Stub for solution files. If
`solutionstub`is specified, found solutions are written to files (`solutionstub & '1' & '.sol'`) … (`solutionstub & Current.nsol & '.sol'`), where`Current.nsol`holds the number of returned solutions. That is, file names are obtained by appending 1, 2, …`Current.nsol`to`solutionstub`.

`threads`The number of parallel threads to use. Assume that your computer has m processing units and that the value for threads is n.

- If n = 0, then m threads are used (as many as available processing units).
- If n >= 1, then n threads are used (absolute number of threads to be used).
- If n <= −1, then m + n threads are used (absolute number of processing units not to be used). For example, when n = −6 and m = 8, then 2 threads are used.
- If 0 < n < 1, then n * m threads are used (relative number of processing units to be used). For example, when n = 0.5 and m = 8, then 4 threads are used.
- If −1 < n < 0, then (1 + n) * m threads are used (relative number of processing units not to be used). For example, when n = −0.25 and m = 8, then 6 threads are used.

All values are rounded and at least one thread is used.

`timelimit`- Time limit in seconds.

`timing`- 0 or 1 (default 0): Whether to display timings for the run.

`val_branching`Value branching. Possible values:

`min`smallest value (default) `med`greatest value not greater than the median `max`largest value `rnd`random value `split_min`values not greater than mean of smallest and largest value `split_max`values greater than mean of smallest and largest value `range_min`values from smallest range, if domain has several ranges; otherwise, values not greater than mean of smallest and largest value `range_max`values from largest range, if domain has several ranges; otherwise, values greater than mean of smallest and largest value `values_min`all values starting from smallest `values_max`all values starting from largest

`var_branching`Variable branching. Possible values:

`none`first unassigned `rnd`random `degree_min`smallest degree `degree_max`largest degree `afc_min`smallest accumulated failure count (AFC) `afc_max`largest accumulated failure count (AFC) `activity_min`lowest activity `activity_max`highest activity `min_min`smallest minimum value `min_max`largest minimum value `max_min`smallest maximum value `max_max`largest maximum value `size_min`smallest domain size (default) `size_max`largest domain size `degree_size_min`smallest domain size divided by degree `degree_size_max`largest domain size divided by degree `afc_size_min`smallest domain size divided by AFC `afc_size_max`largest domain size divided by AFC `activity_size_min`smallest activity by domain size `activity_size_max`largest activity by domain size `regret_min_min`smallest minimum-regret `regret_min_max`largest minimum-regret `regret_max_min`smallest maximum-regret `regret_max_max`largest maximum-regret

`version`- Single-word phrase: report version details before solving the problem.

`wantsol`In a stand-alone invocation (no

`-AMPL`on the command line), what solution information to write. Sum of1 – write`.sol`file2 – primal variables to stdout4 – dual variables to stdout8 – suppress solution message