// iterate over one evolution of the search algorithm
void gasearch_evolve(gasearch _g)
{
// Inject random chromosome at end
chromosome_init_random(_g->population[_g->population_size-1]);
// Crossover
gasearch_crossover(_g);
// Mutation
gasearch_mutate(_g);
// Evaluation
gasearch_evaluate(_g);
// Rank
gasearch_rank(_g);
if ( optim_threshold_switch(_g->utility_opt,
_g->utility[0],
_g->minimize) )
{
// update optimum
_g->utility_opt = _g->utility[0];
// copy optimum chromosome
chromosome_copy(_g->population[0], _g->c);
#if LIQUID_DEBUG_GA_SEARCH
printf(" utility: %0.2E", _g->utility_opt);
chromosome_printf(_g->c);
#endif
}
}
// Execute the search
// _g : ga search object
// _max_iterations : maximum number of iterations to run before bailing
// _tarutility : target utility
float gasearch_run(gasearch _g,
unsigned int _max_iterations,
float _tarutility)
{
unsigned int i=0;
do {
i++;
gasearch_evolve(_g);
} while (
optim_threshold_switch(_g->utility[0], _tarutility, _g->minimize) &&
i < _max_iterations);
// return optimum utility
return _g->utility_opt;
}
float qnsearch_run(qnsearch _q,
unsigned int _max_iterations,
float _target_utility)
{
unsigned int i=0;
do {
i++;
qnsearch_step(_q);
_q->utility = _q->get_utility(_q->userdata, _q->v, _q->num_parameters);
} while (
optim_threshold_switch(_q->utility, _target_utility, _q->minimize) &&
i < _max_iterations);
return _q->utility;
}
// rank population by fitness
void gasearch_rank(gasearch _g)
{
unsigned int i, j;
float u_tmp; // temporary utility placeholder
chromosome c_tmp; // temporary chromosome placeholder (pointer)
for (i=0; i<_g->population_size; i++) {
for (j=_g->population_size-1; j>i; j--) {
if ( optim_threshold_switch(_g->utility[j], _g->utility[j-1], !(_g->minimize)) ) {
// swap chromosome pointers
c_tmp = _g->population[j];
_g->population[j] = _g->population[j-1];
_g->population[j-1] = c_tmp;
// swap utility values
u_tmp = _g->utility[j];
_g->utility[j] = _g->utility[j-1];
_g->utility[j-1] = u_tmp;
}
}
}
}
// sort values by index
// _v : input values [size: _len x 1]
// _rank : output rank array (indices) [size: _len x 1]
// _len : length of input array
// _descending : descending/ascending
void optim_sort(float *_v,
unsigned int * _rank,
unsigned int _len,
int _descending)
{
unsigned int i, j, tmp_index;
for (i=0; i<_len; i++)
_rank[i] = i;
for (i=0; i<_len; i++) {
for (j=_len-1; j>i; j--) {
//if (_v[_rank[j]]>_v[_rank[j-1]]) {
if ( optim_threshold_switch(_v[_rank[j]], _v[_rank[j-1]], _descending) ) {
// swap elements
tmp_index = _rank[j];
_rank[j] = _rank[j-1];
_rank[j-1] = tmp_index;
}
}
}
}