本文整理汇总了C++中population::get_individual方法的典型用法代码示例。如果您正苦于以下问题:C++ population::get_individual方法的具体用法?C++ population::get_individual怎么用?C++ population::get_individual使用的例子?那么, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类population
的用法示例。
在下文中一共展示了population::get_individual方法的15个代码示例,这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞,您的评价将有助于系统推荐出更棒的C++代码示例。
示例1: evolve
void ms::evolve(population &pop) const
{
// Let's store some useful variables.
const population::size_type NP = pop.size();
// Get out if there is nothing to do.
if (m_starts == 0 || NP == 0) {
return;
}
// Local population used in the algorithm iterations.
population working_pop(pop);
//ms main loop
for (int i=0; i< m_starts; ++i)
{
working_pop.reinit();
m_algorithm->evolve(working_pop);
if (working_pop.problem().compare_fc(working_pop.get_individual(working_pop.get_best_idx()).cur_f,working_pop.get_individual(working_pop.get_best_idx()).cur_c,
pop.get_individual(pop.get_worst_idx()).cur_f,pop.get_individual(pop.get_worst_idx()).cur_c
) )
{
//update best population replacing its worst individual with the good one just produced.
pop.set_x(pop.get_worst_idx(),working_pop.get_individual(working_pop.get_best_idx()).cur_x);
pop.set_v(pop.get_worst_idx(),working_pop.get_individual(working_pop.get_best_idx()).cur_v);
}
if (m_screen_output)
{
std::cout << i << ". " << "\tCurrent iteration best: " << working_pop.get_individual(working_pop.get_best_idx()).cur_f << "\tOverall champion: " << pop.champion().f << std::endl;
}
}
}
示例2: evolve
/// Evolve method.
void monte_carlo::evolve(population &pop) const
{
// Let's store some useful variables.
const problem::base &prob = pop.problem();
const problem::base::size_type prob_dimension = prob.get_dimension(), prob_i_dimension = prob.get_i_dimension();
const decision_vector &lb = prob.get_lb(), &ub = prob.get_ub();
const population::size_type pop_size = pop.size();
// Get out if there is nothing to do.
if (pop_size == 0 || m_max_eval == 0) {
return;
}
// Initialise temporary decision vector, fitness vector and decision vector.
decision_vector tmp_x(prob_dimension);
fitness_vector tmp_f(prob.get_f_dimension());
constraint_vector tmp_c(prob.get_c_dimension());
// Main loop.
for (std::size_t i = 0; i < m_max_eval; ++i) {
// Generate a random decision vector.
for (problem::base::size_type j = 0; j < prob_dimension - prob_i_dimension; ++j) {
tmp_x[j] = boost::uniform_real<double>(lb[j],ub[j])(m_drng);
}
for (problem::base::size_type j = prob_dimension - prob_i_dimension; j < prob_dimension; ++j) {
tmp_x[j] = boost::uniform_int<int>(lb[j],ub[j])(m_urng);
}
// Compute fitness and constraints.
prob.objfun(tmp_f,tmp_x);
prob.compute_constraints(tmp_c,tmp_x);
// Locate the worst individual.
const population::size_type worst_idx = pop.get_worst_idx();
if (prob.compare_fc(tmp_f,tmp_c,pop.get_individual(worst_idx).cur_f,pop.get_individual(worst_idx).cur_c)) {
pop.set_x(worst_idx,tmp_x);
}
}
}
示例3:
std::vector<population::individual_type> best_kill_s_policy::select(population &pop) const
{
pagmo_assert(get_n_individuals(pop) <= pop.size());
// Gets the number of individuals to select
const population::size_type migration_rate = get_n_individuals(pop);
// Create a temporary array of individuals.
std::vector<population::individual_type> result;
// Gets the indexes of the best individuals
std::vector<population::size_type> best_idx = pop.get_best_idx(migration_rate);
// Puts the best individuals in results
for (population::size_type i =0; i< migration_rate; ++i) {
result.push_back(pop.get_individual(best_idx[i]));
}
// Remove them from the original population
// (note: the champion will still carry information on the best guy ...)
for (population::size_type i=0 ; i<migration_rate; ++i) {
pop.reinit(best_idx[i]);
}
return result;
}
示例4: update_c_scaling
/**
* Updates the constraints scaling vector with the given population.
* @param[in] population pop.
*/
void cstrs_self_adaptive::update_c_scaling(const population &pop)
{
if(*m_original_problem != pop.problem()) {
pagmo_throw(value_error,"The problem linked to the population is not the same as the problem given in argument.");
}
// Let's store some useful variables.
const population::size_type pop_size = pop.size();
// get the constraints dimension
//constraint_vector c(m_original_problem->get_c_dimension(), 0.);
problem::base::c_size_type prob_c_dimension = m_original_problem->get_c_dimension();
problem::base::c_size_type number_of_eq_constraints =
m_original_problem->get_c_dimension() -
m_original_problem->get_ic_dimension();
const std::vector<double> &c_tol = m_original_problem->get_c_tol();
m_c_scaling.resize(m_original_problem->get_c_dimension());
std::fill(m_c_scaling.begin(),m_c_scaling.end(),0.);
// evaluates the scaling factor
for(population::size_type i=0; i<pop_size; i++) {
// updates the current constraint vector
const population::individual_type ¤t_individual = pop.get_individual(i);
const constraint_vector &c = current_individual.cur_c;
// computes scaling with the right definition of the constraints (can be in base problem? currently used
// by con2mo as well)
for(problem::base::c_size_type j=0; j<number_of_eq_constraints; j++) {
m_c_scaling[j] = std::max(m_c_scaling[j], std::max(0., (std::abs(c.at(j)) - c_tol.at(j))) );
}
for(problem::base::c_size_type j=number_of_eq_constraints; j<prob_c_dimension; j++) {
m_c_scaling[j] = std::max(m_c_scaling[j], std::max(0., c.at(j) - c_tol.at(j)) );
}
}
}
示例5: evolve
void sa_corana::evolve(population &pop) const {
// Let's store some useful variables.
const problem::base &prob = pop.problem();
const problem::base::size_type D = prob.get_dimension(), prob_i_dimension = prob.get_i_dimension(), prob_c_dimension = prob.get_c_dimension(), prob_f_dimension = prob.get_f_dimension();
const decision_vector &lb = prob.get_lb(), &ub = prob.get_ub();
const population::size_type NP = pop.size();
const problem::base::size_type Dc = D - prob_i_dimension;
//We perform some checks to determine wether the problem/population are suitable for sa_corana
if ( Dc == 0 ) {
pagmo_throw(value_error,"There is no continuous part in the problem decision vector for sa_corana to optimise");
}
if ( prob_c_dimension != 0 ) {
pagmo_throw(value_error,"The problem is not box constrained and sa_corana is not suitable to solve it");
}
if ( prob_f_dimension != 1 ) {
pagmo_throw(value_error,"The problem is not single objective and sa_corana is not suitable to solve it");
}
//Determines the number of temperature adjustment for the annealing procedure
const size_t n_T = m_niter / (m_step_adj * m_bin_size * Dc);
// Get out if there is nothing to do.
if (NP == 0 || m_niter == 0) {
return;
}
if (n_T == 0) {
pagmo_throw(value_error,"n_T is zero, increase niter");
}
//Starting point is the best individual
const int bestidx = pop.get_best_idx();
const decision_vector &x0 = pop.get_individual(bestidx).cur_x;
const fitness_vector &fit0 = pop.get_individual(bestidx).cur_f;
//Determines the coefficient to dcrease the temperature
const double Tcoeff = std::pow(m_Tf/m_Ts,1.0/(double)(n_T));
//Stores the current and new points
decision_vector xNEW = x0, xOLD = xNEW;
fitness_vector fNEW = fit0, fOLD = fNEW;
//Stores the adaptive steps of each component (integer part included but not used)
decision_vector step(D,m_range);
//Stores the number of accepted points per component (integer part included but not used)
std::vector<int> acp(D,0) ;
double ratio = 0, currentT = m_Ts, probab = 0;
//Main SA loops
for (size_t jter = 0; jter < n_T; ++jter) {
for (int mter = 0; mter < m_step_adj; ++mter) {
for (int kter = 0; kter < m_bin_size; ++kter) {
size_t nter = boost::uniform_int<int>(0,Dc-1)(m_urng);
for (size_t numb = 0; numb < Dc ; ++numb) {
nter = (nter + 1) % Dc;
//We modify the current point actsol by mutating its nter component within
//a step that we will later adapt
xNEW[nter] = xOLD[nter] + boost::uniform_real<double>(-1,1)(m_drng) * step[nter] * (ub[nter]-lb[nter]);
// If new solution produced is infeasible ignore it
if ((xNEW[nter] > ub[nter]) || (xNEW[nter] < lb[nter])) {
xNEW[nter]=xOLD[nter];
continue;
}
//And we valuate the objective function for the new point
prob.objfun(fNEW,xNEW);
// We decide wether to accept or discard the point
if (prob.compare_fitness(fNEW,fOLD) ) {
//accept
xOLD[nter] = xNEW[nter];
fOLD = fNEW;
acp[nter]++; //Increase the number of accepted values
} else {
//test it with Boltzmann to decide the acceptance
probab = exp ( - fabs(fOLD[0] - fNEW[0] ) / currentT );
// we compare prob with a random probability.
if (probab > m_drng()) {
xOLD[nter] = xNEW[nter];
fOLD = fNEW;
acp[nter]++; //Increase the number of accepted values
} else {
xNEW[nter] = xOLD[nter];
}
} // end if
} // end for(nter = 0; ...
} // end for(kter = 0; ...
// adjust the step (adaptively)
for (size_t iter = 0; iter < Dc; ++iter) {
ratio = (double)acp[iter]/(double)m_bin_size;
acp[iter] = 0; //reset the counter
if (ratio > .6) {
//too many acceptances, increase the step by a factor 3 maximum
step[iter] = step [iter] * (1 + 2 *(ratio - .6)/.4);
} else {
if (ratio < .4) {
//too few acceptance, decrease the step by a factor 3 maximum
step [iter]= step [iter] / (1 + 2 * ((.4 - ratio)/.4));
//.........这里部分代码省略.........
示例6: evolve
/**
* Runs the NN_TSP algorithm.
*
* @param[in,out] pop input/output pagmo::population to be evolved.
*/
void nn_tsp::evolve(population &pop) const
{
const problem::base_tsp* prob;
//check if problem is of type pagmo::problem::base_tsp
try
{
prob = &dynamic_cast<const problem::base_tsp &>(pop.problem());
}
catch (const std::bad_cast& e)
{
pagmo_throw(value_error,"Problem not of type pagmo::problem::tsp, nn_tsp can only be called on problem::tsp problems");
}
// Let's store some useful variables.
const problem::base::size_type Nv = prob->get_n_cities();
//create individuals
decision_vector best_tour(Nv);
decision_vector new_tour(Nv);
//check input parameter
if (m_start_city < -1 || m_start_city > static_cast<int>(Nv-1)) {
pagmo_throw(value_error,"invalid value for the first vertex");
}
size_t first_city, Nt;
if(m_start_city == -1){
first_city = 0;
Nt = Nv;
}
else{
first_city = m_start_city;
Nt = m_start_city+1;
}
int length_best_tour, length_new_tour;
size_t nxt_city, min_idx;
std::vector<int> not_visited(Nv);
length_best_tour = 0;
//main loop
for (size_t i = first_city; i < Nt; i++) {
length_new_tour = 0;
for (size_t j = 0; j < Nv; j++) {
not_visited[j] = j;
}
new_tour[0] = i;
std::swap(not_visited[new_tour[0]],not_visited[Nv-1]);
for (size_t j = 1; j < Nv-1; j++) {
min_idx = 0;
nxt_city = not_visited[0];
for (size_t l = 1; l < Nv-j; l++) {
if(prob->distance(new_tour[j-1], not_visited[l]) < prob->distance(new_tour[j-1], nxt_city) )
{
min_idx = l;
nxt_city = not_visited[l];}
}
new_tour[j] = nxt_city;
length_new_tour += prob->distance(new_tour[j-1], nxt_city);
std::swap(not_visited[min_idx],not_visited[Nv-j-1]);
}
new_tour[Nv-1] = not_visited[0];
length_new_tour += prob->distance(new_tour[Nv-2], new_tour[Nv-1]);
length_new_tour += prob->distance(new_tour[Nv-1], new_tour[0]);
if(i == first_city || length_new_tour < length_best_tour){
best_tour = new_tour;
length_best_tour = length_new_tour;
}
}
//change representation of tour
population::size_type best_idx = pop.get_best_idx();
switch( prob->get_encoding() ) {
case problem::base_tsp::FULL:
pop.set_x(best_idx,prob->cities2full(best_tour));
break;
case problem::base_tsp::RANDOMKEYS:
pop.set_x(best_idx,prob->cities2randomkeys(best_tour,pop.get_individual(best_idx).cur_x));
break;
case problem::base_tsp::CITIES:
pop.set_x(best_idx,best_tour);
break;
}
} // end of evolve
示例7: evolve
/**
* The best member of the population will be used as starting point for the minimisation process. The algorithm will stop
* if the gradient falls below the grad_tol parameter, if the maximum number of iterations max_iter is exceeded or if
* the inner GSL routine call reports an error (which will be logged on std::cout). After the end of the minimisation process,
* the minimised decision vector will replace the best individual in the population, after being modified to fall within
* the problem bounds if necessary.
*
* @param[in,out] pop population to evolve.
*/
void gsl_gradient::evolve(population &pop) const
{
// Do nothing if the population is empty.
if (!pop.size()) {
return;
}
// Useful variables.
const problem::base &problem = pop.problem();
if (problem.get_f_dimension() != 1) {
pagmo_throw(value_error,"this algorithm does not support multi-objective optimisation");
}
if (problem.get_c_dimension()) {
pagmo_throw(value_error,"this algorithm does not support constrained optimisation");
}
const problem::base::size_type cont_size = problem.get_dimension() - problem.get_i_dimension();
if (!cont_size) {
pagmo_throw(value_error,"the problem has no continuous part");
}
// Extract the best individual.
const population::size_type best_ind_idx = pop.get_best_idx();
const population::individual_type &best_ind = pop.get_individual(best_ind_idx);
// GSL wrapper parameters structure.
objfun_wrapper_params params;
params.p = &problem;
// Integer part of the temporay decision vector must be filled with the integer part of the best individual,
// which will not be optimised.
params.x.resize(problem.get_dimension());
std::copy(best_ind.cur_x.begin() + cont_size, best_ind.cur_x.end(), params.x.begin() + cont_size);
params.f.resize(1);
params.step_size = m_numdiff_step_size;
// GSL function structure.
gsl_multimin_function_fdf gsl_func;
gsl_func.n = boost::numeric_cast<std::size_t>(cont_size);
gsl_func.f = &objfun_wrapper;
gsl_func.df = &d_objfun_wrapper;
gsl_func.fdf = &fd_objfun_wrapper;
gsl_func.params = (void *)¶ms;
// Minimiser.
gsl_multimin_fdfminimizer *s = 0;
// This will be the starting point.
gsl_vector *x = 0;
// Here we start the allocations.
// Recast as size_t here, in order to avoid potential overflows later.
const std::size_t s_cont_size = boost::numeric_cast<std::size_t>(cont_size);
// Allocate and check the allocation results.
x = gsl_vector_alloc(s_cont_size);
const gsl_multimin_fdfminimizer_type *minimiser = get_gsl_minimiser_ptr();
pagmo_assert(minimiser);
s = gsl_multimin_fdfminimizer_alloc(minimiser,s_cont_size);
// Check the allocations.
check_allocs(x,s);
// Fill in the starting point (from the best individual).
for (std::size_t i = 0; i < s_cont_size; ++i) {
gsl_vector_set(x,i,best_ind.cur_x[i]);
}
// Init the solver.
gsl_multimin_fdfminimizer_set(s,&gsl_func,x,m_step_size,m_tol);
// Iterate.
std::size_t iter = 0;
int status;
try {
do
{
++iter;
status = gsl_multimin_fdfminimizer_iterate(s);
if (status) {
break;
}
status = gsl_multimin_test_gradient(s->gradient,m_grad_tol);
} while (status == GSL_CONTINUE && iter < m_max_iter);
} catch (const std::exception &e) {
// Cleanup and re-throw.
cleanup(x,s);
throw e;
} catch (...) {
// Cleanup and throw.
cleanup(x,s);
pagmo_throw(std::runtime_error,"unknown exception caught in gsl_gradient::evolve");
}
// Free up resources.
cleanup(x,s);
// Check the generated individual and change it to respect the bounds as necessary.
for (problem::base::size_type i = 0; i < cont_size; ++i) {
if (params.x[i] < problem.get_lb()[i]) {
params.x[i] = problem.get_lb()[i];
}
if (params.x[i] > problem.get_ub()[i]) {
params.x[i] = problem.get_ub()[i];
}
}
// Replace the best individual.
//.........这里部分代码省略.........
示例8: evolve
void ihs::evolve(population &pop) const
{
// Let's store some useful variables.
const problem::base &prob = pop.problem();
const problem::base::size_type prob_dimension = prob.get_dimension(), prob_i_dimension = prob.get_i_dimension();
const decision_vector &lb = prob.get_lb(), &ub = prob.get_ub();
const population::size_type pop_size = pop.size();
// Get out if there is nothing to do.
if (pop_size == 0 || m_gen == 0) {
return;
}
decision_vector lu_diff(prob_dimension);
for (problem::base::size_type i = 0; i < prob_dimension; ++i) {
lu_diff[i] = ub[i] - lb[i];
}
// Int distribution to be used when picking random individuals.
boost::uniform_int<population::size_type> uni_int(0,pop_size - 1);
const double c = std::log(m_bw_min/m_bw_max) / m_gen;
// Temporary individual used during evolution.
population::individual_type tmp;
tmp.cur_x.resize(prob_dimension);
tmp.cur_f.resize(prob.get_f_dimension());
tmp.cur_c.resize(prob.get_c_dimension());
for (std::size_t g = 0; g < m_gen; ++g) {
const double ppar_cur = m_ppar_min + ((m_ppar_max - m_ppar_min) * g) / m_gen, bw_cur = m_bw_max * std::exp(c * g);
// Continuous part.
for (problem::base::size_type i = 0; i < prob_dimension - prob_i_dimension; ++i) {
if (m_drng() < m_phmcr) {
// tmp's i-th chromosome element is the one from a randomly chosen individual.
tmp.cur_x[i] = pop.get_individual(uni_int(m_urng)).cur_x[i];
// Do pitch adjustment with ppar_cur probability.
if (m_drng() < ppar_cur) {
// Randomly, add or subtract pitch from the current chromosome element.
if (m_drng() > .5) {
tmp.cur_x[i] += m_drng() * bw_cur * lu_diff[i];
} else {
tmp.cur_x[i] -= m_drng() * bw_cur * lu_diff[i];
}
// Handle the case in which we added or subtracted too much and ended up out
// of boundaries.
if (tmp.cur_x[i] > ub[i]) {
tmp.cur_x[i] = boost::uniform_real<double>(lb[i],ub[i])(m_drng);
} else if (tmp.cur_x[i] < lb[i]) {
tmp.cur_x[i] = boost::uniform_real<double>(lb[i],ub[i])(m_drng);
}
}
} else {
// Pick randomly within the bounds.
tmp.cur_x[i] = boost::uniform_real<double>(lb[i],ub[i])(m_drng);
}
}
//Integer Part
for (problem::base::size_type i = prob_dimension - prob_i_dimension; i < prob_dimension; ++i) {
if (m_drng() < m_phmcr) {
tmp.cur_x[i] = pop.get_individual(uni_int(m_urng)).cur_x[i];
if (m_drng() < ppar_cur) {
if (m_drng() > .5) {
tmp.cur_x[i] += double_to_int::convert(m_drng() * bw_cur * lu_diff[i]);
} else {
tmp.cur_x[i] -= double_to_int::convert(m_drng() * bw_cur * lu_diff[i]);
}
// Wrap over in case we went past the bounds.
if (tmp.cur_x[i] > ub[i]) {
tmp.cur_x[i] = lb[i] + double_to_int::convert(tmp.cur_x[i] - ub[i]) % static_cast<int>(lu_diff[i]);
} else if (tmp.cur_x[i] < lb[i]) {
tmp.cur_x[i] = ub[i] - double_to_int::convert(lb[i] - tmp.cur_x[i]) % static_cast<int>(lu_diff[i]);
}
}
} else {
// Pick randomly within the bounds.
tmp.cur_x[i] = boost::uniform_int<int>(lb[i],ub[i])(m_urng);
}
}
// And we push him back
pop.push_back(tmp.cur_x);
// We locate the worst individual.
const population::size_type worst_idx = pop.get_worst_idx();
// And we get rid of him :)
pop.erase(worst_idx);
}
}
示例9: evolve
/**
* Runs the Inverover algorithm for the number of generations specified in the constructor.
*
* @param[in,out] pop input/output pagmo::population to be evolved.
*/
void inverover::evolve(population &pop) const
{
const problem::base_tsp* prob;
//check if problem is of type pagmo::problem::base_tsp
try {
const problem::base_tsp& tsp_prob = dynamic_cast<const problem::base_tsp &>(pop.problem());
prob = &tsp_prob;
}
catch (const std::bad_cast& e) {
pagmo_throw(value_error,"Problem not of type pagmo::problem::base_tsp");
}
// Let's store some useful variables.
const population::size_type NP = pop.size();
const problem::base::size_type Nv = prob->get_n_cities();
// Initializing the random number generators
boost::uniform_real<double> uniform(0.0, 1.0);
boost::variate_generator<boost::lagged_fibonacci607 &, boost::uniform_real<double> > unif_01(m_drng, uniform);
boost::uniform_int<int> NPless1(0, NP - 2);
boost::variate_generator<boost::mt19937 &, boost::uniform_int<int> > unif_NPless1(m_urng, NPless1);
boost::uniform_int<int> Nv_(0, Nv - 1);
boost::variate_generator<boost::mt19937 &, boost::uniform_int<int> > unif_Nv(m_urng, Nv_);
boost::uniform_int<int> Nvless1(0, Nv - 2);
boost::variate_generator<boost::mt19937 &, boost::uniform_int<int> > unif_Nvless1(m_urng, Nvless1);
//create own local population
std::vector<decision_vector> my_pop(NP, decision_vector(Nv));
//check if some individuals in the population that is passed as a function input are feasible.
bool feasible;
std::vector<int> not_feasible;
for (size_t i = 0; i < NP; i++) {
feasible = prob->feasibility_x(pop.get_individual(i).cur_x);
if(feasible) { //if feasible store it in my_pop
switch(prob->get_encoding()) {
case problem::base_tsp::FULL:
my_pop[i] = prob->full2cities(pop.get_individual(i).cur_x);
break;
case problem::base_tsp::RANDOMKEYS:
my_pop[i] = prob->randomkeys2cities(pop.get_individual(i).cur_x);
break;
case problem::base_tsp::CITIES:
my_pop[i] = pop.get_individual(i).cur_x;
break;
}
} else {
not_feasible.push_back(i);
}
}
//replace the not feasible individuals by feasible ones
int i;
switch (m_ini_type) {
case 0:
{
//random initialization (produces feasible individuals)
for (size_t ii = 0; ii < not_feasible.size(); ii++) {
i = not_feasible[ii];
for (size_t j = 0; j < Nv; j++) {
my_pop[i][j] = j;
}
}
int tmp;
size_t rnd_idx;
for (size_t j = 1; j < Nv-1; j++) {
boost::uniform_int<int> dist_(j, Nv - 1);
boost::variate_generator<boost::mt19937 &, boost::uniform_int<int> > dist(m_urng,dist_);
for (size_t ii = 0; ii < not_feasible.size(); ii++) {
i = not_feasible[ii];
rnd_idx = dist();
tmp = my_pop[i][j];
my_pop[i][j] = my_pop[i][rnd_idx];
my_pop[i][rnd_idx] = tmp;
}
}
break;
}
case 1:
{
//initialize with nearest neighbor algorithm
std::vector<int> starting_notes(std::max(Nv,not_feasible.size()));
for (size_t j = 0; j < starting_notes.size(); j++) {
starting_notes[j] = j;
}
//std::shuffle(starting_notes.begin(), starting_notes.end(), m_urng);
for (size_t ii = 0; ii < not_feasible.size(); ii++) {
i = not_feasible[ii];
pagmo::population one_ind_pop(pop.problem(), 1);
std::cout << starting_notes[i] << ' ';
pagmo::algorithm::nn_tsp algo(starting_notes[i] % Nv);
algo.evolve(one_ind_pop);
switch( prob->get_encoding() ) {
//.........这里部分代码省略.........
示例10: evolve
// Evolve method.
void base_nlopt::evolve(population &pop) const
{
// Useful variables.
const problem::base &problem = pop.problem();
if (problem.get_f_dimension() != 1) {
pagmo_throw(value_error,"this algorithm does not support multi-objective optimisation");
}
const problem::base::c_size_type c_size = problem.get_c_dimension();
const problem::base::c_size_type ec_size = problem.get_c_dimension() - problem.get_ic_dimension();
if (c_size && !m_constrained) {
pagmo_throw(value_error,"this algorithm does not support constraints");
}
if (ec_size && m_only_ineq) {
pagmo_throw(value_error,"this algorithm does not support equality constraints");
}
const problem::base::size_type cont_size = problem.get_dimension() - problem.get_i_dimension();
if (!cont_size) {
pagmo_throw(value_error,"the problem has no continuous part");
}
// Do nothing if the population is empty.
if (!pop.size()) {
return;
}
// Extract the best individual and set the inital point
const population::size_type best_ind_idx = pop.get_best_idx();
const population::individual_type &best_ind = pop.get_individual(best_ind_idx);
// Structure to pass data to the objective function wrapper.
nlopt_wrapper_data data_objfun;
data_objfun.prob = &problem;
data_objfun.x.resize(problem.get_dimension());
data_objfun.dx.resize(problem.get_dimension());
data_objfun.f.resize(1);
// Structure to pass data to the constraint function wrapper.
std::vector<nlopt_wrapper_data> data_constrfun(boost::numeric_cast<std::vector<nlopt_wrapper_data>::size_type>(c_size));
for (problem::base::c_size_type i = 0; i < c_size; ++i) {
data_constrfun[i].prob = &problem;
data_constrfun[i].x.resize(problem.get_dimension());
data_constrfun[i].dx.resize(problem.get_dimension());
data_constrfun[i].c.resize(problem.get_c_dimension());
data_constrfun[i].c_comp = i;
}
// Main NLopt call.
nlopt::opt opt(m_algo, problem.get_dimension());
m_opt = opt;
// Sets local optimizer for aug_lag methods, do nothing otherwise
set_local(problem.get_dimension());
m_opt.set_lower_bounds(problem.get_lb());
m_opt.set_upper_bounds(problem.get_ub());
m_opt.set_min_objective(objfun_wrapper, &data_objfun);
for (problem::base::c_size_type i =0; i<ec_size; ++i) {
m_opt.add_equality_constraint(constraints_wrapper, &data_constrfun[i], problem.get_c_tol().at(i));
}
for (problem::base::c_size_type i =ec_size; i<c_size; ++i) {
m_opt.add_inequality_constraint(constraints_wrapper, &data_constrfun[i], problem.get_c_tol().at(i));
}
m_opt.set_ftol_abs(m_ftol);
m_opt.set_xtol_abs(m_xtol);
m_opt.set_maxeval(m_max_iter);
//nlopt::result result;
double dummy;
decision_vector x0(best_ind.cur_x);
m_opt.optimize(x0, dummy);
pop.set_x(best_ind_idx,x0);
}
示例11: evolve
/**
* Runs the Inverover algorithm for the number of generations specified in the constructor.
*
* @param[in,out] pop input/output pagmo::population to be evolved.
*/
void inverover::evolve(population &pop) const
{
const problem::tsp* prob;
//check if problem is of type pagmo::problem::tsp
try
{
const problem::tsp& tsp_prob = dynamic_cast<const problem::tsp &>(pop.problem());
prob = &tsp_prob;
}
catch (const std::bad_cast& e)
{
pagmo_throw(value_error,"Problem not of type pagmo::problem::tsp");
}
// Let's store some useful variables.
const population::size_type NP = pop.size();
const std::vector<std::vector<double> >& weights = prob->get_weights();
const problem::base::size_type Nv = prob->get_n_cities();
// Get out if there is nothing to do.
if (m_gen == 0) {
return;
}
// Initializing the random number generators
boost::uniform_real<double> uniform(0.0,1.0);
boost::variate_generator<boost::lagged_fibonacci607 &, boost::uniform_real<double> > unif_01(m_drng,uniform);
boost::uniform_int<int> NPless1(0, NP - 2);
boost::variate_generator<boost::mt19937 &, boost::uniform_int<int> > unif_NPless1(m_urng,NPless1);
boost::uniform_int<int> Nv_(0, Nv - 1);
boost::variate_generator<boost::mt19937 &, boost::uniform_int<int> > unif_Nv(m_urng,Nv_);
boost::uniform_int<int> Nvless1(0, Nv - 2);
boost::variate_generator<boost::mt19937 &, boost::uniform_int<int> > unif_Nvless1(m_urng,Nvless1);
//check if we have a symmetric problem (symmetric weight matrix)
bool is_sym = true;
for(size_t i = 0; i < Nv; i++)
{
for(size_t j = i+1; j < Nv; j++)
{
if(weights[i][j] != weights[j][i])
{
is_sym = false;
goto end_loop;
}
}
}
end_loop:
//create own local population
std::vector<decision_vector> my_pop(NP, decision_vector(Nv));
//check if some individuals in the population that is passed as a function input are feasible.
bool feasible;
std::vector<int> not_feasible;
for (size_t i = 0; i < NP; i++) {
feasible = prob->feasibility_x(pop.get_individual(i).cur_x);
if(feasible){ //if feasible store it in my_pop
switch( prob->get_encoding() ) {
case problem::tsp::FULL:
my_pop[i] = prob->full2cities(pop.get_individual(i).cur_x);
break;
case problem::tsp::RANDOMKEYS:
my_pop[i] = prob->randomkeys2cities(pop.get_individual(i).cur_x);
break;
case problem::tsp::CITIES:
my_pop[i] = pop.get_individual(i).cur_x;
break;
}
}
else
{
not_feasible.push_back(i);
}
}
//replace the not feasible individuals by feasible ones
int i;
switch (m_ini_type){
case 0:
{
//random initialization (produces feasible individuals)
for (size_t ii = 0; ii < not_feasible.size(); ii++) {
i = not_feasible[ii];
for (size_t j = 0; j < Nv; j++) {
my_pop[i][j] = j;
}
}
int tmp;
size_t rnd_idx;
for (size_t j = 1; j < Nv-1; j++) {
boost::uniform_int<int> dist_(j, Nv - 1);
//.........这里部分代码省略.........
示例12: fair_r_policy
// Selection implementation.
std::vector<std::pair<population::size_type,std::vector<population::individual_type>::size_type> >
hv_fair_r_policy::select(const std::vector<population::individual_type> &immigrants, const population &dest) const
{
// Fall back to fair_r_policy when facing a single-objective problem.
if (dest.problem().get_f_dimension() == 1) {
return fair_r_policy(m_rate, m_type).select(immigrants, dest);
}
std::vector<population::individual_type> filtered_immigrants;
filtered_immigrants.reserve(immigrants.size());
// Keeps information on the original indexing of immigrants after we filter out the duplicates
std::vector<unsigned int> original_immigrant_indices;
original_immigrant_indices.reserve(immigrants.size());
// Remove the duplicates from the set of immigrants
std::vector<population::individual_type>::iterator im_it = (const_cast<std::vector<population::individual_type> &>(immigrants)).begin();
unsigned int im_idx = 0;
for( ; im_it != immigrants.end() ; ++im_it) {
decision_vector im_x((*im_it).cur_x);
bool equal = true;
for ( unsigned int idx = 0 ; idx < dest.size() ; ++idx ) {
decision_vector isl_x(dest.get_individual(idx).cur_x);
equal = true;
for (unsigned int d_idx = 0 ; d_idx < im_x.size() ; ++d_idx) {
if (im_x[d_idx] != isl_x[d_idx]) {
equal = false;
break;
}
}
if (equal) {
break;
}
}
if (!equal) {
filtered_immigrants.push_back(*im_it);
original_immigrant_indices.push_back(im_idx);
}
++im_idx;
}
// Computes the number of immigrants to be selected (accounting for the destination pop size)
const population::size_type rate_limit = std::min<population::size_type>(get_n_individuals(dest), boost::numeric_cast<population::size_type>(filtered_immigrants.size()));
// Defines the retvalue
std::vector<std::pair<population::size_type, std::vector<population::individual_type>::size_type> > result;
// Skip the remaining computation if there's nothing to do
if (rate_limit == 0) {
return result;
}
// Makes a copy of the destination population
population pop_copy(dest);
// Merge the immigrants to the copy of the destination population
for (population::size_type i = 0; i < rate_limit; ++i) {
pop_copy.push_back(filtered_immigrants[i].cur_x);
}
// Population fronts stored as indices of individuals.
std::vector< std::vector<population::size_type> > fronts_i = pop_copy.compute_pareto_fronts();
// Population fronts stored as fitness vectors of individuals.
std::vector< std::vector<fitness_vector> > fronts_f (fronts_i.size());
// Nadir point is established manually later, first point is a first "safe" candidate.
fitness_vector refpoint(pop_copy.get_individual(0).cur_f);
// Fill fronts_f with fitness vectors and establish the nadir point
for (unsigned int f_idx = 0 ; f_idx < fronts_i.size() ; ++f_idx) {
fronts_f[f_idx].resize(fronts_i[f_idx].size());
for (unsigned int p_idx = 0 ; p_idx < fronts_i[f_idx].size() ; ++p_idx) {
fronts_f[f_idx][p_idx] = fitness_vector(pop_copy.get_individual(fronts_i[f_idx][p_idx]).cur_f);
// Update the nadir point manually for efficiency.
for (unsigned int d_idx = 0 ; d_idx < fronts_f[f_idx][p_idx].size() ; ++d_idx) {
refpoint[d_idx] = std::max(refpoint[d_idx], fronts_f[f_idx][p_idx][d_idx]);
}
}
}
// Epsilon is added to nadir point
for (unsigned int d_idx = 0 ; d_idx < refpoint.size() ; ++d_idx) {
refpoint[d_idx] += m_nadir_eps;
}
// Vector for maintaining the original indices of points for augmented population as 0 and 1
std::vector<unsigned int> g_orig_indices(pop_copy.size(), 1);
unsigned int no_discarded_immigrants = 0;
// Store which front we process (start with the last front) and the number of processed individuals.
unsigned int front_idx = fronts_i.size(); // front_idx is equal to the size, since it's decremented right in the main loop
unsigned int processed_individuals = 0;
// Pairs of (islander index, islander exclusive hypervolume)
// Second item is updated later
//.........这里部分代码省略.........
示例13: evolve
void bee_colony::evolve(population &pop) const
{
// Let's store some useful variables.
const problem::base &prob = pop.problem();
const problem::base::size_type prob_i_dimension = prob.get_i_dimension(), D = prob.get_dimension(), Dc = D - prob_i_dimension, prob_c_dimension = prob.get_c_dimension();
const decision_vector &lb = prob.get_lb(), &ub = prob.get_ub();
const population::size_type NP = (int) pop.size();
//We perform some checks to determine wether the problem/population are suitable for ABC
if ( Dc == 0 ) {
pagmo_throw(value_error,"There is no continuous part in the problem decision vector for ABC to optimise");
}
if ( prob.get_f_dimension() != 1 ) {
pagmo_throw(value_error,"The problem is not single objective and ABC is not suitable to solve it");
}
if ( prob_c_dimension != 0 ) {
pagmo_throw(value_error,"The problem is not box constrained and ABC is not suitable to solve it");
}
if (NP < 2) {
pagmo_throw(value_error,"for ABC at least 2 individuals in the population are needed");
}
// Get out if there is nothing to do.
if (m_iter == 0) {
return;
}
// Some vectors used during evolution are allocated here.
fitness_vector fnew(prob.get_f_dimension());
decision_vector dummy(D,0); //used for initialisation purposes
std::vector<decision_vector > X(NP,dummy); //set of food sources
std::vector<fitness_vector> fit(NP); //food sources fitness
decision_vector temp_solution(D,0);
std::vector<int> trial(NP,0);
std::vector<double> probability(NP);
population::size_type neighbour = 0;
decision_vector::size_type param2change = 0;
std::vector<double> selectionfitness(NP), cumsum(NP), cumsumTemp(NP);
std::vector <population::size_type> selection(NP);
double r = 0;
// Copy the food sources position and their fitness
for ( population::size_type i = 0; i<NP; i++ ) {
X[i] = pop.get_individual(i).cur_x;
fit[i] = pop.get_individual(i).cur_f;
}
// Main ABC loop
for (int j = 0; j < m_iter; ++j) {
//1- Send employed bees
for (population::size_type ii = 0; ii< NP; ++ii) {
//selects a random component (only of the continuous part) of the decision vector
param2change = boost::uniform_int<decision_vector::size_type>(0,Dc-1)(m_urng);
//randomly chose a solution to be used to produce a mutant solution of solution ii
//randomly selected solution must be different from ii
do{
neighbour = boost::uniform_int<population::size_type>(0,NP-1)(m_urng);
}
while(neighbour == ii);
//copy local solution into temp_solution (the whole decision_vector, also the integer part)
for(population::size_type i=0; i<D; ++i) {
temp_solution[i] = X[ii][i];
}
//mutate temp_solution
temp_solution[param2change] = X[ii][param2change] + boost::uniform_real<double>(-1,1)(m_drng) * (X[ii][param2change] - X[neighbour][param2change]);
//if generated parameter value is out of boundaries, it is shifted onto the boundaries*/
if (temp_solution[param2change]<lb[param2change]) {
temp_solution[param2change] = lb[param2change];
}
if (temp_solution[param2change]>ub[param2change]) {
temp_solution[param2change] = ub[param2change];
}
//Calling void prob.objfun(fitness_vector,decision_vector) is more efficient as no memory allocation occur
//A call to fitness_vector prob.objfun(decision_vector) allocates memory for the return value.
prob.objfun(fnew,temp_solution);
//If the new solution is better than the old one replace it with the mutant one and reset its trial counter
if(prob.compare_fitness(fnew, fit[ii])) {
X[ii][param2change] = temp_solution[param2change];
pop.set_x(ii,X[ii]);
prob.objfun(fit[ii], X[ii]); //update the fitness vector
trial[ii] = 0;
}
else {
trial[ii]++; //if the solution can't be improved incrase its trial counter
}
//.........这里部分代码省略.........
示例14: evolve
/**
* Run the CORE algorithm
*
* @param[in,out] pop input/output pagmo::population to be evolved.
*/
void cstrs_core::evolve(population &pop) const
{
// store useful variables
const problem::base &prob = pop.problem();
const population::size_type pop_size = pop.size();
const problem::base::size_type prob_dimension = prob.get_dimension();
// get the constraints dimension
problem::base::c_size_type prob_c_dimension = prob.get_c_dimension();
//We perform some checks to determine wether the problem/population are suitable for CORE
if(prob_c_dimension < 1) {
pagmo_throw(value_error,"The problem is not constrained and CORE is not suitable to solve it");
}
if(prob.get_f_dimension() != 1) {
pagmo_throw(value_error,"The problem is multiobjective and CORE is not suitable to solve it");
}
// Get out if there is nothing to do.
if(pop_size == 0) {
return;
}
// generates the unconstrained problem
problem::con2uncon prob_unconstrained(prob);
// associates the population to this problem
population pop_uncon(prob_unconstrained);
// fill this unconstrained population
pop_uncon.clear();
for(population::size_type i=0; i<pop_size; i++) {
pop_uncon.push_back(pop.get_individual(i).cur_x);
}
// vector containing the infeasibles positions
std::vector<population::size_type> pop_infeasibles;
// Main CORE loop
for(int k=0; k<m_gen; k++) {
if(k%m_repair_frequency == 0) {
pop_infeasibles.clear();
// get the infeasible individuals
for(population::size_type i=0; i<pop_size; i++) {
if(!prob.feasibility_c(pop.get_individual(i).cur_c)) {
pop_infeasibles.push_back(i);
}
}
// random shuffle of infeasibles?
population::size_type number_of_repair = (population::size_type)(m_repair_ratio * pop_infeasibles.size());
// repair the infeasible individuals
for(population::size_type i=0; i<number_of_repair; i++) {
const population::size_type ¤t_individual_idx = pop_infeasibles.at(i);
pop.repair(current_individual_idx, m_repair_algo);
}
// the population is repaired, it can be now used in the new unconstrained population
// only the repaired individuals are put back in the population
for(population::size_type i=0; i<number_of_repair; i++) {
population::size_type current_individual_idx = pop_infeasibles.at(i);
pop_uncon.set_x(current_individual_idx, pop.get_individual(current_individual_idx).cur_x);
}
}
m_original_algo->evolve(pop_uncon);
// push back the population in the main problem
pop.clear();
for(population::size_type i=0; i<pop_size; i++) {
pop.push_back(pop_uncon.get_individual(i).cur_x);
}
// Check the exit conditions (every 40 generations, just as DE)
if(k % 40 == 0) {
decision_vector tmp(prob_dimension);
double dx = 0;
for(decision_vector::size_type i=0; i<prob_dimension; i++) {
tmp[i] = pop.get_individual(pop.get_worst_idx()).best_x[i] - pop.get_individual(pop.get_best_idx()).best_x[i];
dx += std::fabs(tmp[i]);
}
if(dx < m_xtol ) {
if (m_screen_output) {
std::cout << "Exit condition -- xtol < " << m_xtol << std::endl;
}
break;
}
double mah = std::fabs(pop.get_individual(pop.get_worst_idx()).best_f[0] - pop.get_individual(pop.get_best_idx()).best_f[0]);
//.........这里部分代码省略.........
示例15: evolve
void cs::evolve(population &pop) const
{
// Let's store some useful variables.
const problem::base &prob = pop.problem();
const problem::base::size_type D = prob.get_dimension(), prob_i_dimension = prob.get_i_dimension(), prob_c_dimension = prob.get_c_dimension(), prob_f_dimension = prob.get_f_dimension();
const decision_vector &lb = prob.get_lb(), &ub = prob.get_ub();
const population::size_type NP = pop.size();
const problem::base::size_type Dc = D - prob_i_dimension;
//We perform some checks to determine whether the problem/population are suitable for compass search
if ( Dc == 0 ) {
pagmo_throw(value_error,"There is no continuous part in the problem decision vector for compass search to optimise");
}
if ( prob_c_dimension != 0 ) {
pagmo_throw(value_error,"The problem is not box constrained and compass search is not suitable to solve it");
}
if ( prob_f_dimension != 1 ) {
pagmo_throw(value_error,"The problem is not single objective and compass search is not suitable to solve it");
}
// Get out if there is nothing to do.
if (NP == 0 || m_max_eval == 0) {
return;
}
//Starting point is the best individual
const int bestidx = pop.get_best_idx();
const decision_vector &x0 = pop.get_individual(bestidx).cur_x;
const fitness_vector &fit0 = pop.get_individual(bestidx).cur_f;
decision_vector x=x0,newx;
fitness_vector f=fit0,newf=fit0;
bool flag = false;
int eval=0;
double newrange=m_start_range;
while (newrange > m_stop_range && eval <= m_max_eval) {
flag = false;
for (unsigned int i=0; i<Dc; i++) {
newx=x;
//move up
newx[i] = x[i] + newrange * (ub[i]-lb[i]);
//feasibility correction
if (newx[i] > ub [i]) newx[i]=ub[i];
prob.objfun(newf,newx); eval++;
if (prob.compare_fitness(newf,f)) {
f = newf;
x = newx;
flag=true;
break; //accept
}
//move down
newx[i] = x[i] - newrange * (ub[i]-lb[i]);
//feasibility correction
if (newx[i] < lb [i]) newx[i]=lb[i];
prob.objfun(newf,newx); eval++;
if (prob.compare_fitness(newf,f)) { //accept
f = newf;
x = newx;
flag=true;
break;
}
}
if (!flag) {
newrange *= m_reduction_coeff;
}
} //end while
std::transform(x.begin(), x.end(), pop.get_individual(bestidx).cur_x.begin(), newx.begin(),std::minus<double>()); // newx is now velocity
pop.set_x(bestidx,x); //new evaluation is possible here......
pop.set_v(bestidx,newx);
}