// Sends employed Bees
void SendEmployedBees(
double & GlobalMin,
NumericVector & GlobalParams,
NumericVector & fitness,
NumericVector & f,
IntegerVector & trial,
Function & fun,
NumericMatrix & Foods,
const NumericVector & lb,
const NumericVector & ub
) {
int param2change, neighbour;
double ObjValSol, FitnessSol;
NumericVector solution(Foods.ncol());
for (int i=0;i<Foods.nrow();i++) {
// Random parameter to change
param2change = (int)(unif_rand()*Foods.ncol());
// Random neighbour to select
neighbour = i;
while (neighbour == i)
neighbour = (int)(unif_rand()*Foods.nrow());
// Suggesting new solution
solution = Foods(i,_);
solution[param2change] = Foods(i,param2change) +
(Foods(i, param2change) - Foods(neighbour, param2change))*(unif_rand()-.5)*2;
// Truncating
if (solution[param2change] < lb.at(param2change))
solution[param2change] = lb.at(param2change);
if (solution[param2change] > ub.at(param2change))
solution[param2change] = ub.at(param2change);
// Comparing current solution with new one
ObjValSol = as<double>(fun(solution));
FitnessSol = CalculateFitness(ObjValSol);
if (FitnessSol > fitness[i]) {
Foods(i,_) = solution;
fitness[i] = FitnessSol;
f[i] = ObjValSol;
trial[i] = 0;
} else {
trial[i]+=1;
}
}
return;
}
// Initializes a food source
void init(
int index,
NumericVector & fitness,
NumericVector & f,
IntegerVector & trial,
Function & fun,
NumericMatrix & Foods,
const NumericVector & lb,
const NumericVector & ub
) {
for (int j=0; j<lb.size(); j++)
Foods.at(index,j) = runif(1, lb.at(j), ub.at(j))[0];
f[index] = as<double>(fun(Foods(index,_)));
fitness[index] = CalculateFitness(f[index]);
trial[index] = 0;
return;
}
// [[Rcpp::export(name=".abc_cpp")]]
List abc_cpp(
NumericVector & par,
Function & fn,
const NumericVector & lb,
const NumericVector & ub,
int FoodNumber = 20,
int limit = 100,
int maxCycle = 1000,
int criter = 50 // , double tol=1e-10
) {
// Initialize:
NumericMatrix Foods(FoodNumber, par.size());
NumericVector f(FoodNumber), fitness(FoodNumber), prob(FoodNumber);
IntegerVector trial(FoodNumber);
NumericMatrix ans(maxCycle, par.size());
// Initializing
NumericVector GlobalParams = clone(par);
double GlobalMin = as<double>(fn(GlobalParams));
// Should be distributed equally
for (int i=0;i<FoodNumber;i++) {
for (int j=0;j<par.size();j++)
Foods.at(i,j) = lb.at(j) + (ub.at(j) - lb.at(j))/(FoodNumber-1.0)*i;
// Checking if it is defined
f[i] = as<double>(fn(Foods(i,_)));
if (NumericVector::is_na(f[i]))
stop("Undefined value for -fn-. Check the function's domain.");
fitness[i] = CalculateFitness(f[i]);
trial[i] = 0;
}
int unchanged = 0;
MemorizeBetsSource(GlobalMin, GlobalParams, f, Foods, unchanged);
ans(0,_) = GlobalParams;
unchanged = 0;
// double OldGlobalMin = GlobalMin;
int i=0;
while (++i<maxCycle) {
SendEmployedBees(GlobalMin, GlobalParams, fitness, f, trial, fn, Foods, lb, ub);
CalculateProbabilities(Foods, fitness, prob);
SendOnlookerBees(GlobalMin, GlobalParams, fitness, f, trial, prob, fn, Foods, lb, ub);
MemorizeBetsSource(GlobalMin, GlobalParams, f, Foods, unchanged);
// Storing and breaking
ans(i,_) = GlobalParams;
if (unchanged>=criter) break;
// If not, then send them out again
SendScoutBees(fitness, f, trial, prob, fn, Foods, lb, ub, limit);
}
return List::create(
_["Foods"] = Foods,
_["f"] = f,
_["fitness"]= fitness,
_["trial"] = trial,
_["value"] = GlobalMin,
_["par"] = GlobalParams,
_["counts"] = i,
_["hist"] = ans(Range(0,i),_)
);
}
