SwapMutation.h

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#ifndef DIGNEA_SWAPMUTATION_H
#define DIGNEA_SWAPMUTATION_H
 
#include <dignea/core/Mutation.h>
#include <dignea/utilities/random/PseudoRandom.h>
 
#include <nlohmann/json.hpp>
 
using json = nlohmann::json;
 
template <class S>
class SwapMutation : public Mutation<S> {
   public:
    SwapMutation() = default;
 
    virtual ~SwapMutation() = default;
 
    void run(S &ind, const double &probability, Problem<S> *) override;
 
    std::string getName() const override { return "Swap Mutation"; };
};
 
template <class S>
void SwapMutation<S>::run(S &ind, const double &probability,
                          Problem<S> *problem) {
    int idx2Swap = 0;
    int idx2Swap2 = 0;
    while ((idx2Swap == idx2Swap2)) {
        // Cannot change first and last element
        // -2 to skip the last element too
        idx2Swap = PseudoRandom::randInt(1, ind.getNumberOfVars() - 2);
        idx2Swap2 = PseudoRandom::randInt(1, ind.getNumberOfVars() - 2);
    }
    try {
        auto iGene = ind.getVarAt(idx2Swap);
        auto iGene2 = ind.getVarAt(idx2Swap2);
        ind.setVarAt(idx2Swap, iGene2);
        ind.setVarAt(idx2Swap2, iGene);
    } catch (OutOfRange const &err) {
        auto j = ind.to_json();
        std::string msg = std::string(err.what()) +
                          " from SwapMutation operator with idx1: " +
                          to_string(idx2Swap).c_str() +
                          " and idx2: " + to_string(idx2Swap2).c_str() +
                          " with ind.getNumberOfVars() = " +
                          to_string(ind.getNumberOfVars()) +
                          "\n Individual is: \n" + j.dump(4);
        std::cout << msg << std::endl;
        exit(1);
    }
}
 
#endif  // DIGNEA_SWAPMUTATION_H