blp_no_edge_labels.ipp

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/***************************************************************************
 *                                                                          *
 *   Copyright (C) 2018 by David B. Blumenthal                              *
 *                                                                          *
 *   This file is part of GEDLIB.                                           *
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 *   GEDLIB is free software: you can redistribute it and/or modify it      *
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 *   (at your option) any later version.                                    *
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 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the           *
 *   GNU Lesser General Public License for more details.                    *
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#ifndef SRC_METHODS_BLP_NO_EDGE_LABELS_IPP_
#define SRC_METHODS_BLP_NO_EDGE_LABELS_IPP_


namespace ged {

template<class UserNodeLabel, class UserEdgeLabel>
BLPNoEdgeLabels<UserNodeLabel, UserEdgeLabel>::
~BLPNoEdgeLabels() {}

template<class UserNodeLabel, class UserEdgeLabel>
BLPNoEdgeLabels<UserNodeLabel, UserEdgeLabel>::
BLPNoEdgeLabels(const GEDData<UserNodeLabel, UserEdgeLabel> & ged_data) :
MIPBasedMethod<UserNodeLabel, UserEdgeLabel>(ged_data),
x_(),
s_(),
t_() {}

template<class UserNodeLabel, class UserEdgeLabel>
void
BLPNoEdgeLabels<UserNodeLabel, UserEdgeLabel>::
mip_populate_model_(const GEDGraph & g, const GEDGraph & h, GRBModel & model) {

    // Clear the variables and the constant for the objective.
    x_.clear();
    s_.clear();
    t_.clear();

    // Determine minimal edge deletion or insertion cost.
    double min_edge_ins_del_cost{std::min(this->ged_data_.min_edge_del_cost(g), this->ged_data_.min_edge_ins_cost(h))};

    // Determine N.
    std::size_t N{g.num_nodes() + h.num_nodes()};

    // Add substitution variables to the model.
    NodeMap::Assignment key;
    for (GEDGraph::GraphID i{0}; i < N; i++) {
        for (GEDGraph::GraphID k{0}; k < N; k++) {
            key.first = i;
            key.second = k;
            if ((i == 0) and (k == 0) and this->map_root_to_root_) {
                x_[key] = model.addVar(1, 1, this->ged_data_.node_cost(g.get_node_label(i), h.get_node_label(k)), variable_type_());
            }
            else if ((i < g.num_nodes()) and (k < h.num_nodes())) {
                x_[key] = model.addVar(0, 1, this->ged_data_.node_cost(g.get_node_label(i), h.get_node_label(k)), variable_type_());
            }
            else if (i < g.num_nodes()) {
                x_[key] = model.addVar(0, 1, this->ged_data_.node_cost(g.get_node_label(i), dummy_label()), variable_type_());
            }
            else if (k < h.num_nodes()) {
                x_[key] = model.addVar(0, 1, this->ged_data_.node_cost(dummy_label(), h.get_node_label(k)), variable_type_());
            }
            else {
                x_[key] = model.addVar(0, 1, 0, variable_type_());
            }
            s_[key] = model.addVar(0, 1, min_edge_ins_del_cost / 2, variable_type_());
            t_[key] = model.addVar(0, 1, min_edge_ins_del_cost / 2, variable_type_());
        }
    }

    // Add node constraints to the model.
    GRBLinExpr lhs;
    for (GEDGraph::GraphID i{0}; i < N; i++) {
        key.first = i;
        lhs = 0;
        for (GEDGraph::GraphID k{0}; k < N; k++) {
            key.second = k;
            lhs += x_.at(key);
        }
        model.addConstr(lhs, GRB_EQUAL, 1);
    }
    for (GEDGraph::GraphID k{0}; k < N; k++) {
        key.second = k;
        lhs = 0;
        for (GEDGraph::GraphID i{0}; i < N; i++) {
            key.first = i;
            lhs += x_.at(key);
        }
        model.addConstr(lhs, GRB_EQUAL, 1);
    }

    // Add topology constraints to the model.
    for (GEDGraph::GraphID i{0}; i < N; i++) {
        for (GEDGraph::GraphID k{0}; k < N; k++) {
            key.first = i;
            key.second = k;
            lhs = s_.at(key) - t_.at(key);
            if (i < g.num_nodes()) {
                for (auto ij = g.incident_edges(i).first; ij != g.incident_edges(i).second; ij++) {
                    key.first = g.head(*ij);
                    lhs += x_.at(key);
                }
            }
            if (k < h.num_nodes()) {
                key.first = i;
                for (auto kl = h.incident_edges(k).first; kl != h.incident_edges(k).second; kl++) {
                    key.second = h.head(*kl);
                    lhs -= x_.at(key);
                }
            }
            model.addConstr(lhs, GRB_EQUAL, 0);
        }
    }


}

template<class UserNodeLabel, class UserEdgeLabel>
void
BLPNoEdgeLabels<UserNodeLabel, UserEdgeLabel>::
mip_model_to_node_map_(const GEDGraph & g, const GEDGraph & h, GRBModel & model, NodeMap & node_map) {

    // Initialize local variables.
    std::vector<bool> delete_node(g.num_nodes(), true);
    std::vector<bool> insert_node(h.num_nodes(), true);
    GEDGraph::NodeID i, k;

    // Add node substitutions.
    for (auto it = x_.begin(); it != x_.end(); it++) {
        i = it->first.first;
        k = it->first.second;
        if ((i < g.num_nodes()) and (k < h.num_nodes()) and (it->second.get(GRB_DoubleAttr_X) > 0)) {
            node_map.add_assignment(i, k);
            delete_node[i] = false;
            insert_node[k] = false;
        }
    }

    // Add node deletions.
    for (i = 0; i < g.num_nodes(); i++) {
        if (delete_node.at(i)) {
            node_map.add_assignment(i, GEDGraph::dummy_node());
        }
    }

    // Add node insertions.
    for (k = 0; k < h.num_nodes(); k++) {
        if (insert_node.at(k)) {
            node_map.add_assignment(GEDGraph::dummy_node(), k);
        }
    }

    // Set induced cost.
    this->ged_data_.compute_induced_cost(g, h, node_map);

}

template<class UserNodeLabel, class UserEdgeLabel>
bool
BLPNoEdgeLabels<UserNodeLabel, UserEdgeLabel>::
mip_model_to_lsape_projection_problem_(const GEDGraph & g, const GEDGraph & h, GRBModel & model, DMatrix & lsape_instance) {
    GEDGraph::NodeID i, k;
    for (auto it = x_.begin(); it != x_.end(); it++) {
        i = std::min(it->first.first, g.num_nodes());
        k = std::min(it->first.second, h.num_nodes());
        lsape_instance(i, k) -= it->second.get(GRB_DoubleAttr_X);
    }
    return true;
}

template<class UserNodeLabel, class UserEdgeLabel>
char
BLPNoEdgeLabels<UserNodeLabel, UserEdgeLabel>::
variable_type_() const {
    if (this->relax_) {
        return GRB_CONTINUOUS;
    }
    return GRB_BINARY;
}

}


#endif /* SRC_METHODS_BLP_NO_EDGE_LABELS_IPP_ */