[constraints] implement constraints matrix

frackit/entitynetwork/CMakeLists.txt

 install(FILES
 constraints.hh
+constraintsmatrix.hh
 containedentitynetwork.hh
 containedentitynetworkinterface.hh
 entitynetwork.hh

frackit/entitynetwork/constraintsmatrix.hh

+// -*- mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+// vi: set et ts=4 sw=4 sts=4:
+/*****************************************************************************
+ *   See the file COPYING for full copying permissions.                      *
+ *                                                                           *
+ *   This program is free software: you can redistribute it and/or modify    *
+ *   it under the terms of the GNU General Public License as published by    *
+ *   the Free Software Foundation, either version 2 of the License, or       *
+ *   (at your option) any later version.                                     *
+ *                                                                           *
+ *   This program is distributed in the hope that it will be useful,         *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of          *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the            *
+ *   GNU General Public License for more details.                            *
+ *                                                                           *
+ *   You should have received a copy of the GNU General Public License       *
+ *   along with this program.  If not, see <http://www.gnu.org/licenses/>.   *
+ *****************************************************************************/
+/*!
+ * \file
+ * \brief Class that allows defining a matrix of constraints.
+ *        This is useful in contexts where multiple entity sets
+ *        are defined, and where different constraints should be
+ *        fulfilled for different pairs of entity sets.
+ */
+#ifndef FRACKIT_ENTITYNETWORK_CONSTRAINTS_MATRIX_HH
+#define FRACKIT_ENTITYNETWORK_CONSTRAINTS_MATRIX_HH
+
+#include <stdexcept>
+#include <utility>
+#include <vector>
+#include <unordered_map>
+#include <initializer_list>
+
+#include <frackit/common/id.hh>
+#include <frackit/common/idpair.hh>
+
+namespace Frackit {
+
+/*!
+ * \brief Class that allows defining a matrix of constraints.
+ *        For each constraint that is defined, a list of id pairs
+ *        is passed that defines between which ids (representing
+ *        the ids of the corresponding entity sets) the constraints
+ *        should hold.
+ */
+template<class C>
+class EntityNetworkConstraintsMatrix
+{
+    using IndexSet = std::vector<std::size_t>;
+    using IndexPair = std::pair<std::size_t, std::size_t>;
+    using IndexPairVector = std::vector<IndexPair>;
+
+public:
+    //! export underlying constraints type
+    using Constraints = C;
+
+    /*!
+     * \brief Add a constraint that should be fulfilled
+     *        between the two entity sets defined in the
+     *        provided id pair.
+     */
+    void addConstraints(const Constraints& c, const IdPair& idPair)
+    {
+        addConstraint_(c);
+        updateIndexMaps_(idPair);
+    }
+
+    /*!
+     * \brief Add a constraint that should be fulfilled
+     *        between all pairs of entity sets defined
+     *        in the provided list of id pairs.
+     */
+    void addConstraints(const Constraints& c,
+                        const std::initializer_list<IdPair>& idPairs)
+    {
+        addConstraint_(c);
+        for (const auto& idPair : idPairs)
+            updateIndexMaps_(idPair);
+    }
+
+    /*!
+     * \brief Evaluate if an entity fulfills all constraints.
+     * \param entitySets The class containing all entity sets.
+     * \param entity The entity to be checked.
+     * \param id The id of the entity set to which the entity belongs.
+     */
+    template<class EntitySets, class Entity>
+    bool evaluate(const EntitySets& entitySets,
+                  const Entity& entity,
+                  const Id& id)
+    {
+        auto it = constraintsIndexMap_.find(id.get());
+        if (it == constraintsIndexMap_.end())
+            throw std::runtime_error("evaluate: no constraints set for given id");
+
+        for (const auto& idxPair : it->second)
+        {
+            const auto otherId = Id(idxPair.first);
+            const auto& constraints = constraints_[idxPair.second];
+
+            // lambda for the evaluation of the constraints
+            bool isAdmissible;
+            auto evalConstraintOnSet = [&] (const auto& entitySet) -> void
+            { isAdmissible = constraints.evaluate(entitySet, entity); };
+
+            // applyOnSet() returns false if lambda was not applied
+            // This is the case e.g. when the set is empty. Here,
+            // return false only if applyOnSet() was successful.
+            if (entitySets.applyOnSet(otherId, evalConstraintOnSet))
+                if (!isAdmissible)
+                    return false;
+        }
+
+        return true;
+    }
+
+private:
+    /*!
+     * \brief Adds a constraints instance to the container.
+     */
+    void addConstraint_(const Constraints& c)
+    {
+        constraints_.push_back(c);
+    }
+
+    /*!
+     * \brief Updates the index maps after a call to addConstraint_().
+     */
+    void updateIndexMaps_(const IdPair& idPair)
+    {
+        const auto firstIdx = idPair.first().get();
+        const auto secondIdx = idPair.second().get();
+
+        auto it = relations_.find(idPair.first().get());
+        if (it != relations_.end())
+            if (std::count(it->second.begin(),
+                           it->second.end(),
+                           idPair.second().get()))
+                throw std::runtime_error("ConstraintsMatrix: Relation was already defined!");
+
+        const auto cIdx = constraints_.size() - 1;
+        constraintsIndexMap_[firstIdx].push_back(std::make_pair(secondIdx, cIdx));
+        relations_[firstIdx].push_back(secondIdx);
+    }
+
+    //! stores all constraints
+    std::vector<Constraints> constraints_;
+    //! maps to each binary relation the index of the constraints
+    std::unordered_map<std::size_t, IndexPairVector> constraintsIndexMap_;
+    //! stores to each id with which other ids a relation was defined
+    std::unordered_map<std::size_t, IndexSet> relations_;
+};
+
+} // end namespace Frackit
+
+#endif // FRACKIT_ENTITYNETWORK_CONSTRAINTS_HH