[REFACTOR] initialization of BlockForestDomain

moved initialization of BlockForestDomain into refresh function
This way the BlockForestDomain can be refreshed (e.g. as part of
the load balancing) without recreating it.

src/mesa_pd/domain/BlockForestDomain.cpp

@@ -32,6 +32,12 @@ namespace domain {
 /// \post neighborSubdomains_ is sorted by rank
 BlockForestDomain::BlockForestDomain(const std::shared_ptr<blockforest::BlockForest>& blockForest)
    : blockForest_(blockForest)
+{
+   refresh();
+}
+
+/// \post neighborSubdomains_ is sorted by rank
+void BlockForestDomain::refresh()
 {
    ownRank_ = mpi::MPIManager::instance()->rank();
 
@@ -41,6 +47,9 @@ BlockForestDomain::BlockForestDomain(const std::shared_ptr<blockforest::BlockFor
 
    if (blockForest_->empty()) return;
 
+   localAABBs_.clear();
+   neighborSubdomains_.clear();
+   neighborProcesses_.clear();
    unionOfLocalAABBs_ = blockForest_->begin()->getAABB();
    for (auto& iBlk : *blockForest_)
    {

src/mesa_pd/domain/BlockForestDomain.h

@@ -35,6 +35,14 @@ class BlockForestDomain : public IDomain
 public:
    BlockForestDomain(const std::shared_ptr<blockforest::BlockForest>& blockForest);
 
+   /**
+    * @brief If the BlockForest is changed this function has to be called in order to
+    * update all interal caches!
+    *
+    * Updates the local caches for local and neighbor AABBs.
+    */
+   void refresh();
+
    bool   isContainedInProcessSubdomain(const uint_t rank, const Vec3& pt) const override;
    bool   isContainedInLocalSubdomain(const Vec3& pt, const real_t& radius) const override;
    /// Is the sphere defined by \p pt and \p radius completely inside the local subdomin?
@@ -48,6 +56,7 @@ public:
    bool   intersectsWithProcessSubdomain(const uint_t rank, const Vec3& pt, const real_t& radius) const override;
    void   correctParticlePosition(Vec3& pt) const override;
 
+   const math::AABB& getUnionOfLocalAABBs() const {return unionOfLocalAABBs_;}
    size_t getNumLocalAABBs() const {return localAABBs_.size();}
    size_t getNumNeighborSubdomains() const {return neighborSubdomains_.size();}
    size_t getNumNeighborProcesses() const {return neighborProcesses_.size();}