CGraphSlamEngine_MR_impl.h

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/* +---------------------------------------------------------------------------+
                                 |                     Mobile Robot Programming Toolkit (MRPT) |
   | http://www.mrpt.org/                             | | | | Copyright (c)
   2005-2016, Individual contributors, see AUTHORS file        | | See:
   http://www.mrpt.org/Authors - All rights reserved.                   | |
   Released under BSD License. See details in http://www.mrpt.org/License    |
                                 +---------------------------------------------------------------------------+
 */

#pragma once

#include <chrono>
#include <thread>
#include <mrpt_msgs/GetCMGraph.h>
#include <mrpt_msgs_bridge/network_of_poses.h>
#include <mrpt/ros1bridge/pose.h>

#include <mrpt/math/CMatrixFixed.h>
namespace mrpt::math
{
// backwards compatible
template <typename T, std::size_t ROWS, std::size_t COLS>
using CMatrixFixedNumeric = CMatrixFixed<T, ROWS, COLS>;
}  // namespace mrpt::math

namespace mrpt
{
namespace graphslam
{
template <class GRAPH_T>
CGraphSlamEngine_MR<GRAPH_T>::CGraphSlamEngine_MR(
        ros::NodeHandle* nh, const std::string& config_file,
        const std::string& rawlog_fname /* ="" */,
        const std::string& fname_GT /* ="" */,
        mrpt::graphslam::CWindowManager* win_manager /* = NULL */,
        mrpt::graphslam::deciders::CNodeRegistrationDecider<GRAPH_T>*
                node_reg /* = NULL */,
        mrpt::graphslam::deciders::CEdgeRegistrationDecider<GRAPH_T>*
                edge_reg /* = NULL */,
        mrpt::graphslam::optimizers::CGraphSlamOptimizer<GRAPH_T>*
                optimizer /* = NULL */)
        : parent_t::CGraphSlamEngine_ROS(
                  nh, config_file, rawlog_fname, fname_GT, win_manager, node_reg,
                  edge_reg, optimizer),
          m_conn_manager(dynamic_cast<mrpt::system::COutputLogger*>(this), nh),
          m_nh(nh),
          m_graph_nodes_last_size(0),
          m_registered_multiple_nodes(false),
          cm_graph_async_spinner(/* threads_num: */ 1, &this->custom_service_queue),
          m_sec_alignment_params("AlignmentParameters"),
          m_sec_mr_slam_params("MultiRobotParameters"),
          m_opts(*this)
{
        this->initClass();
}

template <class GRAPH_T>
CGraphSlamEngine_MR<GRAPH_T>::~CGraphSlamEngine_MR()
{
        MRPT_LOG_DEBUG_STREAM(
                "In Destructor: Deleting CGraphSlamEngine_MR instance...");
        cm_graph_async_spinner.stop();

        for (typename neighbors_t::iterator neighbors_it = m_neighbors.begin();
                 neighbors_it != m_neighbors.end(); ++neighbors_it)
        {
                delete *neighbors_it;
        }
}

template <class GRAPH_T>
bool CGraphSlamEngine_MR<GRAPH_T>::addNodeBatchesFromAllNeighbors()
{
        MRPT_START;
        using namespace mrpt::graphslam::detail;

        bool ret_val = false;
        for (const auto& neighbor : m_neighbors)
        {
                if (!isEssentiallyZero(
                                neighbor
                                        ->tf_self_to_neighbor_first_integrated_pose) &&  // inter-graph
                                                                                                                                         // TF found
                        neighbor->hasNewData() &&
                        neighbor->hasNewNodesBatch(m_opts.nodes_integration_batch_size))
                {
                        bool loc_ret_val = this->addNodeBatchFromNeighbor(neighbor);
                        if (loc_ret_val)
                        {
                                ret_val = true;
                        }
                }
        }

        return ret_val;
        MRPT_END;
}  // end of addNodeBatchesFromAllNeighbors

template <class GRAPH_T>
bool CGraphSlamEngine_MR<GRAPH_T>::addNodeBatchFromNeighbor(
        TNeighborAgentProps* neighbor)
{
        MRPT_START;
        ASSERT_(neighbor);
        using namespace mrpt::poses;
        using namespace mrpt::math;
        using namespace std;

        std::vector<TNodeID> nodeIDs;
        std::map<TNodeID, node_props_t> nodes_params;
        neighbor->getCachedNodes(&nodeIDs, &nodes_params, /*only unused=*/true);

        //
        // get the condensed measurements graph of the new nodeIDs
        //
        mrpt_msgs::GetCMGraph cm_graph_srv;
        // mrpt_msgs::GetCMGraphRequest::_nodeIDs_type& cm_graph_nodes =
        // cm_graph_srv.request.node_ids;
        for (const auto n : nodeIDs)
        {
                cm_graph_srv.request.node_ids.push_back(n);
        }

        MRPT_LOG_DEBUG_STREAM("Asking for the graph.");
        bool res = neighbor->cm_graph_srvclient.call(cm_graph_srv);      // blocking
        if (!res)
        {
                MRPT_LOG_ERROR_STREAM("Service call for CM_Graph failed.");
                return false;  // skip this if failed to fetch other's graph
        }
        MRPT_LOG_DEBUG_STREAM("Fetched graph successfully.");
        MRPT_LOG_DEBUG_STREAM(cm_graph_srv.response.cm_graph);

        GRAPH_T other_graph;
        mrpt_msgs_bridge::fromROS(cm_graph_srv.response.cm_graph, other_graph);

        //
        // merge batch of nodes in own graph
        //
        MRPT_LOG_WARN_STREAM(
                "Merging new batch from \""
                << neighbor->getAgentNs() << "\"..." << endl
                << "Batch: " << getSTLContainerAsString(cm_graph_srv.request.node_ids));
        hypots_t graph_conns;
        // build a hypothesis connecting the new batch with the last integrated
        // pose of the neighbor
        {
                pair<TNodeID, node_props_t> node_props_to_connect =
                        *nodes_params.begin();

                hypot_t graph_conn;
                constraint_t c;
                c.mean = node_props_to_connect.second.pose -
                                 neighbor->last_integrated_pair_neighbor_frame.second;
                c.cov_inv.setIdentity();
                graph_conn.setEdge(c);

                graph_conn.from = INVALID_NODEID;
                // get the nodeID of the last integrated neighbor node after remapping
                // in own graph numbering
                for (const auto n : this->m_graph.nodes)
                {
                        if (n.second.agent_ID_str == neighbor->getAgentNs() &&
                                n.second.nodeID_loc ==
                                        neighbor->last_integrated_pair_neighbor_frame.first)
                        {
                                graph_conn.from = n.first;
                                break;
                        }
                }
                ASSERT_(graph_conn.from != INVALID_NODEID);
                graph_conn.to = node_props_to_connect.first;  // other

                MRPT_LOG_DEBUG_STREAM(
                        "Hypothesis for adding the batch of nodes: " << graph_conn);
                graph_conns.push_back(graph_conn);
        }

        std::map<TNodeID, TNodeID> old_to_new_mappings;
        this->m_graph.mergeGraph(
                other_graph, graph_conns,
                /*hypots_from_other_to_self=*/false, &old_to_new_mappings);

        //
        // Mark Nodes/LaserScans as integrated
        //
        MRPT_LOG_WARN_STREAM("Marking used nodes as integrated - Integrating LSs");
        nodes_to_scans2D_t new_nodeIDs_to_scans_pairs;
        for (typename std::vector<TNodeID>::const_iterator n_cit = nodeIDs.begin();
                 n_cit != nodeIDs.end(); ++n_cit)
        {
                // Mark the neighbor's used nodes as integrated
                neighbor->nodeID_to_is_integrated.at(*n_cit) = true;

                // Integrate LaserScans at the newly integrated nodeIDs in own
                // nodes_to_laser_scans2D map
                new_nodeIDs_to_scans_pairs.insert(make_pair(
                        old_to_new_mappings.at(*n_cit), nodes_params.at(*n_cit).scan));
                MRPT_LOG_INFO_STREAM(
                        "Adding nodeID-LS of nodeID: "
                        << "\t[old:] " << *n_cit << endl
                        << "| [new:] " << old_to_new_mappings.at(*n_cit));
        }

        this->m_nodes_to_laser_scans2D.insert(
                new_nodeIDs_to_scans_pairs.begin(), new_nodeIDs_to_scans_pairs.end());
        edge_reg_mr_t* edge_reg_mr = dynamic_cast<edge_reg_mr_t*>(this->m_edge_reg);
        edge_reg_mr->addBatchOfNodeIDsAndScans(new_nodeIDs_to_scans_pairs);

        this->execDijkstraNodesEstimation();
        neighbor->resetFlags();

        // keep track of the last integrated nodeID
        {
                TNodeID last_node = *nodeIDs.rbegin();
                neighbor->last_integrated_pair_neighbor_frame =
                        make_pair(last_node, nodes_params.at(last_node).pose);
        }

        return true;
        MRPT_END;
}  // end of addNodeBatchFromNeighbor

template <class GRAPH_T>
bool CGraphSlamEngine_MR<GRAPH_T>::findTFsWithAllNeighbors()
{
        MRPT_START;
        using namespace mrpt::math;

        if (this->m_graph.nodeCount() < m_opts.inter_group_node_count_thresh)
        {
                return false;
        }

        // cache the gridmap so that it is computed only once during all the
        // findMatches*  calls
        this->computeMap();

        bool ret_val = false;  // at *any* node registration, change to true

        // iterate over all neighbors - run map-matching proc.
        for (typename neighbors_t::iterator neighbors_it = m_neighbors.begin();
                 neighbors_it != m_neighbors.end(); ++neighbors_it)
        {
                // run matching proc with neighbor only if I haven't found an initial
                // inter-graph TF
                if (!m_neighbor_to_found_initial_tf.at(*neighbors_it))
                {
                        bool loc_ret_val = findTFWithNeighbor(*neighbors_it);
                        if (loc_ret_val)
                        {
                                MRPT_LOG_DEBUG_STREAM(
                                        "Updating own cached map after successful node "
                                        "registration...");
                                // update own map if new nodes have been added.
                                this->computeMap();

                                // mark current neighbor tf as found.
                                m_neighbor_to_found_initial_tf.at(*neighbors_it) = true;

                                ret_val = true;
                        }
                }
        }

        return ret_val;
        MRPT_END;
}  // end of findTFsWithAllNeighbors

template <class GRAPH_T>
bool CGraphSlamEngine_MR<GRAPH_T>::findTFWithNeighbor(
        TNeighborAgentProps* neighbor)
{
        MRPT_START;
        using namespace mrpt::slam;
        using namespace mrpt::math;
        using namespace mrpt::poses;
        using namespace mrpt::maps;
        using namespace mrpt::graphslam::detail;

        bool ret_val = false;

        std::vector<TNodeID> neighbor_nodes;
        std::map<TNodeID, node_props_t> nodes_params;
        neighbor->getCachedNodes(
                &neighbor_nodes, &nodes_params,
                /*only unused=*/false);
        if (neighbor_nodes.size() < m_opts.inter_group_node_count_thresh ||
                !neighbor->hasNewData())
        {
                return false;
        }

        //
        // run alignment procedure
        //
        COccupancyGridMap2D::Ptr neighbor_gridmap = neighbor->getGridMap();
        CGridMapAligner gridmap_aligner;
        gridmap_aligner.options = m_alignment_options;

        CGridMapAligner::TReturnInfo results;

        // TODO - make use of agents' rendez-vous in the initial estimation
        CPosePDFGaussian init_estim;
        init_estim.mean = neighbor->tf_self_to_neighbor_first_integrated_pose;
        this->logFmt(
                LVL_INFO, "Trying to align the maps, initial estimation: %s",
                init_estim.mean.asString().c_str());

        // Save them for debugging reasons
        // neighbor_gridmap->saveMetricMapRepresentationToFile(this->getLoggerName()
        // +
        // "_other");
        // this->m_gridmap_cached->saveMetricMapRepresentationToFile(this->getLoggerName()
        // + "_self");

        TMetricMapAlignmentResult alignRes;

        const CPosePDF::Ptr pdf_tmp = gridmap_aligner.AlignPDF(
                this->m_gridmap_cached.get(), neighbor_gridmap.get(), init_estim,
                alignRes);

        const auto run_time = alignRes.executionTime;

        this->logFmt(LVL_INFO, "Elapsed Time: %f", run_time);
        CPosePDFSOG::Ptr pdf_out = CPosePDFSOG::Create();
        pdf_out->copyFrom(*pdf_tmp);

        CPose2D pose_out;
        CMatrixDouble33 cov_out;
        pdf_out->getMostLikelyCovarianceAndMean(cov_out, pose_out);

        this->logFmt(
                LVL_INFO, "%s\n",
                getGridMapAlignmentResultsAsString(*pdf_tmp, results).c_str());

        // dismiss this?
        if (results.goodness > 0.999 || isEssentiallyZero(pose_out))
        {
                return false;
        }

        //
        //
        // Map-merging operation is successful. Integrate graph into own.

        //
        // ask for condensed measurements graph
        //
        mrpt_msgs::GetCMGraph cm_graph_srv;
        typedef mrpt_msgs::GetCMGraphRequest::_node_ids_type node_id_type;
        node_id_type& matched_nodeIDs = cm_graph_srv.request.node_ids;

        // which nodes to ask the condensed graph for
        // I assume that no nodes of the other graph have been integrated yet.
        for (typename std::vector<TNodeID>::const_iterator n_cit =
                         neighbor_nodes.begin();
                 n_cit != neighbor_nodes.end(); ++n_cit)
        {
                matched_nodeIDs.push_back(*n_cit);      // all used nodes
        }

        MRPT_LOG_DEBUG_STREAM("Asking for the graph.");
        bool res = neighbor->cm_graph_srvclient.call(cm_graph_srv);      // blocking
        if (!res)
        {
                MRPT_LOG_ERROR_STREAM("Service call for CM_Graph failed.");
                return false;  // skip this if failed to fetch other's graph
        }
        MRPT_LOG_DEBUG_STREAM("Fetched graph successfully.");
        MRPT_LOG_DEBUG_STREAM(cm_graph_srv.response.cm_graph);

        GRAPH_T other_graph;
        mrpt_msgs_bridge::fromROS(cm_graph_srv.response.cm_graph, other_graph);

        //
        // merge graphs
        //
        MRPT_LOG_WARN_STREAM(
                "Merging graph of \"" << neighbor->getAgentNs() << "\"...");
        hypots_t graph_conns;
        // build the only hypothesis connecting graph with neighbor subgraph
        // own origin -> first valid nodeID of neighbor
        {
                hypot_t graph_conn;
                constraint_t c;
                c.mean = pose_out;
                // assign the inverse of the found covariance to c
                cov_out = c.cov_inv.inverse();
                graph_conn.setEdge(c);
                // TODO - change this.
                graph_conn.from = 0;  // self
                graph_conn.to = *neighbor_nodes.begin();  // other

                graph_conn.goodness = results.goodness;
                graph_conns.push_back(graph_conn);
        }

        std::map<TNodeID, TNodeID> old_to_new_mappings;
        this->m_graph.mergeGraph(
                other_graph, graph_conns,
                /*hypots_from_other_to_self=*/false, &old_to_new_mappings);

        //
        // Mark Nodes/LaserScans as integrated
        //
        MRPT_LOG_WARN_STREAM("Marking used nodes as integrated - Integrating LSs");
        nodes_to_scans2D_t new_nodeIDs_to_scans_pairs;
        for (typename std::vector<TNodeID>::const_iterator n_cit =
                         neighbor_nodes.begin();
                 n_cit != neighbor_nodes.end(); ++n_cit)
        {
                // Mark the neighbor's used nodes as integrated
                neighbor->nodeID_to_is_integrated.at(*n_cit) = true;

                // Integrate LaserScans at the newly integrated nodeIDs in own
                // nodes_to_laser_scans2D map
                new_nodeIDs_to_scans_pairs.insert(make_pair(
                        old_to_new_mappings.at(*n_cit), nodes_params.at(*n_cit).scan));
                MRPT_LOG_INFO_STREAM(
                        "Adding nodeID-LS of nodeID: "
                        << "\t[old:] " << *n_cit << endl
                        << "| [new:] " << old_to_new_mappings.at(*n_cit));
        }

        this->m_nodes_to_laser_scans2D.insert(
                new_nodeIDs_to_scans_pairs.begin(), new_nodeIDs_to_scans_pairs.end());
        edge_reg_mr_t* edge_reg_mr = dynamic_cast<edge_reg_mr_t*>(this->m_edge_reg);
        edge_reg_mr->addBatchOfNodeIDsAndScans(new_nodeIDs_to_scans_pairs);

        // Call for a Full graph visualization update and Dijkstra update -
        // CGraphSlamOptimizer
        // MRPT_LOG_WARN_STREAM("Optimizing graph..." << endl);
        // this->m_optimizer->optimizeGraph();
        MRPT_LOG_WARN_STREAM("Executing Dijkstra..." << endl);
        this->execDijkstraNodesEstimation();

        neighbor->resetFlags();

        // update the initial tf estimation
        neighbor->tf_self_to_neighbor_first_integrated_pose = pose_out;

        // keep track of the last integrated nodeID
        {
                TNodeID last_node = *neighbor_nodes.rbegin();
                neighbor->last_integrated_pair_neighbor_frame =
                        make_pair(last_node, nodes_params.at(last_node).pose);
        }

        MRPT_LOG_WARN_STREAM(
                "Nodes of neighbor [" << neighbor->getAgentNs()
                                                          << "] have been integrated successfully");

        ret_val = true;

        return ret_val;
        MRPT_END;
}  // end if findTFWithNeighbor

template <class GRAPH_T>
bool CGraphSlamEngine_MR<GRAPH_T>::_execGraphSlamStep(
        mrpt::obs::CActionCollection::Ptr& action,
        mrpt::obs::CSensoryFrame::Ptr& observations,
        mrpt::obs::CObservation::Ptr& observation, size_t& rawlog_entry)
{
        MRPT_START;
        using namespace mrpt::graphslam::deciders;
        using namespace mrpt;

        // call parent method
        bool continue_exec = parent_t::_execGraphSlamStep(
                action, observations, observation, rawlog_entry);

        // find matches between own nodes and those of the neighbors
        bool did_register_from_map_merge;
        if (!m_opts.conservative_find_initial_tfs_to_neighbors)
        {
                did_register_from_map_merge = this->findTFsWithAllNeighbors();
        }
        else
        {  // inter-graph TF is available - add new nodes
                THROW_EXCEPTION(
                        "Conservative inter-graph TF computation is not yet implemented.");
        }

        bool did_register_from_batches = this->addNodeBatchesFromAllNeighbors();
        m_registered_multiple_nodes =
                (did_register_from_map_merge || did_register_from_batches);

        if (m_registered_multiple_nodes)
        {
                if (this->m_enable_visuals)
                {
                        this->updateAllVisuals();
                }
        }

        return continue_exec;
        MRPT_END;
}  // end of _execGraphSlamStep

template <class GRAPH_T>
void CGraphSlamEngine_MR<GRAPH_T>::initClass()
{
        using namespace mrpt::graphslam;
        using namespace std;

        // initialization of topic namespace names
        // TODO - put these into seperate method
        m_mr_ns = "mr_info";

        // initialization of topic names / services
        m_list_neighbors_topic = m_mr_ns + "/" + "neighbors";
        m_last_regd_id_scan_topic = m_mr_ns + "/" + "last_nodeID_laser_scan";
        m_last_regd_nodes_topic = m_mr_ns + "/" + "last_regd_nodes";
        m_cm_graph_service = m_mr_ns + "/" + "get_cm_graph";

        this->m_class_name = "CGraphSlamEngine_MR_" + m_conn_manager.getTrimmedNs();
        this->setLoggerName(this->m_class_name);
        this->setupComm();

        // Make sure that master_discovery and master_sync are up before trying to
        // connect to other agents
        std::vector<string> nodes_up;
        ros::master::getNodes(nodes_up);
        // If both master_dicovery and master_sync are running, then the
        // /master_sync/get_sync_info service should be available
        MRPT_LOG_INFO_STREAM(
                "Waiting for master_discovery, master_sync nodes to come up....");
        ros::service::waitForService(
                "/master_sync/get_sync_info");  // block until it is
        MRPT_LOG_INFO_STREAM("master_discovery, master_sync are available.");

        this->m_node_reg->setClassName(
                this->m_node_reg->getClassName() + "_" + m_conn_manager.getTrimmedNs());
        this->m_edge_reg->setClassName(
                this->m_edge_reg->getClassName() + "_" + m_conn_manager.getTrimmedNs());
        this->m_optimizer->setClassName(
                this->m_optimizer->getClassName() + "_" +
                m_conn_manager.getTrimmedNs());

        // in case of Multi-robot specific deciders/optimizers (they
        // inherit from the CDeciderOrOptimizer_ROS interface) set the
        // CConnectionManager*
        // NOTE: It's not certain, even though we are running multi-robot graphSLAM
        // that all these classes do inherit from the
        // CRegistrationDeciderOrOptimizer_MR base class. They might be more generic
        // and not care about the multi-robot nature of the algorithm (e.g.
        // optimization scheme)
        {  // NRD
                CRegistrationDeciderOrOptimizer_MR<GRAPH_T>* dec_opt_mr =
                        dynamic_cast<CRegistrationDeciderOrOptimizer_MR<GRAPH_T>*>(
                                this->m_node_reg);

                if (dec_opt_mr)
                {
                        dec_opt_mr->setCConnectionManagerPtr(&m_conn_manager);
                }
        }
        {  // ERD
                CRegistrationDeciderOrOptimizer_MR<GRAPH_T>* dec_opt_mr =
                        dynamic_cast<CRegistrationDeciderOrOptimizer_MR<GRAPH_T>*>(
                                this->m_edge_reg);
                ASSERT_(dec_opt_mr);
                dec_opt_mr->setCConnectionManagerPtr(&m_conn_manager);
                dec_opt_mr->setCGraphSlamEnginePtr(this);
        }
        {  // GSO
                CRegistrationDeciderOrOptimizer_MR<GRAPH_T>* dec_opt_mr =
                        dynamic_cast<CRegistrationDeciderOrOptimizer_MR<GRAPH_T>*>(
                                this->m_optimizer);
                if (dec_opt_mr)
                {
                        dec_opt_mr->setCConnectionManagerPtr(&m_conn_manager);
                }
        }
        // display messages with the names of the deciders, optimizer and agent
        // string ID
        if (this->m_enable_visuals)
        {
                // NRD
                this->m_win_manager->assignTextMessageParameters(
                        /* offset_y* = */ &m_offset_y_nrd,
                        /* text_index* = */ &m_text_index_nrd);
                this->m_win_manager->addTextMessage(
                        this->m_offset_x_left, -m_offset_y_nrd,
                        mrpt::format("NRD: %s", this->m_node_reg->getClassName().c_str()),
                        TColorf(0, 0, 0),
                        /* unique_index = */ m_text_index_nrd);

                // ERD
                this->m_win_manager->assignTextMessageParameters(
                        /* offset_y* = */ &m_offset_y_erd,
                        /* text_index* = */ &m_text_index_erd);
                this->m_win_manager->addTextMessage(
                        this->m_offset_x_left, -m_offset_y_erd,
                        mrpt::format("ERD: %s", this->m_edge_reg->getClassName().c_str()),
                        TColorf(0, 0, 0),
                        /* unique_index = */ m_text_index_erd);

                // GSO
                this->m_win_manager->assignTextMessageParameters(
                        /* offset_y* = */ &m_offset_y_gso,
                        /* text_index* = */ &m_text_index_gso);
                this->m_win_manager->addTextMessage(
                        this->m_offset_x_left, -m_offset_y_gso,
                        mrpt::format("GSO: %s", this->m_optimizer->getClassName().c_str()),
                        TColorf(0, 0, 0),
                        /* unique_index = */ m_text_index_gso);

                // Agent Namespace
                this->m_win_manager->assignTextMessageParameters(
                        /* offset_y* = */ &m_offset_y_namespace,
                        /* text_index* = */ &m_text_index_namespace);
                this->m_win_manager->addTextMessage(
                        this->m_offset_x_left, -m_offset_y_namespace,
                        mrpt::format("Agent ID: %s", m_conn_manager.getTrimmedNs().c_str()),
                        TColorf(0, 0, 0),
                        /* unique_index = */ m_text_index_namespace);
        }
        this->readParams();

        this->m_optimized_map_color = m_neighbor_colors_manager.getNextTColor();

        // start the spinner for asynchronously servicing cm_graph requests
        cm_graph_async_spinner.start();
}  // end of initClass

template <class GRAPH_T>
mrpt::poses::CPose3D
        CGraphSlamEngine_MR<GRAPH_T>::getLSPoseForGridMapVisualization(
                const TNodeID nodeID) const
{
        MRPT_START;
        using namespace mrpt::graphs::detail;

        // if this is my own node ID return the corresponding CPose2D, otherwise
        // return the pose connecting own graph with the neighbor's graph

        const TMRSlamNodeAnnotations* node_annots =
                dynamic_cast<const TMRSlamNodeAnnotations*>(
                        &this->m_graph.nodes.at(nodeID));

        // Is the current nodeID registered by a neighboring agent or is it my own?
        TNeighborAgentProps* neighbor = NULL;
        this->getNeighborByAgentID(node_annots->agent_ID_str, neighbor);

        CPose3D laser_pose;
        if (!neighbor)
        {  // own node
                laser_pose = parent_t::getLSPoseForGridMapVisualization(nodeID);
        }
        else
        {  // not by me - return TF to neighbor graph
                laser_pose =
                        CPose3D(neighbor->tf_self_to_neighbor_first_integrated_pose);
        }
        return laser_pose;

        MRPT_END;
}

template <class GRAPH_T>
bool CGraphSlamEngine_MR<GRAPH_T>::getNeighborByAgentID(
        const std::string& agent_ID_str, TNeighborAgentProps*& neighbor) const
{
        MRPT_START;

        bool ret = false;
        for (auto neighbors_it = m_neighbors.begin();
                 neighbors_it != m_neighbors.end(); ++neighbors_it)
        {
                if ((*neighbors_it)->getAgentNs() == agent_ID_str)
                {
                        ret = true;
                        neighbor = *neighbors_it;
                        break;
                }
        }

        return ret;
        MRPT_END;
}

template <class GRAPH_T>
void CGraphSlamEngine_MR<GRAPH_T>::usePublishersBroadcasters()
{
        MRPT_START;
        using namespace mrpt_msgs;
        using namespace std;
        using namespace mrpt::math;
        using ::operator==;

        // call the parent class
        parent_t::usePublishersBroadcasters();

        // update list of neighbors that the current agent can communicate with.
        mrpt_msgs::GraphSlamAgents nearby_slam_agents;
        m_conn_manager.getNearbySlamAgents(
                &nearby_slam_agents,
                /*ignore_self = */ true);
        m_list_neighbors_pub.publish(nearby_slam_agents);

        // Initialize TNeighborAgentProps
        // for each *new* GraphSlamAgent we should add a TNeighborAgentProps
        // instance, and initialize its subscribers so that we fetch every new
        // LaserScan and list of modified nodes it publishes
        {
                for (GraphSlamAgents::_list_type::const_iterator it =
                                 nearby_slam_agents.list.begin();
                         it != nearby_slam_agents.list.end(); ++it)
                {
                        const GraphSlamAgent& gsa = *it;

                        // Is the current GraphSlamAgent already registered?
                        const auto search = [gsa](const TNeighborAgentProps* neighbor) {
                                return (neighbor->agent == gsa);
                        };
                        typename neighbors_t::const_iterator neighbor_it =
                                find_if(m_neighbors.begin(), m_neighbors.end(), search);

                        if (neighbor_it == m_neighbors.end())
                        {  // current gsa not found, add it

                                MRPT_LOG_DEBUG_STREAM(
                                        "Initializing NeighborAgentProps instance for "
                                        << gsa.name.data);
                                m_neighbors.push_back(new TNeighborAgentProps(*this, gsa));
                                TNeighborAgentProps* latest_neighbor = m_neighbors.back();
                                latest_neighbor->setTColor(
                                        m_neighbor_colors_manager.getNextTColor());
                                m_neighbor_to_found_initial_tf.insert(
                                        make_pair(latest_neighbor, false));
                                latest_neighbor->setupComm();
                        }
                }
        }

        this->pubUpdatedNodesList();
        this->pubLastRegdIDScan();

        MRPT_END;
}  // end of usePublishersBroadcasters

template <class GRAPH_T>
bool CGraphSlamEngine_MR<GRAPH_T>::pubUpdatedNodesList()
{
        MRPT_START;
        using namespace mrpt_msgs;

        // update the last X NodeIDs + positions; Do it only when a new node is
        // inserted. notified of this change anyway after a new node addition
        if (this->m_graph_nodes_last_size == this->m_graph.nodes.size())
        {
                return false;
        }
        MRPT_LOG_DEBUG_STREAM("Updating list of node poses");

        // send at most m_num_last_rgd_nodes
        typename GRAPH_T::global_poses_t poses_to_send;
        int poses_counter = 0;
        // fill the NodeIDWithPoseVec msg
        NodeIDWithPoseVec ros_nodes;

        // send up to num_last_regd_nodes Nodes - start from end.
        for (typename GRAPH_T::global_poses_t::const_reverse_iterator cit =
                         this->m_graph.nodes.rbegin();
                 (poses_counter <= m_opts.num_last_regd_nodes &&
                  cit != this->m_graph.nodes.rend());
                 ++cit)
        {
                // Do not resend nodes of others, registered in own graph.
                if (cit->second.agent_ID_str != m_conn_manager.getTrimmedNs())
                {
                        continue;  // skip this.
                }

                NodeIDWithPose curr_node_w_pose;
                // send basics - NodeID, Pose
                curr_node_w_pose.node_id = cit->first;
                curr_node_w_pose.pose = mrpt::ros1bridge::toROS_Pose(cit->second);

                // send mr-fields
                curr_node_w_pose.str_id.data = cit->second.agent_ID_str;
                curr_node_w_pose.node_id_loc = cit->second.nodeID_loc;

                ros_nodes.vec.push_back(curr_node_w_pose);

                poses_counter++;
        }

        m_last_regd_nodes_pub.publish(ros_nodes);

        // update the last known size
        m_graph_nodes_last_size = this->m_graph.nodeCount();

        bool res = false;
        if (poses_counter)
        {
                res = true;
        }

        return res;
        MRPT_END;
}  // end of pubUpdatedNodesList

template <class GRAPH_T>
bool CGraphSlamEngine_MR<GRAPH_T>::pubLastRegdIDScan()
{
        MRPT_START;
        using namespace mrpt_msgs;

        // Update the last registered scan + associated nodeID
        // Last registered scan always corresponds to the *last* element of the of
        // the published NodeIDWithPoseVec that is published above.
        //
        // - Check if map is empty
        // - Have I already published the last laser scan?
        if (!this->m_nodes_to_laser_scans2D.empty() &&
                m_nodes_to_laser_scans2D_last_size <
                        this->m_nodes_to_laser_scans2D.size())
        {
                // last registered scan
                MRPT_NodeIDWithLaserScan mrpt_last_regd_id_scan =
                        *(this->m_nodes_to_laser_scans2D.rbegin());

                // if this is a mr-registered nodeID+LS, skip it.
                if (!this->isOwnNodeID(mrpt_last_regd_id_scan.first))
                {
                        return false;
                }

                // MRPT_LOG_DEBUG_STREAM
                //<< "Publishing LaserScan of nodeID \""
                //<< mrpt_last_regd_id_scan.first << "\"";
                ASSERT_(mrpt_last_regd_id_scan.second);

                // convert to ROS msg
                mrpt_msgs::NodeIDWithLaserScan ros_last_regd_id_scan;
                mrpt::ros1bridge::toROS(
                        *(mrpt_last_regd_id_scan.second), ros_last_regd_id_scan.scan);
                ros_last_regd_id_scan.node_id = mrpt_last_regd_id_scan.first;

                m_last_regd_id_scan_pub.publish(ros_last_regd_id_scan);

                // update the last known size.
                m_nodes_to_laser_scans2D_last_size =
                        this->m_nodes_to_laser_scans2D.size();

                return true;
        }
        else
        {
                return false;
        }

        MRPT_END;
}  // end of pubLastRegdIDScan

template <class GRAPH_T>
bool CGraphSlamEngine_MR<GRAPH_T>::isOwnNodeID(
        const TNodeID nodeID, const global_pose_t* pose_out /*=NULL*/) const
{
        MRPT_START;
        using namespace mrpt::graphs::detail;

        // make sure give node is in the graph
        typename GRAPH_T::global_poses_t::const_iterator global_pose_search =
                this->m_graph.nodes.find(nodeID);
        ASSERTMSG_(
                global_pose_search != this->m_graph.nodes.end(),
                mrpt::format(
                        "isOwnNodeID called for nodeID \"%lu\" which is not "
                        "found in the graph",
                        static_cast<unsigned long>(nodeID)));

        // fill pointer to global_pose_t
        if (pose_out)
        {
                pose_out = &global_pose_search->second;
        }

        bool res = false;
        const TMRSlamNodeAnnotations* node_annots =
                dynamic_cast<const TMRSlamNodeAnnotations*>(
                        &global_pose_search->second);
        if ((node_annots &&
                 node_annots->agent_ID_str == m_conn_manager.getTrimmedNs()) ||
                (!node_annots))
        {
                res = true;
        }

        return res;

        MRPT_END;
}  // end of isOwnNodeID

template <class GRAPH_T>
void CGraphSlamEngine_MR<GRAPH_T>::readParams()
{
        using namespace mrpt::slam;

        this->readROSParameters();

        // GridMap Alignment
        m_alignment_options.loadFromConfigFileName(
                this->m_config_fname, m_sec_alignment_params);

        // Thu Jun 8 17:02:17 EEST 2017, Nikos Koukis
        // other option ends up in segfault.
        m_alignment_options.methodSelection = CGridMapAligner::amModifiedRANSAC;

        m_opts.loadFromConfigFileName(this->m_config_fname, m_sec_mr_slam_params);
}  // end of readParams

template <class GRAPH_T>
void CGraphSlamEngine_MR<GRAPH_T>::readROSParameters()
{
        // call parent method first in case the parent wants to ask for any ROS
        // parameters
        parent_t::readROSParameters();
}

template <class GRAPH_T>
void CGraphSlamEngine_MR<GRAPH_T>::printParams() const
{
        parent_t::printParams();
        m_alignment_options.dumpToConsole();
        m_opts.dumpToConsole();
}

template <class GRAPH_T>
void CGraphSlamEngine_MR<GRAPH_T>::setupSubs()
{
}

template <class GRAPH_T>
void CGraphSlamEngine_MR<GRAPH_T>::setupPubs()
{
        using namespace mrpt_msgs;
        using namespace sensor_msgs;

        m_list_neighbors_pub = m_nh->advertise<GraphSlamAgents>(
                m_list_neighbors_topic, this->m_queue_size,
                /*latch = */ true);

        // last registered laser scan - by default this corresponds to the last
        // nodeID of the vector of last registered nodes.
        m_last_regd_id_scan_pub = m_nh->advertise<NodeIDWithLaserScan>(
                m_last_regd_id_scan_topic, this->m_queue_size,
                /*latch = */ true);

        // last X nodeIDs + positions
        m_last_regd_nodes_pub = m_nh->advertise<NodeIDWithPoseVec>(
                m_last_regd_nodes_topic, this->m_queue_size,
                /*latch = */ true);
}

template <class GRAPH_T>
void CGraphSlamEngine_MR<GRAPH_T>::setupSrvs()
{
        // cm_graph service requests are handled by the custom custom_service_queue
        // CallbackQueue
        ros::CallbackQueueInterface* global_queue = m_nh->getCallbackQueue();
        m_nh->setCallbackQueue(&this->custom_service_queue);

        m_cm_graph_srvserver = m_nh->advertiseService(
                m_cm_graph_service, &CGraphSlamEngine_MR<GRAPH_T>::getCMGraph, this);

        m_nh->setCallbackQueue(global_queue);
}

template <class GRAPH_T>
bool CGraphSlamEngine_MR<GRAPH_T>::getCMGraph(
        mrpt_msgs::GetCMGraph::Request& req, mrpt_msgs::GetCMGraph::Response& res)
{
        using namespace std;
        using namespace mrpt::math;

        set<TNodeID> nodes_set(req.node_ids.begin(), req.node_ids.end());
        MRPT_LOG_INFO_STREAM(
                "Called the GetCMGraph service for nodeIDs: "
                << getSTLContainerAsString(nodes_set));

        if (nodes_set.size() < 2)
        {
                return false;
        }

        // fill the given Response with the ROS NetworkOfPoses
        GRAPH_T mrpt_subgraph;
        this->m_graph.extractSubGraph(
                nodes_set, &mrpt_subgraph,
                /*root_node = */ INVALID_NODEID,
                /*auto_expand_set=*/false);
        mrpt_msgs_bridge::toROS(mrpt_subgraph, res.cm_graph);
        return true;
}  // end of getCMGraph

template <class GRAPH_T>
void CGraphSlamEngine_MR<GRAPH_T>::setObjectPropsFromNodeID(
        const TNodeID nodeID, mrpt::opengl::CSetOfObjects::Ptr& viz_object)
{
        MRPT_START;

        // who registered this node?
        TNeighborAgentProps* neighbor = NULL;
        std::string& agent_ID_str = this->m_graph.nodes.at(nodeID).agent_ID_str;
        bool is_not_own = getNeighborByAgentID(agent_ID_str, neighbor);

        TColor obj_color;
        if (!is_not_own)
        {  // I registered this.
                // use the standard maps color
                obj_color = this->m_optimized_map_color;
        }
        else
        {
                ASSERT_(neighbor);
                obj_color = neighbor->color;
        }
        viz_object->setColor_u8(obj_color);

        MRPT_END;
}  // end of setObjectPropsFromNodeID

template <class GRAPH_T>
void CGraphSlamEngine_MR<GRAPH_T>::monitorNodeRegistration(
        bool registered /*=false*/, std::string class_name /*="Class"*/)
{
        MRPT_START;

        if (m_registered_multiple_nodes)
        {
                MRPT_LOG_ERROR_STREAM("m_registered_multiple_nodes = TRUE!");
                m_registered_multiple_nodes = !m_registered_multiple_nodes;
                this->m_nodeID_max = this->m_graph.nodeCount() - 1;
        }
        else
        {
                parent_t::monitorNodeRegistration(registered, class_name);
        }

        MRPT_END;
}  // end of monitorNodeRegistration

template <class GRAPH_T>
void CGraphSlamEngine_MR<GRAPH_T>::getRobotEstimatedTrajectory(
        typename GRAPH_T::global_poses_t* graph_poses) const
{
        MRPT_START;
        ASSERT_(graph_poses);

        for (const auto& n : this->m_graph.nodes)
        {
                if (n.second.agent_ID_str == m_conn_manager.getTrimmedNs())
                {
                        graph_poses->insert(n);
                }
        }

        MRPT_END;
}  // end of getRobotEstimatedTrajectory

template <class GRAPH_T>
void CGraphSlamEngine_MR<GRAPH_T>::getAllOwnNodes(
        std::set<TNodeID>* nodes_set) const
{
        ASSERT_(nodes_set);
        nodes_set->clear();

        for (const auto& n : this->m_graph.nodes)
        {
                if (n.second.agent_ID_str == m_conn_manager.getTrimmedNs())
                {
                        nodes_set->insert(n.first);
                }
        }
}  // end of getAllOwnNodes

template <class GRAPH_T>
void CGraphSlamEngine_MR<GRAPH_T>::getNodeIDsOfEstimatedTrajectory(
        std::set<TNodeID>* nodes_set) const
{
        ASSERT_(nodes_set);
        this->getAllOwnNodes(nodes_set);
}  // end of getNodeIDsOfEstimatedTrajectory


template <class GRAPH_T>
CGraphSlamEngine_MR<GRAPH_T>::TNeighborAgentProps::TNeighborAgentProps(
        CGraphSlamEngine_MR<GRAPH_T>& engine_in,
        const mrpt_msgs::GraphSlamAgent& agent_in)
        : engine(engine_in), agent(agent_in), has_setup_comm(false)
{
        nh = engine.m_nh;
        m_queue_size = engine.m_queue_size;
        this->resetFlags();

        // fill the full paths of the topics to subscribe
        // ASSUMPTION: agents namespaces start at the root "/"
        this->last_regd_nodes_topic =
                "/" + agent.topic_namespace.data + "/" + engine.m_last_regd_nodes_topic;
        this->last_regd_id_scan_topic = "/" + agent.topic_namespace.data + "/" +
                                                                        engine.m_last_regd_id_scan_topic;
        this->cm_graph_service =
                "/" + agent.topic_namespace.data + "/" + engine.m_cm_graph_service;

        engine.logFmt(
                LVL_DEBUG,
                "In constructor of TNeighborAgentProps for topic namespace: %s",
                agent.topic_namespace.data.c_str());

        // initialize the occupancy map based on the engine's gridmap properties
        gridmap_cached = mrpt::maps::COccupancyGridMap2D::Create();
        mrpt::maps::COccupancyGridMap2D::Ptr eng_gridmap = engine.m_gridmap_cached;
        gridmap_cached->setSize(
                eng_gridmap->getXMin(), eng_gridmap->getXMax(), eng_gridmap->getYMin(),
                eng_gridmap->getYMax(), eng_gridmap->getResolution());

}  // TNeighborAgentProps::TNeighborAgentProps

template <class GRAPH_T>
CGraphSlamEngine_MR<GRAPH_T>::TNeighborAgentProps::~TNeighborAgentProps()
{
}

template <class GRAPH_T>
void CGraphSlamEngine_MR<GRAPH_T>::TNeighborAgentProps::setupComm()
{
        this->setupSubs();
        this->setupSrvs();

        engine.logFmt(
                LVL_DEBUG,
                "TNeighborAgentProps: Successfully set up subscribers/services "
                "to agent topics for namespace [%s].",
                agent.topic_namespace.data.c_str());

        has_setup_comm = true;
}

template <class GRAPH_T>
void CGraphSlamEngine_MR<GRAPH_T>::TNeighborAgentProps::setupSrvs()
{
        cm_graph_srvclient =
                nh->serviceClient<mrpt_msgs::GetCMGraph>(cm_graph_service);
}

template <class GRAPH_T>
void CGraphSlamEngine_MR<GRAPH_T>::TNeighborAgentProps::setupSubs()
{
        using namespace mrpt_msgs;

        last_regd_nodes_sub = nh->subscribe<NodeIDWithPoseVec>(
                last_regd_nodes_topic, m_queue_size,
                &TNeighborAgentProps::fetchUpdatedNodesList, this);
        last_regd_id_scan_sub = nh->subscribe<NodeIDWithLaserScan>(
                last_regd_id_scan_topic, m_queue_size,
                &TNeighborAgentProps::fetchLastRegdIDScan, this);
}

template <class GRAPH_T>
void CGraphSlamEngine_MR<GRAPH_T>::TNeighborAgentProps::fetchUpdatedNodesList(
        const mrpt_msgs::NodeIDWithPoseVec::ConstPtr& nodes)
{
        MRPT_START;
        using namespace mrpt_msgs;
        using namespace std;

        typedef typename GRAPH_T::constraint_t::type_value pose_t;
        engine.logFmt(LVL_DEBUG, "In fetchUpdatedNodesList method.");

        for (NodeIDWithPoseVec::_vec_type::const_iterator n_it = nodes->vec.begin();
                 n_it != nodes->vec.end(); ++n_it)
        {
                // insert in the set if not already there.
                TNodeID nodeID = static_cast<TNodeID>(n_it->node_id);
                std::pair<set<TNodeID>::iterator, bool> res =
                        nodeIDs_set.insert(nodeID);
                // if I just inserted this node mark it as not used (in own graph)
                if (res.second)
                {  // insertion took place.
                        engine.logFmt(
                                LVL_INFO, "Just fetched a new nodeID: %lu",
                                static_cast<unsigned long>(nodeID));
                        nodeID_to_is_integrated.insert(make_pair(n_it->node_id, false));
                }

                // update the poses
                pose_t curr_pose;
                curr_pose = pose_t(mrpt::ros1bridge::fromROS(n_it->pose));

                // note: use "operator[]" instead of "insert" so that if the key already
                // exists, the corresponding value is changed rather than ignored.
                poses[static_cast<TNodeID>(n_it->node_id)] = pose_t(curr_pose);
        }
        has_new_nodes = true;

        // TODO When using 3 graphSLAM agents GDB Shows that it crashes on
        // engine.logFmt lines. Fix this.
        //
        // engine.logFmt(LVL_DEBUG, // THIS CRASHES - GDB WHERE
        //"NodeIDs for topic namespace: %s -> [%s]",
        // agent.topic_namespace.data.c_str(),
        // mrpt::math::getSTLContainerAsString(vector<TNodeID>(
        // nodeIDs_set.begin(), nodeIDs_set.end())).c_str());
        // print poses just for verification
        // engine.logFmt(LVL_DEBUG, "Poses for topic namespace: %s",
        // agent.topic_namespace.data.c_str());
        // for (typename GRAPH_T::global_poses_t::const_iterator
        // p_it = poses.begin();
        // p_it != poses.end();
        //++p_it) {
        // std::string p_str; p_it->second.asString(p_str);
        // engine.logFmt(LVL_DEBUG, "nodeID: %lu | pose: %s",
        // static_cast<unsigned long>(p_it->first),
        // p_str.c_str());
        //}
        // TODO - These also seem to crash sometimes
        // cout << "Agent information: " << agent << endl;
        // cout << "Nodes: " <<
        // mrpt::math::getSTLContainerAsString(vector<TNodeID>(nodeIDs_set.begin(),
        // nodeIDs_set.end()));
        // print nodeIDs just for verification

        MRPT_END;
}  // end of fetchUpdatedNodesList

template <class GRAPH_T>
void CGraphSlamEngine_MR<GRAPH_T>::TNeighborAgentProps::fetchLastRegdIDScan(
        const mrpt_msgs::NodeIDWithLaserScan::ConstPtr& last_regd_id_scan)
{
        MRPT_START;
        using namespace std;
        ASSERT_(last_regd_id_scan);
        engine.logFmt(LVL_DEBUG, "In fetchLastRegdIDScan method.");

        // Pose may not be available due to timing in publishing of the
        // corresponding topics. Just keep it in ROS form and then convert them to
        // MRPT form when needed.
        ros_scans.push_back(*last_regd_id_scan);
        has_new_scans = true;

        MRPT_END;
}  // end of fetchLastRegdIDScan

template <class GRAPH_T>
void CGraphSlamEngine_MR<GRAPH_T>::TNeighborAgentProps::getCachedNodes(
        std::vector<TNodeID>* nodeIDs /*=NULL*/,
        std::map<TNodeID, node_props_t>* nodes_params /*=NULL*/,
        bool only_unused /*=true*/) const
{
        MRPT_START;
        using namespace mrpt::obs;
        using namespace mrpt::math;
        using namespace std;
        using namespace mrpt::poses;

        // at least one of the two args should be given.
        ASSERT_(nodeIDs || nodes_params);

        // traverse all nodes
        for (std::set<TNodeID>::const_iterator n_it = nodeIDs_set.begin();
                 n_it != nodeIDs_set.end(); ++n_it)
        {
                // Should I return only the unused ones?
                // If so, if the current nodeID is integrated, skip it.
                if (only_unused && nodeID_to_is_integrated.at(*n_it))
                {
                        continue;
                }

                // add the node properties
                if (nodes_params)
                {
                        std::pair<TNodeID, node_props_t>
                                params;  // current pair to be inserted.
                        const pose_t* p = &poses.at(*n_it);

                        params.first = *n_it;
                        params.second.pose = *p;
                        CObservation2DRangeScan::Ptr mrpt_scan =
                                CObservation2DRangeScan::Create();
                        const sensor_msgs::LaserScan* ros_laser_scan =
                                this->getLaserScanByNodeID(*n_it);

                        // if LaserScan not found, skip nodeID altogether.
                        //
                        // Its natural to have more poses than LaserScans since on every
                        // node registration I send a modified list of X node positions and
                        // just one LaserScan
                        if (!ros_laser_scan)
                        {
                                continue;
                        }

                        mrpt::ros1bridge::fromROS(*ros_laser_scan, CPose3D(*p), *mrpt_scan);
                        params.second.scan = mrpt_scan;

                        // insert the pair
                        nodes_params->insert(params);

                        // debugging message
                        // std::stringstream ss;
                        // ss << "\ntID: " << nodes_params->rbegin()->first
                        //<< " ==> Props: " << nodes_params->rbegin()->second;
                        // engine.logFmt(LVL_DEBUG, "%s", ss.str().c_str());
                }

                // add the nodeID
                if (nodeIDs)
                {
                        // do not return nodeIDs that don't have valid laserScans
                        // this is also checked at the prior if
                        if (!nodes_params && !this->getLaserScanByNodeID(*n_it))
                        {
                                continue;
                        }

                        nodeIDs->push_back(*n_it);
                }
        }

        MRPT_END;
}  // end of TNeighborAgentProps::getCachedNodes

template <class GRAPH_T>
void CGraphSlamEngine_MR<GRAPH_T>::TNeighborAgentProps::resetFlags() const
{
        has_new_nodes = false;
        has_new_scans = false;
}

template <class GRAPH_T>
bool CGraphSlamEngine_MR<GRAPH_T>::TNeighborAgentProps::hasNewNodesBatch(
        int new_batch_size)
{
        MRPT_START;

        auto is_not_integrated = [this](const std::pair<TNodeID, bool> pair) {
                return (pair.second == false && getLaserScanByNodeID(pair.first));
        };
        int not_integrated_num = count_if(
                nodeID_to_is_integrated.begin(), nodeID_to_is_integrated.end(),
                is_not_integrated);

        return (not_integrated_num >= new_batch_size);

        MRPT_END;
}

template <class GRAPH_T>
const sensor_msgs::LaserScan*
        CGraphSlamEngine_MR<GRAPH_T>::TNeighborAgentProps::getLaserScanByNodeID(
                const TNodeID nodeID) const
{
        MRPT_START;

        // assert that the current nodeID exists in the nodeIDs_set
        ASSERT_(nodeIDs_set.find(nodeID) != nodeIDs_set.end());

        for (std::vector<mrpt_msgs::NodeIDWithLaserScan>::const_iterator it =
                         ros_scans.begin();
                 it != ros_scans.end(); ++it)
        {
                if (it->node_id == nodeID)
                {
                        return &it->scan;
                }
        }

        // if out here, LaserScan doesn't exist.
        return 0;
        MRPT_END;
}  // end of TNeighborAgentProps::getLaserScanByNodeID

template <class GRAPH_T>
void CGraphSlamEngine_MR<GRAPH_T>::TNeighborAgentProps::fillOptPaths(
        const std::set<TNodeID>& nodeIDs, paths_t* opt_paths) const
{
        MRPT_START;
        using namespace std;
        typedef std::set<TNodeID>::const_iterator set_cit;

        // make sure that all given nodes belong in the nodeIDs_set.
        ASSERTMSG_(
                includes(
                        nodeIDs_set.begin(), nodeIDs_set.end(), nodeIDs.begin(),
                        nodeIDs.end()),
                "nodeIDs is not a strict subset of the current neighbor's nodes");
        ASSERT_(opt_paths);

        for (set_cit cit = nodeIDs.begin(); cit != std::prev(nodeIDs.end()); ++cit)
        {
                for (set_cit cit2 = std::next(cit); cit2 != nodeIDs.end(); ++cit2)
                {
                        constraint_t c = constraint_t(poses.at(*cit2) - poses.at(*cit));
                        c.cov_inv = mrpt::math::CMatrixFixedNumeric<
                                double, constraint_t::state_length,
                                constraint_t::state_length>();
                        c.cov_inv.unit();
                        c.cov_inv *= 500;

                        opt_paths->push_back(path_t(
                                /*start=*/*cit,
                                /*end=*/*cit2,
                                /*constraint=*/c));

                        engine.logFmt(
                                LVL_DEBUG, "Filling optimal path for nodes: %lu => %lu: %s",
                                static_cast<unsigned long>(*cit),
                                static_cast<unsigned long>(*cit2),
                                opt_paths->back()
                                        .curr_pose_pdf.getMeanVal()
                                        .asString()
                                        .c_str());
                }
        }
        MRPT_END;
}  // end of TNeighborAgentProps::fillOptPaths

template <class GRAPH_T>
void CGraphSlamEngine_MR<GRAPH_T>::TNeighborAgentProps::computeGridMap() const
{
        MRPT_START;
        using namespace mrpt::poses;
        using namespace mrpt;
        using namespace mrpt::math;
        using namespace std;

        gridmap_cached->clear();

        std::vector<TNodeID> nodeIDs;
        std::map<TNodeID, node_props_t> nodes_params;
        // get list of nodes, laser scans
        this->getCachedNodes(&nodeIDs, &nodes_params, false);

        // iterate over poses, scans. Add them to the gridmap.
        for (typename map<TNodeID, node_props_t>::const_iterator it =
                         nodes_params.begin();
                 it != nodes_params.end(); ++it)
        {
                const CPose3D curr_pose_3d;      // do not add the actual pose!
                auto obs = it->second.scan.get();
                gridmap_cached->insertObservation(*obs, curr_pose_3d);
        }

        MRPT_END;
}  // end of TNeighborAgentProps::computeGridMap

template <class GRAPH_T>
const mrpt::maps::COccupancyGridMap2D::Ptr&
        CGraphSlamEngine_MR<GRAPH_T>::TNeighborAgentProps::getGridMap() const
{
        MRPT_START;
        if (hasNewData())
        {
                this->computeGridMap();
        }

        return gridmap_cached;
        MRPT_END;
}  // end of TNeighborAgentProps::getGridMap

template <class GRAPH_T>
void CGraphSlamEngine_MR<GRAPH_T>::TNeighborAgentProps::getGridMap(
        mrpt::maps::COccupancyGridMap2D::Ptr& map) const
{
        MRPT_START;
        ASSERT_(map);

        if (hasNewData())
        {
                this->computeGridMap();
        }

        map->copyMapContentFrom(*gridmap_cached);
        MRPT_END;
}  // end of TNeighborAgentProps::getGridMap

template <class GRAPH_T>
bool CGraphSlamEngine_MR<GRAPH_T>::TNeighborAgentProps::hasNewData() const
{
        return has_new_nodes && has_new_scans;
}  // end of hasNewData

template <class GRAPH_T>
CGraphSlamEngine_MR<GRAPH_T>::TOptions::TOptions(const engine_mr_t& engine_in)
        : conservative_find_initial_tfs_to_neighbors(false),
          nodes_integration_batch_size(4),
          num_last_regd_nodes(10),
          inter_group_node_count_thresh(40),
          inter_group_node_count_thresh_minadv(25),
          engine(engine_in)
{
}  // end of TOptions::TOptions

template <class GRAPH_T>
CGraphSlamEngine_MR<GRAPH_T>::TOptions::~TOptions()
{
}  // end of TOptions::~TOptions

template <class GRAPH_T>
void CGraphSlamEngine_MR<GRAPH_T>::TOptions::loadFromConfigFile(
        const CConfigFileBase& source, const std::string& section)
{
        MRPT_LOAD_CONFIG_VAR(nodes_integration_batch_size, int, source, section);
        MRPT_LOAD_CONFIG_VAR(num_last_regd_nodes, int, source, section);

        MRPT_LOAD_CONFIG_VAR(
                conservative_find_initial_tfs_to_neighbors, bool, source, section);
        ASSERTMSG_(
                !conservative_find_initial_tfs_to_neighbors,
                "Conservative behavior is not yet implemented.");

        MRPT_LOAD_CONFIG_VAR(inter_group_node_count_thresh, int, source, section);
        // warn user if they choose smaller threshold.
        if (inter_group_node_count_thresh < inter_group_node_count_thresh_minadv)
        {
                engine.logFmt(
                        LVL_ERROR,
                        "inter_group_node_count_thresh [%d]"
                        "is set lower than the advised minimum [%d]",
                        static_cast<int>(inter_group_node_count_thresh),
                        static_cast<int>(inter_group_node_count_thresh_minadv));

                std::this_thread::sleep_for(std::chrono::milliseconds(2000));
        }

}  // end of TOptions::loadFromConfigFile

template <class GRAPH_T>
void CGraphSlamEngine_MR<GRAPH_T>::TOptions::dumpToTextStream(
        std::ostream& out) const
{
        LOADABLEOPTS_DUMP_VAR(nodes_integration_batch_size, int);
        LOADABLEOPTS_DUMP_VAR(num_last_regd_nodes, int);
        LOADABLEOPTS_DUMP_VAR(conservative_find_initial_tfs_to_neighbors, bool);
        LOADABLEOPTS_DUMP_VAR(static_cast<int>(inter_group_node_count_thresh), int)
        LOADABLEOPTS_DUMP_VAR(inter_group_node_count_thresh_minadv, int)

}  // end of TOptions::dumpToTextStream

}  // namespace graphslam
}  // namespace mrpt