EBV.hpp

/***********************************************************/
/***      ______  ____  ______                 _         ***/
/***     / ___\ \/ /\ \/ / ___|_ __ __ _ _ __ | |__      ***/
/***    | |    \  /  \  / |  _| '__/ _` | '_ \| '_ \     ***/
/***    | |___ /  \  /  \ |_| | | | (_| | |_) | | | |    ***/
/***     \____/_/\_\/_/\_\____|_|  \__,_| .__/|_| |_|    ***/
/***                                    |_|              ***/
/***********************************************************/
/***     Header-Only C++ Library for Graph               ***/
/***     Representation and Algorithms                   ***/
/***********************************************************/
/***     Author: ZigRazor                                ***/
/***     E-Mail: zigrazor@gmail.com                      ***/
/***********************************************************/
/***     Collaboration: -----------                      ***/
/***********************************************************/
/***     License: MPL v2.0                              ***/
/***********************************************************/
 
#ifndef __CXXGRAPH_PARTITIONING_EBV_H__
#define __CXXGRAPH_PARTITIONING_EBV_H__
 
#pragma once
 
#include "Partitioning/Utility/Globals.hpp"
#include "Edge/Edge.hpp"
#include "PartitionStrategy.hpp"
#include <unordered_map>
#include <chrono>
 
namespace CXXGRAPH
{
    namespace PARTITIONING
    {
        template <typename T>
        class EBV : public PartitionStrategy<T>
        {
        private:
            Globals GLOBALS;
 
        public:
            explicit EBV(Globals &G);
            ~EBV();
 
            void performStep(const Edge<T> &e, PartitionState<T> &Sstate);
        };
        template <typename T>
        EBV<T>::EBV(Globals &G) : GLOBALS(G)
        {
            //this->GLOBALS = G;
        }
        template <typename T>
        EBV<T>::~EBV()
        {
        }
        template <typename T>
        void EBV<T>::performStep(const Edge<T> &e, PartitionState<T> &state)
        {
            GLOBALS.edgeAnalyzed++;
 
            int P = GLOBALS.numberOfPartition;
            double alpha = GLOBALS.param1;
            double beta = GLOBALS.param2;
            unsigned long long edgeCardinality = GLOBALS.edgeCardinality;
            unsigned long long vertexCardinality = GLOBALS.vertexCardinality;
            auto nodePair = e.getNodePair();
            int u = nodePair.first->getId();
            int v = nodePair.second->getId();
 
            std::shared_ptr<Record<T>> u_record = state.getRecord(u);
            std::shared_ptr<Record<T>> v_record = state.getRecord(v);
 
            //*** ASK FOR LOCK
            bool locks_taken = false;
            while (!locks_taken)
            {
                srand((unsigned)time(NULL));
                int usleep_time = 2;
                while (!u_record->getLock())
                {
                    std::this_thread::sleep_for(std::chrono::microseconds(usleep_time));
                    usleep_time = (int)pow(usleep_time, 2);
                }
                usleep_time = 2;
                if (u != v)
                {
                    while (!v_record->getLock())
                    {
                        std::this_thread::sleep_for(std::chrono::microseconds(usleep_time));
                        usleep_time = (int)pow(usleep_time, 2);
 
                        if (usleep_time > GLOBALS.SLEEP_LIMIT)
                        {
                            u_record->releaseLock();
                            performStep(e, state);
                            return;
                        } //TO AVOID DEADLOCK
                    }
                }
                locks_taken = true;
            }
            //*** LOCK TAKEN
            int machine_id = -1;
 
            //*** COMPUTE SCORES, FIND MIN SCORE, AND COMPUTE CANDIDATES PARTITIONS
            std::map<int, double> eva;
            auto u_partition = u_record->getPartitions();
            auto v_partition = v_record->getPartitions();
            auto optimalEdgesNumber = (double)edgeCardinality / (double)P;
            auto optimalVerticesNumber = (double)vertexCardinality / (double)P;
            for (int i = 0; i < P; i++)
            {
                eva[i] = 0;
                if (u_partition.empty() || u_partition.find(i) == u_partition.end())
                {
                    eva[i] += 1;
                }
                if (v_partition.empty() || v_partition.find(i) == v_partition.end())
                {
                    eva[i] += 1;
                }
                eva[i] += alpha * (state.getMachineLoad(i) / optimalEdgesNumber) + beta * (state.getMachineLoadVertices(i) / optimalVerticesNumber);
            }
            //find min between eva
            double min = eva.at(0);
            machine_id = 0;
            for (auto &it : eva)
            {
                if (it.second < min)
                {
                    min = it.second;
                    machine_id = it.first;
                }
            }
            try
            {
                CoordinatedPartitionState<T> &cord_state = dynamic_cast<CoordinatedPartitionState<T> &>(state);
                //NEW UPDATE RECORDS RULE TO UPFDATE THE SIZE OF THE PARTITIONS EXPRESSED AS THE NUMBER OF VERTICES THEY CONTAINS
                if (!u_record->hasReplicaInPartition(machine_id))
                {
                    u_record->addPartition(machine_id);
                    cord_state.incrementMachineLoadVertices(machine_id);
                }
                if (!v_record->hasReplicaInPartition(machine_id))
                {
                    v_record->addPartition(machine_id);
                    cord_state.incrementMachineLoadVertices(machine_id);
                }
            }
            catch (const std::bad_cast &e)
            {
                // use employee's member functions
                //1-UPDATE RECORDS
                if (!u_record->hasReplicaInPartition(machine_id))
                {
                    u_record->addPartition(machine_id);
                }
                if (!v_record->hasReplicaInPartition(machine_id))
                {
                    v_record->addPartition(machine_id);
                }
            }
 
            //2-UPDATE EDGES
            state.incrementMachineLoad(machine_id, &e);
 
            //3-UPDATE DEGREES
            u_record->incrementDegree();
            v_record->incrementDegree();
 
            //*** RELEASE LOCK
            u_record->releaseLock();
            v_record->releaseLock();
            return;
        }
    }
}
 
#endif // __CXXGRAPH_PARTITIONING_EBV_H__