EdgeBalancedVertexCut.hpp

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/***      ______  ____  ______                 _         ***/
/***     / ___\ \/ /\ \/ / ___|_ __ __ _ _ __ | |__      ***/
/***    | |    \  /  \  / |  _| '__/ _` | '_ \| '_ \     ***/
/***    | |___ /  \  /  \ |_| | | | (_| | |_) | | | |    ***/
/***     \____/_/\_\/_/\_\____|_|  \__,_| .__/|_| |_|    ***/
/***                                    |_|              ***/
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/***     Header-Only C++ Library for Graph               ***/
/***     Representation and Algorithms                   ***/
/***********************************************************/
/***     Author: ZigRazor                                ***/
/***     E-Mail: zigrazor@gmail.com                      ***/
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/***     Collaboration: -----------                      ***/
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/***     License: MPL v2.0                              ***/
/***********************************************************/
 
#ifndef __CXXGRAPH_PARTITIONING_EDGEBALANCEDVERTEXCUT_H__
#define __CXXGRAPH_PARTITIONING_EDGEBALANCEDVERTEXCUT_H__
 
#pragma once
 
#include "Partitioning/Utility/Globals.hpp"
#include "Edge/Edge.hpp"
#include "PartitionStrategy.hpp"
#include <chrono>
 
namespace CXXGRAPH
{
    namespace PARTITIONING
    {
        template<typename T>
        class EdgeBalancedVertexCut : public PartitionStrategy<T>
        {
        private:
            Globals GLOBALS;
 
        public:
            explicit EdgeBalancedVertexCut(Globals &G);
            ~EdgeBalancedVertexCut();
 
            void performStep(const Edge<T> &e, PartitionState<T> &Sstate);
        };
        template <typename T>
        EdgeBalancedVertexCut<T>::EdgeBalancedVertexCut(Globals &G) : GLOBALS(G)
        {
            //this->GLOBALS = G;
        }
        template <typename T>
        EdgeBalancedVertexCut<T>::~EdgeBalancedVertexCut()
        {
        }
        template <typename T>
        void EdgeBalancedVertexCut<T>::performStep(const Edge<T> &e, PartitionState<T> &state)
        {
 
            int P = GLOBALS.numberOfPartition;            
            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
 
            //*** Check which partition has the less load
            int MIN_LOAD = state.getMachineLoad(0);
            int machine_id = 0;
            double MAX_SCORE = 0.0;
            
            for (int m = 0; m < P; m++)
            {
                int load = state.getMachineLoad(m);
                if ( load <= MIN_LOAD ){
                    MIN_LOAD = load;
                    machine_id = m;
                }
            }
            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_EDGEBALANCEDVERTEXCUT_H__