同步图计算框架GraphLite编程之图着色

   GraphLite github地址  https://github.com/schencoding/GraphLite

  图很适合进行分布式并行计算，比如最短路径，PageRank等问题，比较著名的图计算框架有Prege，cmu的GraphLab，apache的Giraph等。GraphLite属于BSP模型。

BSP模型如下图:

       也就是超步计算，apache giraph也属于此模式。

图着色在单机环境下的算法，最快一般是贪心算法，也就是每次去找不相邻的节点去着色，直到全部完成。我们在分布式并行计算环境下也要用贪心算法，每次找到不相邻的所有节点同时着色，在4个超步内完成一次着色，第一步根据出度的大小选择哪些节点可能要被着色，第二步处理冲突，第三步删除被选中节点和邻居节点之间的边，第四步给选中的节点染色。

#include <stdio.h>#include <string.h>#include <math.h>#include <list>#include "GraphLite.h"#define VERTEX_CLASS_NAME(name) GraphColorVertex##name#define NUM_VERTICES_COLORED             0#define NUM_VERTICES_UNKNOWN             1#define NUM_VERTICES_IN_SET              2#define NUM_VERTICES_NOT_IN_SET          3#define NUM_VERTICES_TENTATIVELY_IN_SET  4enum Phase {LOTTERY,CONFLICT_RESOLUTION,EDGE_CLEANING,COLOR_ASSIGNMENT};enum State {UNKNOWN,TENTATIVELY_IN_SET,NOT_IN_SET,IN_SET};enum MessageType {WANTS_TO_BE_IN_SET,IS_IN_SET};struct ColorVertex {long long id;int color;int isColored;enum State state;int isDeleted;int edgeNums;Phase phase;//list<long long> target;};struct Message {long long senderId;enum MessageType message;};long long V0;Phase phase;int colorId = 1;class VERTEX_CLASS_NAME(InputFormatter): public InputFormatter {public:    int64_t getVertexNum() {        unsigned long long n;        sscanf(m_ptotal_vertex_line, "%lld", &n);        m_total_vertex= n;        return m_total_vertex;    }    int64_t getEdgeNum() {        unsigned long long n;        sscanf(m_ptotal_edge_line, "%lld", &n);        m_total_edge= n;        return m_total_edge;    }    int getVertexValueSize() {        m_n_value_size = sizeof(ColorVertex);        return m_n_value_size;    }    int getEdgeValueSize() {        m_e_value_size = sizeof(int);        return m_e_value_size;    }    int getMessageValueSize() {        m_m_value_size = sizeof(struct Message);        return m_m_value_size;    }    void loadGraph() {        unsigned long long last_vertex;        unsigned long long from;        unsigned long long to;        int weight = 0; ColorVertex vertex;               int outdegree = 0;                const char *line= getEdgeLine();        // Note: modify this if an edge weight is to be read        //       modify the 'weight' variable        sscanf(line, "%lld %lld", &from, &to);        addEdge(from, to, &weight);vertex.color = -1;vertex.isDeleted = 0;        last_vertex = from;        ++outdegree;        for (int64_t i = 1; i < m_total_edge; ++i) {            line= getEdgeLine();            // Note: modify this if an edge weight is to be read            //       modify the 'weight' variable            sscanf(line, "%lld %lld", &from, &to);            if (last_vertex != from) {                addVertex(last_vertex, &vertex, outdegree);                last_vertex = from;                outdegree = 1;            } else {                ++outdegree;            }            addEdge(from, to, &weight);        }        addVertex(last_vertex, &vertex, outdegree);    }};class VERTEX_CLASS_NAME(OutputFormatter): public OutputFormatter {public:    void writeResult() {        int64_t vid;ColorVertex value;        char s[1024];        for (ResultIterator r_iter; ! r_iter.done(); r_iter.next() ) {            r_iter.getIdValue(vid, &value);            int n = sprintf(s, "%lld: %d\n", (unsigned long long)vid, value.color);            writeNextResLine(s, n);        }    }};// An aggregator that records a double value tom compute sumclass VERTEX_CLASS_NAME(Aggregator): public Aggregator<long long> {public:    void init() {        m_global = 0;        m_local = 0;    }    void* getGlobal() {        return &m_global;    }    void setGlobal(const void* p) {        m_global = * (long long *)p;    }    void* getLocal() {        return &m_local;    }    void merge(const void* p) {        m_global += * (long long *)p;    }    void accumulate(const void* p) {        m_local += * (long long *)p;    }};class VERTEX_CLASS_NAME(): public Vertex <ColorVertex, int, Message> {public:    void compute(MessageIterator* pmsgs) {  long long acc = 1;  ColorVertex tmp = getValue();  Message msg;  long long myId = getVertexId();          long long minId = myId;  int numNeighborsMovedIntoSet = 0;  double random;  double probability;  //list<long long>::iterator it;  //OutEdgeIterator iter = getOutEdgeIterator();  //printf("fcefef\n");   if(getSuperstep() == 0) {tmp.id = getVertexId();tmp.phase = LOTTERY;if(tmp.id == V0) {     tmp.color = 0;     tmp.isColored = 1;     tmp.state = IN_SET;     tmp.edgeNums = getOutEdgeIterator().size(); } else {     tmp.color = -1;             tmp.isColored = 0;     tmp.state = UNKNOWN;     tmp.edgeNums = getOutEdgeIterator().size(); }    } else {          if (getValue().isColored) {                       voteToHalt();                       return;                   }   State state = getValue().state;           switch (tmp.phase) {case LOTTERY:   printf("lottery\n");  switch (state) {    case UNKNOWN:       srand((unsigned)time(NULL));       random = (double)rand()/RAND_MAX/10000;       if (tmp.edgeNums == 0) {                                   tmp.state = IN_SET;                               } else if (random * tmp.edgeNums <= 1.0) {                                  tmp.state = TENTATIVELY_IN_SET;  msg.senderId = getVertexId();  msg.message = WANTS_TO_BE_IN_SET;                                  sendMessageToAllNeighbors(msg);                               }                                break;     default:      break;  }  tmp.phase = CONFLICT_RESOLUTION;          break;       case CONFLICT_RESOLUTION:                          switch (state) {                            case TENTATIVELY_IN_SET:                               if(!pmsgs->done()) {for(; ! pmsgs->done(); pmsgs->next()) {if(pmsgs->getValue().message == WANTS_TO_BE_IN_SET) {long long neighborId = pmsgs->getValue().senderId;if(neighborId < minId) {minId = neighborId;}}}if(minId == myId) {tmp.state = IN_SET;tmp.isDeleted = 1;msg.senderId = getVertexId();                                        msg.message = IS_IN_SET;sendMessageToAllNeighbors(msg);} else {tmp.state = UNKNOWN;}     } else {tmp.state = IN_SET;tmp.isDeleted = 1;                                        msg.senderId = getVertexId();                                        msg.message = IS_IN_SET;                                        sendMessageToAllNeighbors(msg);     }     break;     default:     break;          } tmp.phase = EDGE_CLEANING; break;      case EDGE_CLEANING: for(; ! pmsgs->done(); pmsgs->next()) {if(pmsgs->getValue().message == IS_IN_SET) {//tmp.target.remove(pmsgs->getValue().senderId);++numNeighborsMovedIntoSet;} } if(numNeighborsMovedIntoSet > 0) {tmp.edgeNums -= numNeighborsMovedIntoSet;tmp.state = NOT_IN_SET; } tmp.phase = COLOR_ASSIGNMENT; break;      case COLOR_ASSIGNMENT: if(state == IN_SET) {tmp.color = getSuperstep()/4;tmp.isColored = 1;accumulateAggr(0, &acc);         } else {tmp.state = UNKNOWN; } tmp.phase = LOTTERY; break;      default: break;         }switch (getValue().state) {                  case UNKNOWN:                     accumulateAggr(NUM_VERTICES_UNKNOWN, &acc);                  break;                  case TENTATIVELY_IN_SET:                     accumulateAggr(NUM_VERTICES_TENTATIVELY_IN_SET, &acc);                  break;  case NOT_IN_SET:                     accumulateAggr(NUM_VERTICES_NOT_IN_SET, &acc);                  break;                  case IN_SET:                     accumulateAggr(NUM_VERTICES_IN_SET, &acc);                  break;                  default:  break;        }}*mutableValue() = tmp;    }};class VERTEX_CLASS_NAME(Graph): public Graph {public:    VERTEX_CLASS_NAME(Aggregator)* aggregator;public:    // argv[0]: PageRankVertex.so    // argv[1]: <input path>    // argv[2]: <output path>    void init(int argc, char* argv[]) {        setNumHosts(5);        setHost(0, "localhost", 1411);        setHost(1, "localhost", 1421);        setHost(2, "localhost", 1431);        setHost(3, "localhost", 1441);        setHost(4, "localhost", 1451);        if (argc < 3) {           printf ("Usage: %s <input path> <output path>\n", argv[0]);           exit(1);        }        m_pin_path = argv[1];        m_pout_path = argv[2];phase = LOTTERY;        aggregator = new VERTEX_CLASS_NAME(Aggregator)[5];        regNumAggr(5);for(int i = 0; i < 5; i++)           regAggr(i, &aggregator[i]);    }    void term() {        delete[] aggregator;    }};/* STOP: do not change the code below. */extern "C" Graph* create_graph() {    Graph* pgraph = new VERTEX_CLASS_NAME(Graph);    pgraph->m_pin_formatter = new VERTEX_CLASS_NAME(InputFormatter);    pgraph->m_pout_formatter = new VERTEX_CLASS_NAME(OutputFormatter);    pgraph->m_pver_base = new VERTEX_CLASS_NAME();    return pgraph;}extern "C" void destroy_graph(Graph* pobject) {    delete ( VERTEX_CLASS_NAME()* )(pobject->m_pver_base);    delete ( VERTEX_CLASS_NAME(OutputFormatter)* )(pobject->m_pout_formatter);    delete ( VERTEX_CLASS_NAME(InputFormatter)* )(pobject->m_pin_formatter);    delete ( VERTEX_CLASS_NAME(Graph)* )pobject;}