C++ TRnd类代码示例

int main() {
  TLSHash LSH(7, 7, DIM, TLSHash::EUCLIDEAN);
  LSH.Init();

  TRnd Gen;
  Gen.Randomize();

  TVec<TFltV> DataV;
  for (int i=0; i<1000000; i++) {
    TFltV Datum;
    for (int j=0; j<3; j++) {
      Datum.Add(Gen.GetUniDev()*2100);
    }
    DataV.Add(Datum);
  }
  LSH.AddV(DataV);
  
  TVec<TPair<TFltV, TFltV> > NeighborsV = LSH.GetAllCandidatePairs();
  printf("Number of Candidates: %d\n", NeighborsV.Len());

  NeighborsV = LSH.GetAllNearPairs();
  printf("Number of Close Pairs: %d\n", NeighborsV.Len());
  for (int i=0; i<NeighborsV.Len(); i++) {
    outputPoint(NeighborsV[i].GetVal1());
    printf(" ");
    outputPoint(NeighborsV[i].GetVal2());
    printf("\n");
  }
  return 0;
}

/// Generates a small-world graph using the Watts-Strogatz model.
/// We assume a circle where each node creates links to NodeOutDeg other nodes. 
/// This way at the end each node is connected to 2*NodeOutDeg other nodes.
/// See: Collective dynamics of 'small-world' networks. Watts and Strogatz.
/// URL: http://research.yahoo.com/files/w_s_NATURE_0.pdf
PUNGraph GenSmallWorld(const int& Nodes, const int& NodeOutDeg, const double& RewireProb, TRnd& Rnd) {
  THashSet<TIntPr> EdgeSet(Nodes*NodeOutDeg);
  
  IAssertR(Nodes > NodeOutDeg, TStr::Fmt("Insufficient nodes for out degree, %d!", NodeOutDeg));
  for (int node = 0; node < Nodes; node++) {
    const int src = node;
    for (int edge = 1; edge <= NodeOutDeg; edge++) {
      int dst = (node+edge) % Nodes;      // edge to next neighbor
      if (Rnd.GetUniDev() < RewireProb) { // random edge
        dst = Rnd.GetUniDevInt(Nodes);
        while (dst == src || EdgeSet.IsKey(TIntPr(src, dst))) {
          dst = Rnd.GetUniDevInt(Nodes); }
      }
      EdgeSet.AddKey(TIntPr(src, dst));
    }
  }
  PUNGraph GraphPt = TUNGraph::New();
  TUNGraph& Graph = *GraphPt;
  Graph.Reserve(Nodes, EdgeSet.Len());
  int node;
  for (node = 0; node < Nodes; node++) {
    IAssert(Graph.AddNode(node) == node);
  }
  for (int edge = 0; edge < EdgeSet.Len(); edge++) {
    Graph.AddEdge(EdgeSet[edge].Val1, EdgeSet[edge].Val2);
  }
  Graph.Defrag();
  return GraphPt;
}

PBPGraph GenRndBipart(const int& LeftNodes, const int& RightNodes, const int& Edges, TRnd& Rnd) {
  PBPGraph G = TBPGraph::New();
  for (int i = 0; i < LeftNodes; i++) { G->AddNode(i, true); }
  for (int i = 0; i < RightNodes; i++) { G->AddNode(LeftNodes+i, false); }
  IAssertR(Edges <= LeftNodes*RightNodes, "Too many edges in the bipartite graph!");
  for (int edges = 0; edges < Edges; ) {
    const int LNId = Rnd.GetUniDevInt(LeftNodes);
    const int RNId = LeftNodes + Rnd.GetUniDevInt(RightNodes);
    if (G->AddEdge(LNId, RNId) != -2) { edges++; } // is new edge
  }
  return G;
}

void TAGM::RndConnectInsideCommunity(PUNGraph& Graph, const TIntV& CmtyV, const double& Prob, TRnd& Rnd){
	int CNodes = CmtyV.Len();
	int CEdges = Rnd.GetBinomialDev(Prob,CNodes*(CNodes-1)/2);
	THashSet<TIntPr> NewEdgeSet(CEdges);
	for (int edge = 0; edge < CEdges; ) {
		int SrcNId = CmtyV[Rnd.GetUniDevInt(CNodes)];
		int DstNId = CmtyV[Rnd.GetUniDevInt(CNodes)];
		if(SrcNId>DstNId){Swap(SrcNId,DstNId);}
		if (SrcNId != DstNId && !NewEdgeSet.IsKey(TIntPr(SrcNId,DstNId))) { // is new edge
			NewEdgeSet.AddKey(TIntPr(SrcNId,DstNId));
			Graph->AddEdge(SrcNId,DstNId);
			edge++; 
		} 
	}
}

int TBPGraph::GetRndNId(TRnd& Rnd) { 
  const int NNodes = GetNodes();
  if (Rnd.GetUniDevInt(NNodes) < GetLNodes()) {
    return GetRndLNId(Rnd); }
  else {
    return GetRndRNId(Rnd); }
}

THash<TInt, TInt> * choose_seeds (const PUNGraph g, const int num, const int * infection_state, const int infect) {

  THash<TInt, TInt> choices; 
  THash<TInt, TUNGraph::TNode> nodes;
  THash<TInt, TInt> * output = new THash<TInt, TInt> ();
  TInt weight = 0;
  TInt num_total = 0;
  for (TUNGraph::TNodeI n = g->BegNI(); n != g->EndNI(); n++) {
    //cout << "nodeID: " << n.GetId() << ",\tStatus: " << infection_state[n.GetId () - 1] << endl;
    if (infection_state[n.GetId () - 1] != infect) {
      weight += n.GetDeg ();
      choices.AddDat (num_total, weight);
      nodes.AddDat (num_total, n.GetId());
      num_total++;
    }
  }
  //  TRnd random ((int) time(NULL));
  // TRnd random (0);
  TInt num_chosen = 0;
  while (num_chosen < num) {
    TInt choice = my_random.GetUniDevInt (weight);
    TUNGraph::TNode node_choice = nodes[find (choice, choices, 0,  num_total-1)];
    if (!output->IsKey(node_choice.GetId())) {
      num_chosen++;
      // cout << node_choice.GetId () << "\n";
      output->AddDat(node_choice.GetId (), 1);
    }
  }
  return output;
}

bool test(PGraph &graph, bool followOut, bool followIn) {
  printf("\n================================\nFollowOut: %d, FollowIn: %d\n", followOut, followIn);
  int iters = 10;
  for (int k = 0; k < iters; k++) {
    TRnd rnd = TRnd((int)time(0));
    int start = graph->GetRndNId(rnd);
    rnd.PutSeed(0);
//    int target = graph->GetRndNId(rnd);
//    printf("Start node: %d, target node: %d\n", start, target);
    int target = -1;
    printf("Start node: %d\n", start);

    struct timeval tv1, tv2;
    gettimeofday(&tv1, NULL);

    /* Hybrid */
    TBreathFS<PGraph> bfs_hybrid(graph, true);
    int maxDist_hybrid = bfs_hybrid.DoBfsHybrid(start, followOut, followIn, target);

    gettimeofday(&tv2, NULL);
    double time_hybrid = timeInSeconds(tv1, tv2);

    /* Original */
    gettimeofday(&tv1, NULL);

    TBreathFS<PGraph> bfs(graph, true);
    int maxDist = bfs.DoBfs(start, followOut, followIn, target);

    gettimeofday(&tv2, NULL);
    double time = timeInSeconds(tv1, tv2);

    /* Check results */
    if (maxDist_hybrid != maxDist) {
      printf("MaxDist incorrect.\n");
      return false;
    }
    if (target == -1) {
      if (!checkResults<PGraph>(bfs_hybrid, bfs)) {
        printf("NIdDistH values incorrect!\n");
        return false;
      }
    }

    printf("Execution times: Original: %.2f, Hybrid: %.2f\n", time, time_hybrid);
  }
  return true;
}

//Initialize positive embeddings
void InitPosEmb(TIntV& Vocab, int& Dimensions, TRnd& Rnd, TVVec<TFlt, int64>& SynPos) {
  SynPos = TVVec<TFlt, int64>(Vocab.Len(),Dimensions);
  for (int64 i = 0; i < SynPos.GetXDim(); i++) {
    for (int j = 0; j < SynPos.GetYDim(); j++) {
      SynPos(i,j) =(Rnd.GetUniDev()-0.5)/Dimensions;
    }
  }
}

void TLSHash::Init() {
  TRnd Gen;
  Gen.Randomize();

  for (int i=0; i<Bands*Rows; i++) {
    if (Type == JACCARD) {
      HashFuncV.Add(TPt<HashFunc>(new JaccardHash(Gen, Dim)));
    } else if (Type == COSINE) {
      HashFuncV.Add(TPt<HashFunc>(new CosineHash(Gen, Dim)));
    } else {
      HashFuncV.Add(TPt<HashFunc>(new EuclideanHash(Gen, Dim)));
    }
  }

  for (int i=0; i<Bands; i++) {
    SigBucketVHV.Add(THash<TInt, TIntV> (ExpectedSz, true));
  }
}

///Generate sequence from Power law
void TAGMUtil::GenPLSeq(TIntV& SzSeq, const int& SeqLen, const double& Alpha, TRnd& Rnd, const int& Min, const int& Max) {
    SzSeq.Gen(SeqLen, 0);
    while (SzSeq.Len() < SeqLen) {
        int Sz = (int) TMath::Round(Rnd.GetPowerDev(Alpha));
        if (Sz >= Min && Sz <= Max) {
            SzSeq.Add(Sz);
        }
    }
}

/// Generates a random scale-free network using the Copying Model.
/// The generating process operates as follows: Node u is added to a graph, it
/// selects a random node v, and with prob Beta it links to v, with 1-Beta 
/// links u links to neighbor of v. The power-law degree exponent is -1/(1-Beta).
/// See: Stochastic models for the web graph.
/// Kumar, Raghavan, Rajagopalan, Sivakumar, Tomkins, Upfal.
/// URL: http://snap.stanford.edu/class/cs224w-readings/kumar00stochastic.pdf
PNGraph GenCopyModel(const int& Nodes, const double& Beta, TRnd& Rnd) {
  PNGraph GraphPt = TNGraph::New();
  TNGraph& Graph = *GraphPt;
  Graph.Reserve(Nodes, Nodes);
  const int startNId = Graph.AddNode();
  Graph.AddEdge(startNId, startNId);
  for (int n = 1; n < Nodes; n++) {
    const int rnd = Graph.GetRndNId();
    const int NId = Graph.AddNode();
    if (Rnd.GetUniDev() < Beta) {
      Graph.AddEdge(NId, rnd); }
    else {
      const TNGraph::TNodeI NI = Graph.GetNI(rnd);
      const int rnd2 = Rnd.GetUniDevInt(NI.GetOutDeg());
      Graph.AddEdge(NId, NI.GetOutNId(rnd2));
    }
  }
  return GraphPt;
}

/// Sample random point from the surface of a Dim-dimensional unit sphere.
void GetSphereDev(const int& Dim, TRnd& Rnd, TFltV& ValV) {
  if (ValV.Len() != Dim) { ValV.Gen(Dim); }
  double Length = 0.0;
  for (int i = 0; i < Dim; i++) {
    ValV[i] = Rnd.GetNrmDev();
    Length += TMath::Sqr(ValV[i]); }
  Length = 1.0 / sqrt(Length);
  for (int i = 0; i < Dim; i++) {
    ValV[i] *= Length;
  }
}

/// Generates a random undirect graph with a given degree sequence DegSeqV.
/// Configuration model operates as follows. For each node N, of degree
/// DeqSeqV[N] we create DeqSeqV[N] spokes (half-edges). We then pick two
/// spokes at random, and connect the spokes endpoints. We continue this
/// process until no spokes are left. Generally this generates a multigraph
/// (i.e., spokes out of same nodes can be chosen multiple times).We ignore
/// (discard) self-loops and multiple edges. Thus, the generated graph will
/// only approximate follow the given degree sequence. The method is very fast!
PUNGraph GenConfModel(const TIntV& DegSeqV, TRnd& Rnd) {
  const int Nodes = DegSeqV.Len();
  PUNGraph GraphPt = TUNGraph::New();
  TUNGraph& Graph = *GraphPt;
  Graph.Reserve(Nodes, -1);
  TIntV NIdDegV(DegSeqV.Len(), 0);
  int DegSum=0, edges=0;
  for (int node = 0; node < Nodes; node++) {
    Graph.AddNode(node);
    for (int d = 0; d < DegSeqV[node]; d++) { NIdDegV.Add(node); }
    DegSum += DegSeqV[node];
  }
  NIdDegV.Shuffle(Rnd);
  TIntPrSet EdgeH(DegSum/2); // set of all edges, is faster than graph edge lookup
  if (DegSum % 2 != 0) {
    printf("Seg seq is odd [%d]: ", DegSeqV.Len());
    for (int d = 0; d < TMath::Mn(100, DegSeqV.Len()); d++) { printf("  %d", (int)DegSeqV[d]); }
    printf("\n");
  }
  int u=0, v=0;
  for (int c = 0; NIdDegV.Len() > 1; c++) {
    u = Rnd.GetUniDevInt(NIdDegV.Len());
    while ((v = Rnd.GetUniDevInt(NIdDegV.Len())) == u) { }
    if (u > v) { Swap(u, v); }
    const int E1 = NIdDegV[u];
    const int E2 = NIdDegV[v];
    if (v == NIdDegV.Len()-1) { NIdDegV.DelLast(); } 
    else { NIdDegV[v] = NIdDegV.Last();  NIdDegV.DelLast(); }
    if (u == NIdDegV.Len()-1) { NIdDegV.DelLast(); } 
    else { NIdDegV[u] = NIdDegV.Last();  NIdDegV.DelLast(); }
    if (E1 == E2 || EdgeH.IsKey(TIntPr(E1, E2))) { continue; }
    EdgeH.AddKey(TIntPr(E1, E2));
    Graph.AddEdge(E1, E2);
    edges++;
    if (c % (DegSum/100+1) == 0) { printf("\r configuration model: iter %d: edges: %d, left: %d", c, edges, NIdDegV.Len()/2); }
  }
  printf("\n");
  return GraphPt;
}

PGraph GenRndGnm(const int& Nodes, const int& Edges, const bool& IsDir, TRnd& Rnd) {
  PGraph GraphPt = PGraph::New();
  typename PGraph::TObj& Graph = *GraphPt;
  Graph.Reserve(Nodes, Edges);
  for (int node = 0; node < Nodes; node++) {
    IAssert(Graph.AddNode(node) == node);
  }
  for (int edge = 0; edge < Edges; ) {
    const int SrcNId = Rnd.GetUniDevInt(Nodes);
    const int DstNId = Rnd.GetUniDevInt(Nodes);
    if (SrcNId != DstNId && Graph.AddEdge(SrcNId, DstNId) != -2) {
      if (! IsDir) { Graph.AddEdge(DstNId, SrcNId); }
      edge++;
    }
  }
  return GraphPt;
}

/// Generates a random scale-free graph using the Geometric Preferential
/// Attachment model by Flexman, Frieze and Vera.
/// See: A geometric preferential attachment model of networks by Flexman,
/// Frieze and Vera. WAW 2004.
/// URL: http://math.cmu.edu/~af1p/Texfiles/GeoWeb.pdf
PUNGraph GenGeoPrefAttach(const int& Nodes, const int& OutDeg, const double& Beta, TRnd& Rnd) {
  PUNGraph G = TUNGraph::New(Nodes, Nodes*OutDeg);
  TFltTrV PointV(Nodes, 0);
  TFltV ValV;
  // points on a sphere of radius 1/(2*pi)
  const double Rad = 0.5 * TMath::Pi;
  for (int i = 0; i < Nodes; i++) {
    TSnapDetail::GetSphereDev(3, Rnd, ValV);
    PointV.Add(TFltTr(Rad*ValV[0], Rad*ValV[1], Rad*ValV[2]));
  }
  const double R2 = TMath::Sqr(log((double) Nodes) / (pow((double) Nodes, 0.5-Beta)));
  TIntV DegV, NIdV;
  int SumDeg;
  for (int t = 0; t < Nodes; t++) {
    const int pid = t;
    const TFltTr& P1 = PointV[pid];
    // add node
    if (! G->IsNode(pid)) { G->AddNode(pid); }
    // find neighborhood
    DegV.Clr(false);  NIdV.Clr(false);  SumDeg=0;
    for (int p = 0; p < t; p++) {
      const TFltTr& P2 = PointV[p];
      if (TMath::Sqr(P1.Val1-P2.Val1)+TMath::Sqr(P1.Val2-P2.Val2)+TMath::Sqr(P1.Val3-P2.Val3) < R2) {
        NIdV.Add(p);
        DegV.Add(G->GetNI(p).GetDeg()+1);
        SumDeg += DegV.Last();
      }
    }
    // add edges
    for (int m = 0; m < OutDeg; m++) {
      const int rnd = Rnd.GetUniDevInt(SumDeg);
      int sum = 0, dst = -1;
      for (int s = 0; s < DegV.Len(); s++) {
        sum += DegV[s];
        if (rnd < sum) { dst=s;  break; }
      }
      if (dst != -1) {
        G->AddEdge(pid, NIdV[dst]);
        SumDeg -= DegV[dst];
        NIdV.Del(dst);  DegV.Del(dst);
      }
    }
  }
  return G;
}