proj/mag/harp/libs/matlab/mfile-mex/assignment/readgraph.c

/* set up data structures for weighted match */

/* to add a new type, add new case in SetUp() and a Set_X() routine */

SetUp (void * gptr, int type)
{
  int i         = 0;
  int allocsize = 0;

  Graph g          = (Graph)       NULL;
  EuclidGraph xy   = (EuclidGraph) NULL;
  MatrixGraph matg = (MatrixGraph) NULL;

  if ( type==1 )
  {
    g = (Graph) gptr;
    U = Degree(g,0);
    V = NumEdges(g);
    }
  else if (type==2)
  {
    xy = (EuclidGraph) gptr;
    U = xy[0][0];
    V = U * (U - 1) / 2;
    }
  else if (type==3)
  {
    matg = (MatrixGraph) gptr;
    U    = matg[0];
    V    = U * (U - 1) / 2;
    }

  allocsize = (U + 2 * V + 2) * sizeof(int);

#ifdef MATLAB_MEX_FILE
  void *mxMalloc(size_t);
  A         = (int *) mxMalloc(allocsize);
  END       = (int *) mxMalloc(allocsize);
  WEIGHT    = (int *) mxMalloc(allocsize);
#else
  A         = (int *) malloc(allocsize);
  END       = (int *) malloc(allocsize);
  WEIGHT    = (int *) malloc(allocsize);
#endif

  for (i = 0; i < U + 2 * V + 2; i++)
  {
    A[i] = END[i] = WEIGHT[i] = 0;
  }


  if (type == 1)
  {
    SetStandard(g);
  }
  else if (type == 2)
  {
    SetEuclid(xy);
  }
  else if (type == 3)
  {
    SetMatrix(matg);
  }
}


/* set up from Type 1 graph. */

SetStandard(graph)
Graph graph;
{   int elabel, adj_node, i, j;
    int u, v, currentedge;
    Edge edge;

    currentedge = U+2;
    for (i=1; i<=U; ++i) {
    edge = FirstEdge(graph,i);
    for (j = 1; j <= Degree(graph,i); ++j) {
        adj_node = EndPoint(edge);
        if (i < adj_node) {
        elabel = ELabel(edge)*2;
        WEIGHT[currentedge-1] = WEIGHT[currentedge] = 2*elabel;
        END[currentedge-1] = i;
        END[currentedge] = adj_node;
        if (A[i] == 0)
            A[i] = currentedge;
        else {
            u = i;
            v = A[i];
            while (v != 0) {
            if (END[v] > adj_node)
                break;
            u = v;
            v = A[v];
            }
            A[u] = currentedge;
            A[currentedge] = v;
            }
        u = adj_node;
        v = A[u];
        while (v != 0) {
            u = v;
            v = A[v];
            }
        A[u] = currentedge - 1;
        currentedge += 2;
        }
        edge = NextEdge(edge);
        }
    }
}

/* set up from Euclidean graph */

SetEuclid(graph)
EuclidGraph graph;
{   int i,j,currentedge;

    currentedge = U+2;

    for (i=U; i>=1; --i) 
    for (j = i-1; j >= 1; --j) {
        WEIGHT[currentedge-1] = WEIGHT[currentedge]
            = 2*eucdist2(graph,i,j);
        END[currentedge-1] = i;
        END[currentedge] = j;
        A[currentedge] = A[i];
        A[i] = currentedge;
        A[currentedge-1] = A[j];
        A[j] = currentedge-1;
        currentedge += 2;
        }
}

SetMatrix(graph)
MatrixGraph graph;
{   int i,j,currentedge;

    currentedge = U+2;

    for (i=U; i>=1; --i) 
    for (j = i-1; j >= 1; --j) {
        WEIGHT[currentedge-1] = WEIGHT[currentedge]
            = 2*graph[j*U+i];
        END[currentedge-1] = i;
        END[currentedge] = j;
        A[currentedge] = A[i];
        A[i] = currentedge;
        A[currentedge-1] = A[j];
        A[j] = currentedge-1;
        currentedge += 2;
        }
}

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