2: /* fn1wd.f -- translated by f2c (version 19931217).*/

  4: #include <petsc/private/matorderimpl.h>

  6: /*****************************************************************/
  7: /********     FN1WD ..... FIND ONE-WAY DISSECTORS        *********/
  8: /*****************************************************************/
  9: /*    PURPOSE - THIS SUBROUTINE FINDS ONE-WAY DISSECTORS OF      */
 10: /*       A CONNECTED COMPONENT SPECIFIED BY MASK AND ../../...       */
 11: /*                                                               */
 12: /*    INPUT PARAMETERS -                                         */
 13: /*       ../../.. - A NODE THAT DEFINES (ALONG WITH MASK) THE        */
 14: /*              COMPONENT TO BE PROCESSED.                       */
 15: /*       (XADJ, ADJNCY) - THE ADJACENCY STRUCTURE.               */
 16: /*                                                               */
 17: /*    OUTPUT PARAMETERS -                                        */
 18: /*       NSEP - NUMBER OF NODES IN THE ONE-WAY DISSECTORS.       */
 19: /*       SEP - VECTOR CONTAINING THE DISSECTOR NODES.            */
 20: /*                                                               */
 21: /*    UPDATED PARAMETER -                                        */
 22: /*       MASK - NODES IN THE DISSECTOR HAVE THEIR MASK VALUES    */
 23: /*              SET TO ZERO.                                     */
 24: /*                                                               */
 25: /*    WORKING PARAMETERS-                                        */
 26: /*       (XLS, LS) - LEVEL STRUCTURE USED BY THE ROUTINE FN../../... */
 27: /*                                                               */
 28: /*    PROGRAM SUBROUTINE -                                       */
 29: /*       FN../../...                                                 */
 30: /*****************************************************************/
 33: PetscErrorCode SPARSEPACKfn1wd(PetscInt *root,const PetscInt *inxadj,const PetscInt *adjncy,
 34:                                PetscInt *mask, PetscInt *nsep, PetscInt *sep, PetscInt *nlvl, PetscInt *
 35:                                xls, PetscInt *ls)
 36: {
 37:   PetscInt *xadj = (PetscInt*)inxadj;   /* Used as temporary and reset */
 38:   /* System generated locals */
 39:   PetscInt i__1, i__2;

 41:   /* Local variables */
 42:   PetscInt  node, i, j, k;
 43:   PetscReal width, fnlvl;
 44:   PetscInt  kstop, kstrt, lp1beg, lp1end;
 45:   PetscReal deltp1;
 46:   PetscInt  lvlbeg, lvlend;
 47:   PetscInt  nbr, lvl;

 50:   /* Parameter adjustments */
 51:   --ls;
 52:   --xls;
 53:   --sep;
 54:   --mask;
 55:   --adjncy;
 56:   --xadj;

 58:   SPARSEPACKfnroot(root, &xadj[1], &adjncy[1], &mask[1], nlvl, &xls[1], &ls[1]);
 59:   fnlvl  = (PetscReal) (*nlvl);
 60:   *nsep  = xls[*nlvl + 1] - 1;
 61:   width  = (PetscReal) (*nsep) / fnlvl;
 62:   deltp1 = PetscSqrtReal((width * 3. + 13.) / 2.) + 1.;
 63:   if (*nsep >= 50 && deltp1 <= fnlvl * .5f) goto L300;

 65: /*       THE COMPONENT IS TOO SMALL, OR THE LEVEL STRUCTURE */
 66: /*       IS VERY LONG AND NARROW. RETURN THE WHOLE COMPONENT.*/
 67:   i__1 = *nsep;
 68:   for (i = 1; i <= i__1; ++i) {
 69:     node       = ls[i];
 70:     sep[i]     = node;
 71:     mask[node] = 0;
 72:   }
 73:   return(0);
 74: /*       FIND THE PARALLEL DISSECTORS.*/
 75: L300:
 76:   *nsep = 0;
 77:   i     = 0;
 78: L400:
 79:   ++i;
 80:   lvl = (PetscInt)((PetscReal) i * deltp1 + .5f);
 81:   if (lvl >= *nlvl) return(0);
 82:   lvlbeg = xls[lvl];
 83:   lp1beg = xls[lvl + 1];
 84:   lvlend = lp1beg - 1;
 85:   lp1end = xls[lvl + 2] - 1;
 86:   i__1   = lp1end;
 87:   for (j = lp1beg; j <= i__1; ++j) {
 88:     node       = ls[j];
 89:     xadj[node] = -xadj[node];
 90:   }
 91: /*          NODES IN LEVEL LVL ARE CHOSEN TO FORM DISSECTOR. */
 92: /*          INCLUDE ONLY THOSE WITH NEIGHBORS IN LVL+1 LEVEL. */
 93: /*          XADJ IS USED TEMPORARILY TO MARK NODES IN LVL+1.  */
 94:   i__1 = lvlend;
 95:   for (j = lvlbeg; j <= i__1; ++j) {
 96:     node  = ls[j];
 97:     kstrt = xadj[node];
 98:     kstop = (i__2 = xadj[node + 1], (PetscInt)PetscAbsInt(i__2)) - 1;
 99:     i__2  = kstop;
100:     for (k = kstrt; k <= i__2; ++k) {
101:       nbr = adjncy[k];
102:       if (xadj[nbr] > 0) goto L600;
103:       ++(*nsep);
104:       sep[*nsep] = node;
105:       mask[node] = 0;
106:       goto L700;
107: L600:
108:       ;
109:     }
110: L700:
111:     ;
112:   }
113:   i__1 = lp1end;
114:   for (j = lp1beg; j <= i__1; ++j) {
115:     node       = ls[j];
116:     xadj[node] = -xadj[node];
117:   }
118:   goto L400;
119: }