Actual source code: fn1wd.c

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

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

  5: /*****************************************************************/
  6: /********     FN1WD ..... FIND ONE-WAY DISSECTORS        *********/
  7: /*****************************************************************/
  8: /*    PURPOSE - THIS SUBROUTINE FINDS ONE-WAY DISSECTORS OF      */
  9: /*       A CONNECTED COMPONENT SPECIFIED BY MASK AND ROOT.       */
 10: /*                                                               */
 11: /*    INPUT PARAMETERS -                                         */
 12: /*       ROOT - A NODE THAT DEFINES (ALONG WITH MASK) THE        */
 13: /*              COMPONENT TO BE PROCESSED.                       */
 14: /*       (XADJ, ADJNCY) - THE ADJACENCY STRUCTURE.               */
 15: /*                                                               */
 16: /*    OUTPUT PARAMETERS -                                        */
 17: /*       NSEP - NUMBER OF NODES IN THE ONE-WAY DISSECTORS.       */
 18: /*       SEP - VECTOR CONTAINING THE DISSECTOR NODES.            */
 19: /*                                                               */
 20: /*    UPDATED PARAMETER -                                        */
 21: /*       MASK - NODES IN THE DISSECTOR HAVE THEIR MASK VALUES    */
 22: /*              SET TO ZERO.                                     */
 23: /*                                                               */
 24: /*    WORKING PARAMETERS-                                        */
 25: /*       (XLS, LS) - LEVEL STRUCTURE USED BY THE ROUTINE FNROOT. */
 26: /*                                                               */
 27: /*    PROGRAM SUBROUTINE -                                       */
 28: /*       FNROOT.                                                 */
 29: /*****************************************************************/
 30: PetscErrorCode SPARSEPACKfn1wd(PetscInt *root, const PetscInt *inxadj, const PetscInt *adjncy, PetscInt *mask, PetscInt *nsep, PetscInt *sep, PetscInt *nlvl, PetscInt *xls, PetscInt *ls)
 31: {
 32:   PetscInt *xadj = (PetscInt *)inxadj; /* Used as temporary and reset */
 33:   /* System generated locals */
 34:   PetscInt i__1, i__2;

 36:   /* Local variables */
 37:   PetscInt  node, i, j, k;
 38:   PetscReal width, fnlvl;
 39:   PetscInt  kstop, kstrt, lp1beg, lp1end;
 40:   PetscReal deltp1;
 41:   PetscInt  lvlbeg, lvlend;
 42:   PetscInt  nbr, lvl;

 44:   PetscFunctionBegin;
 45:   /* Parameter adjustments */
 46:   --ls;
 47:   --xls;
 48:   --sep;
 49:   --mask;
 50:   --adjncy;
 51:   --xadj;

 53:   PetscCall(SPARSEPACKfnroot(root, &xadj[1], &adjncy[1], &mask[1], nlvl, &xls[1], &ls[1]));
 54:   fnlvl  = (PetscReal)(*nlvl);
 55:   *nsep  = xls[*nlvl + 1] - 1;
 56:   width  = (PetscReal)(*nsep) / fnlvl;
 57:   deltp1 = PetscSqrtReal((width * 3. + 13.) / 2.) + 1.;
 58:   if (*nsep >= 50 && deltp1 <= fnlvl * .5f) goto L300;

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