Actual source code: rootls.c

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

 3:  #include petsc.h

  5: /*****************************************************************/
  6: /*********     ../../..LS ..... ../../..ED LEVEL STRUCTURE      **********/
  7: /*****************************************************************/
  8: /*    PURPOSE - ../../..LS GENERATES THE LEVEL STRUCTURE ../../..ED */
  9: /*       AT THE INPUT NODE CALLED ../../... ONLY THOSE NODES FOR*/
 10: /*       WHICH MASK IS NONZERO WILL BE CONSIDERED.*/
 11: /*                                                */
 12: /*    INPUT PARAMETERS -                          */
 13: /*       ../../.. - THE NODE AT WHICH THE LEVEL STRUCTURE IS TO*/
 14: /*              BE ../../..ED.*/
 15: /*       (XADJ, ADJNCY) - ADJACENCY STRUCTURE PAIR FOR THE*/
 16: /*              GIVEN GRAPH.*/
 17: /*       MASK - IS USED TO SPECIFY A SECTION SUBGRAPH. NODES*/
 18: /*              WITH MASK(I)=0 ARE IGNORED.*/
 19: /*    OUTPUT PARAMETERS -*/
 20: /*       NLVL - IS THE NUMBER OF LEVELS IN THE LEVEL STRUCTURE.*/
 21: /*       (XLS, LS) - ARRAY PAIR FOR THE ../../..ED LEVEL STRUCTURE.*/
 22: /*****************************************************************/
 25: PetscErrorCode SPARSEPACKrootls(PetscInt *root, PetscInt *xadj, PetscInt *adjncy, 
 26:         PetscInt *mask, PetscInt *nlvl, PetscInt *xls, PetscInt *ls)
 27: {
 28:     /* System generated locals */
 29:     PetscInt i__1, i__2;

 31:     /* Local variables */
 32:     PetscInt node, i, j, jstop, jstrt, lbegin, ccsize, lvlend, lvsize,
 33:             nbr;

 35: /*       INITIALIZATION ...*/


 39:     /* Parameter adjustments */
 40:     --ls;
 41:     --xls;
 42:     --mask;
 43:     --adjncy;
 44:     --xadj;

 46:     mask[*root] = 0;
 47:     ls[1] = *root;
 48:     *nlvl = 0;
 49:     lvlend = 0;
 50:     ccsize = 1;
 51: /*       LBEGIN IS THE POINTER TO THE BEGINNING OF THE CURRENT*/
 52: /*       LEVEL, AND LVLEND POINTS TO THE END OF THIS LEVEL.*/
 53: L200:
 54:     lbegin = lvlend + 1;
 55:     lvlend = ccsize;
 56:     ++(*nlvl);
 57:     xls[*nlvl] = lbegin;
 58: /*       GENERATE THE NEXT LEVEL BY FINDING ALL THE MASKED */
 59: /*       NEIGHBORS OF NODES IN THE CURRENT LEVEL.*/
 60:     i__1 = lvlend;
 61:     for (i = lbegin; i <= i__1; ++i) {
 62:         node = ls[i];
 63:         jstrt = xadj[node];
 64:         jstop = xadj[node + 1] - 1;
 65:         if (jstop < jstrt) {
 66:             goto L400;
 67:         }
 68:         i__2 = jstop;
 69:         for (j = jstrt; j <= i__2; ++j) {
 70:             nbr = adjncy[j];
 71:             if (!mask[nbr]) {
 72:                 goto L300;
 73:             }
 74:             ++ccsize;
 75:             ls[ccsize] = nbr;
 76:             mask[nbr] = 0;
 77: L300:
 78:             ;
 79:         }
 80: L400:
 81:         ;
 82:     }
 83: /*       COMPUTE THE CURRENT LEVEL WIDTH.*/
 84: /*       IF IT IS NONZERO, GENERATE THE NEXT LEVEL.*/
 85:     lvsize = ccsize - lvlend;
 86:     if (lvsize > 0) {
 87:         goto L200;
 88:     }
 89: /*       RESET MASK TO ONE FOR THE NODES IN THE LEVEL STRUCTURE.*/
 90:     xls[*nlvl + 1] = lvlend + 1;
 91:     i__1 = ccsize;
 92:     for (i = 1; i <= i__1; ++i) {
 93:         node = ls[i];
 94:         mask[node] = 1;
 95:     }
 96:     return(0);
 97: }