Date: 2021-03-03T22:26:43+00:00

Actual source code: degree.c
petsc-3.14.5 2021-03-03
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      2: /* degree.f -- translated by f2c (version 19931217).*/

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

      6: /*****************************************************************/
      7: /*********     DEGREE ..... DEGREE IN MASKED COMPONENT   *********/
      8: /*****************************************************************/

     10: /*    PURPOSE - THIS ROUTINE COMPUTES THE DEGREES OF THE NODES*/
     11: /*       IN THE CONNECTED COMPONENT SPECIFIED BY MASK AND ../../..*/
     12: /*       NODES FOR WHICH MASK IS ZERO ARE IGNORED.*/

     14: /*    INPUT PARAMETER -*/
     15: /*       ../../.. - IS THE INPUT NODE THAT DEFINES THE COMPONENT.*/
     16: /*       (XADJ, ADJNCY) - ADJACENCY STRUCTURE PAIR.*/
     17: /*       MASK - SPECIFIES A SECTION SUBGRAPH.*/

     19: /*    OUTPUT PARAMETERS -*/
     20: /*       DEG - ARRAY CONTAINING THE DEGREES OF THE NODES IN*/
     21: /*             THE COMPONENT.*/
     22: /*       CCSIZE-SIZE OF THE COMPONENT SPECIFED BY MASK AND ../../..*/
     23: /*    WORKING PARAMETER -*/
     24: /*       LS - A TEMPORARY VECTOR USED TO STORE THE NODES OF THE*/
     25: /*              COMPONENT LEVEL BY LEVEL.*/
     26: /*****************************************************************/
     27: PetscErrorCode SPARSEPACKdegree(const PetscInt *root,const PetscInt *inxadj,const PetscInt *adjncy,PetscInt *mask,PetscInt *deg,PetscInt *ccsize,PetscInt *ls)
     28: {
     29:   PetscInt *xadj = (PetscInt*)inxadj; /* Used as temporary and reset within this function */
     30:   /* System generated locals */
     31:   PetscInt i__1,i__2;

     33:   /* Local variables */
     34:   PetscInt ideg,node,i,j,jstop,jstrt,lbegin,lvlend,lvsize,nbr;
     35: /*       INITIALIZATION ...*/
     36: /*       THE ARRAY XADJ IS USED AS A TEMPORARY MARKER TO*/
     37: /*       INDICATE WHICH NODES HAVE BEEN CONSIDERED SO FAR.*/

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

     47:   ls[1]       = *root;
     48:   xadj[*root] = -xadj[*root];
     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: L100:
     54:   lbegin = lvlend + 1;
     55:   lvlend = *ccsize;
     56: /*       FIND THE DEGREES OF NODES IN THE CURRENT LEVEL,*/
     57: /*       AND AT THE SAME TIME, GENERATE THE NEXT LEVEL.*/
     58:   i__1 = lvlend;
     59:   for (i = lbegin; i <= i__1; ++i) {
     60:     node  = ls[i];
     61:     jstrt = -xadj[node];
     62:     i__2  = xadj[node + 1];
     63:     jstop = (PetscInt)PetscAbsInt(i__2) - 1;
     64:     ideg  = 0;
     65:     if (jstop < jstrt) goto L300;
     66:     i__2 = jstop;
     67:     for (j = jstrt; j <= i__2; ++j) {
     68:       nbr = adjncy[j];
     69:       if (!mask[nbr]) goto L200;
     70:       ++ideg;
     71:       if (xadj[nbr] < 0) goto L200;
     72:       xadj[nbr] = -xadj[nbr];
     73:       ++(*ccsize);
     74:       ls[*ccsize] = nbr;
     75: L200:
     76:       ;
     77:     }
     78: L300:
     79:     deg[node] = ideg;
     80:   }
     81: /*       COMPUTE THE CURRENT LEVEL WIDTH. */
     82: /*       IF IT IS NONZERO, GENERATE ANOTHER LEVEL.*/
     83:   lvsize = *ccsize - lvlend;
     84:   if (lvsize > 0) goto L100;
     85: /*       RESET XADJ TO ITS CORRECT SIGN AND RETURN. */
     86: /*       ------------------------------------------*/
     87:   i__1 = *ccsize;
     88:   for (i = 1; i <= i__1; ++i) {
     89:     node       = ls[i];
     90:     xadj[node] = -xadj[node];
     91:   }
     92:   return(0);
     93: }