Actual source code: numsrt.c

  1: #define PETSCMAT_DLL
  2: /* numsrt.f -- translated by f2c (version of 25 March 1992  12:58:56). */

 4:  #include petsc.h
 5:  #include src/mat/color/color.h

  9: PetscErrorCode MINPACKnumsrt(PetscInt *n,PetscInt *nmax,PetscInt *num,PetscInt *mode,PetscInt *idex,PetscInt *last,PetscInt *next)
 10: {
 11:     /* System generated locals */
 12:     PetscInt i__1, i__2;

 14:     /* Local variables */
 15:     PetscInt jinc, i, j, k, l, jl, ju;

 17: /*     Given a sequence of integers, this subroutine groups */
 18: /*     together those indices with the same sequence value */
 19: /*     and, optionally, sorts the sequence into either */
 20: /*     ascending or descending order. */
 21: /*     The sequence of integers is defined by the array num, */
 22: /*     and it is assumed that the integers are each from the set */
 23: /*     0,1,...,nmax. On output the indices k such that num(k) = l */
 24: /*     for any l = 0,1,...,nmax can be obtained from the arrays */
 25: /*     last and next as follows. */
 26: /*           k = last(l) */
 27: /*           while (k .ne. 0) k = next(k) */
 28: /*     Optionally, the subroutine produces an array index so that */
 29: /*     the sequence num(index(i)), i = 1,2,...,n is sorted. */
 30: /*     The subroutine statement is */
 31: /*       subroutine numsrt(n,nmax,num,mode,index,last,next) */
 32: /*     where */
 33: /*       n is a positive integer input variable. */
 34: /*       nmax is a positive integer input variable. */
 35: /*       num is an input array of length n which contains the */
 36: /*         sequence of integers to be grouped and sorted. It */
 37: /*         is assumed that the integers are each from the set */
 38: /*         0,1,...,nmax. */
 39: /*       mode is an integer input variable. The sequence num is */
 40: /*         sorted in ascending order if mode is positive and in */
 41: /*         descending order if mode is negative. If mode is 0, */
 42: /*         no sorting is done. */
 43: /*       index is an integer output array of length n set so */
 44: /*         that the sequence */
 45: /*               num(index(i)), i = 1,2,...,n */
 46: /*         is sorted according to the setting of mode. If mode */
 47: /*         is 0, index is not referenced. */
 48: /*       last is an integer output array of length nmax + 1. The */
 49: /*         index of num for the last occurrence of l is last(l) */
 50: /*         for any l = 0,1,...,nmax unless last(l) = 0. In */
 51: /*         this case l does not appear in num. */
 52: /*       next is an integer output array of length n. If */
 53: /*         num(k) = l, then the index of num for the previous */
 54: /*         occurrence of l is next(k) for any l = 0,1,...,nmax */
 55: /*         unless next(k) = 0. In this case there is no previous */
 56: /*         occurrence of l in num. */
 57: /*     Argonne National Laboratory. MINPACK Project. July 1983. */
 58: /*     Thomas F. Coleman, Burton S. Garbow, Jorge J. More' */

 60:     /* Parameter adjustments */
 62:     --next;
 63:     --idex;
 64:     --num;

 66:     i__1 = *nmax;
 67:     for (i = 0; i <= i__1; ++i) {
 68:         last[i] = 0;
 69:     }
 70:     i__1 = *n;
 71:     for (k = 1; k <= i__1; ++k) {
 72:         l = num[k];
 73:         next[k] = last[l];
 74:         last[l] = k;
 75:     }
 76:     if (!*mode) {
 77:         return(0);
 78:     }

 80: /*     Store the pointers to the sorted array in index. */

 82:     i = 1;
 83:     if (*mode > 0) {
 84:         jl = 0;
 85:         ju = *nmax;
 86:         jinc = 1;
 87:     } else {
 88:         jl = *nmax;
 89:         ju = 0;
 90:         jinc = -1;
 91:     }
 92:     i__1 = ju;
 93:     i__2 = jinc;
 94:     for (j = jl; i__2 < 0 ? j >= i__1 : j <= i__1; j += i__2) {
 95:         k = last[j];
 96: L30:
 97:         if (!k) {
 98:             goto L40;
 99:         }
100:         idex[i] = k;
101:         ++i;
102:         k = next[k];
103:         goto L30;
104: L40:
105:         ;
106:     }
107:     return(0);
108: }