# SLATEC Routines --- DQPSRT ---

```*DECK DQPSRT
SUBROUTINE DQPSRT (LIMIT, LAST, MAXERR, ERMAX, ELIST, IORD, NRMAX)
C***BEGIN PROLOGUE  DQPSRT
C***SUBSIDIARY
C***PURPOSE  This routine maintains the descending ordering in the
C            list of the local error estimated resulting from the
C            interval subdivision process. At each call two error
C            estimates are inserted using the sequential search
C            method, top-down for the largest error estimate and
C            bottom-up for the smallest error estimate.
C***LIBRARY   SLATEC
C***TYPE      DOUBLE PRECISION (QPSRT-S, DQPSRT-D)
C***KEYWORDS  SEQUENTIAL SORTING
C***AUTHOR  Piessens, Robert
C             Applied Mathematics and Programming Division
C             K. U. Leuven
C           de Doncker, Elise
C             Applied Mathematics and Programming Division
C             K. U. Leuven
C***DESCRIPTION
C
C           Ordering routine
C           Standard fortran subroutine
C           Double precision version
C
C           PARAMETERS (MEANING AT OUTPUT)
C              LIMIT  - Integer
C                       Maximum number of error estimates the list
C                       can contain
C
C              LAST   - Integer
C                       Number of error estimates currently in the list
C
C              MAXERR - Integer
C                       MAXERR points to the NRMAX-th largest error
C                       estimate currently in the list
C
C              ERMAX  - Double precision
C                       NRMAX-th largest error estimate
C                       ERMAX = ELIST(MAXERR)
C
C              ELIST  - Double precision
C                       Vector of dimension LAST containing
C                       the error estimates
C
C              IORD   - Integer
C                       Vector of dimension LAST, the first K elements
C                       of which contain pointers to the error
C                       estimates, such that
C                       ELIST(IORD(1)),...,  ELIST(IORD(K))
C                       form a decreasing sequence, with
C                       K = LAST if LAST.LE.(LIMIT/2+2), and
C                       K = LIMIT+1-LAST otherwise
C
C              NRMAX  - Integer
C                       MAXERR = IORD(NRMAX)
C
C***ROUTINES CALLED  (NONE)
C***REVISION HISTORY  (YYMMDD)
C   800101  DATE WRITTEN
C   890831  Modified array declarations.  (WRB)
C   890831  REVISION DATE from Version 3.2
C   891214  Prologue converted to Version 4.0 format.  (BAB)
C   900328  Added TYPE section.  (WRB)
C***END PROLOGUE  DQPSRT
```