# qelg.f

          SUBROUTINE QELG (N, EPSTAB, RESULT, ABSERR, RES3LA, NRES)
    C***BEGIN PROLOGUE  QELG
    ....
    ....
    Warning:   this routine is not intended to be user-callable.
    ....
    ....
    C***SUBSIDIARY
    C***PURPOSE  The routine determines the limit of a given sequence of
    C            approximations, by means of the Epsilon algorithm of
    C            P. Wynn. An estimate of the absolute error is also given.
    C            The condensed Epsilon table is computed. Only those
    C            elements needed for the computation of the next diagonal
    C            are preserved.
    C***LIBRARY   SLATEC
    C***TYPE      SINGLE PRECISION (QELG-S, DQELG-D)
    C***KEYWORDS  CONVERGENCE ACCELERATION, EPSILON ALGORITHM, EXTRAPOLATION
    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           Epsilon algorithm
    C           Standard fortran subroutine
    C           Real version
    C
    C           PARAMETERS
    C              N      - Integer
    C                       EPSTAB(N) contains the new element in the
    C                       first column of the epsilon table.
    C
    C              EPSTAB - Real
    C                       Vector of dimension 52 containing the elements
    C                       of the two lower diagonals of the triangular
    C                       epsilon table. The elements are numbered
    C                       starting at the right-hand corner of the
    C                       triangle.
    C
    C              RESULT - Real
    C                       Resulting approximation to the integral
    C
    C              ABSERR - Real
    C                       Estimate of the absolute error computed from
    C                       RESULT and the 3 previous results
    C
    C              RES3LA - Real
    C                       Vector of dimension 3 containing the last 3
    C                       results
    C
    C              NRES   - Integer
    C                       Number of calls to the routine
    C                       (should be zero at first call)
    C
    C***SEE ALSO  QAGIE, QAGOE, QAGPE, QAGSE
    C***ROUTINES CALLED  R1MACH
    C***REVISION HISTORY  (YYMMDD)
    C   800101  DATE WRITTEN
    C   890531  Changed all specific intrinsics to generic.  (WRB)
    C   890531  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  QELG