# dqk15.f

          SUBROUTINE DQK15 (F, A, B, RESULT, ABSERR, RESABS, RESASC)
    C***BEGIN PROLOGUE  DQK15
    C***PURPOSE  To compute I = Integral of F over (A,B), with error
    C                           estimate
    C                       J = integral of ABS(F) over (A,B)
    C***LIBRARY   SLATEC (QUADPACK)
    C***CATEGORY  H2A1A2
    C***TYPE      DOUBLE PRECISION (QK15-S, DQK15-D)
    C***KEYWORDS  15-POINT GAUSS-KRONROD RULES, QUADPACK, QUADRATURE
    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           Integration rules
    C           Standard fortran subroutine
    C           Double precision version
    C
    C           PARAMETERS
    C            ON ENTRY
    C              F      - Double precision
    C                       Function subprogram defining the integrand
    C                       FUNCTION F(X). The actual name for F needs to be
    C                       Declared E X T E R N A L in the calling program.
    C
    C              A      - Double precision
    C                       Lower limit of integration
    C
    C              B      - Double precision
    C                       Upper limit of integration
    C
    C            ON RETURN
    C              RESULT - Double precision
    C                       Approximation to the integral I
    C                       Result is computed by applying the 15-POINT
    C                       KRONROD RULE (RESK) obtained by optimal addition
    C                       of abscissae to the 7-POINT GAUSS RULE(RESG).
    C
    C              ABSERR - Double precision
    C                       Estimate of the modulus of the absolute error,
    C                       which should not exceed ABS(I-RESULT)
    C
    C              RESABS - Double precision
    C                       Approximation to the integral J
    C
    C              RESASC - Double precision
    C                       Approximation to the integral of ABS(F-I/(B-A))
    C                       over (A,B)
    C
    C***REFERENCES  (NONE)
    C***ROUTINES CALLED  D1MACH
    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***END PROLOGUE  DQK15