dqk51.f
SUBROUTINE DQK51 (F, A, B, RESULT, ABSERR, RESABS, RESASC)
C***BEGIN PROLOGUE DQK51
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 (QK51-S, DQK51-D)
C***KEYWORDS 51-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 subroutine 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 51-point
C Kronrod rule (RESK) obtained by optimal addition
C of abscissae to the 25-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 910819 Added WGK(26) to code. (WRB)
C***END PROLOGUE DQK51