SLATEC Routines --- QC25C ---

*DECK QC25C
      SUBROUTINE QC25C (F, A, B, C, RESULT, ABSERR, KRUL, NEVAL)
C***BEGIN PROLOGUE  QC25C
C***PURPOSE  To compute I = Integral of F*W over (A,B) with
C            error estimate, where W(X) = 1/(X-C)
C***LIBRARY   SLATEC (QUADPACK)
C***CATEGORY  H2A2A2, J4
C***TYPE      SINGLE PRECISION (QC25C-S, DQC25C-D)
C***KEYWORDS  25-POINT CLENSHAW-CURTIS INTEGRATION, 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 for the computation of CAUCHY
C        PRINCIPAL VALUE integrals
C        Standard fortran subroutine
C        Real version
C
C        PARAMETERS
C           F      - Real
C                    Function subprogram defining the integrand function
C                    F(X). The actual name for F needs to be declared
C                    E X T E R N A L  in the driver program.
C
C           A      - Real
C                    Left end point of the integration interval
C
C           B      - Real
C                    Right end point of the integration interval, B.GT.A
C
C           C      - Real
C                    Parameter in the WEIGHT function
C
C           RESULT - Real
C                    Approximation to the integral
C                    result is computed by using a generalized
C                    Clenshaw-Curtis method if C lies within ten percent
C                    of the integration interval. In the other case the
C                    15-point Kronrod rule obtained by optimal addition
C                    of abscissae to the 7-point Gauss rule, is applied.
C
C           ABSERR - Real
C                    Estimate of the modulus of the absolute error,
C                    which should equal or exceed ABS(I-RESULT)
C
C           KRUL   - Integer
C                    Key which is decreased by 1 if the 15-point
C                    Gauss-Kronrod scheme has been used
C
C           NEVAL  - Integer
C                    Number of integrand evaluations
C
C***REFERENCES  (NONE)
C***ROUTINES CALLED  QCHEB, QK15W, QWGTC
C***REVISION HISTORY  (YYMMDD)
C   810101  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  QC25C