1 2 SUBROUTINE DQC25C(F,A,B,C,RESULT,ABSERR,KRUL,NEVAL) 3C***BEGIN PROLOGUE DQC25C 4C***DATE WRITTEN 810101 (YYMMDD) 5C***REVISION DATE 830518 (YYMMDD) 6C***CATEGORY NO. H2A2A2,J4 7C***KEYWORDS 25-POINT CLENSHAW-CURTIS INTEGRATION 8C***AUTHOR PIESSENS, ROBERT, APPLIED MATH. AND PROGR. DIV. - 9C K. U. LEUVEN 10C DE DONCKER, ELISE, APPLIED MATH. AND PROGR. DIV. - 11C K. U. LEUVEN 12C***PURPOSE To compute I = Integral of F*W over (A,B) with 13C error estimate, where W(X) = 1/(X-C) 14C***DESCRIPTION 15C 16C Integration rules for the computation of CAUCHY 17C PRINCIPAL VALUE integrals 18C Standard fortran subroutine 19C Double precision version 20C 21C PARAMETERS 22C F - Double precision 23C Function subprogram defining the integrand function 24C F(X). The actual name for F needs to be declared 25C E X T E R N A L in the driver program. 26C 27C A - Double precision 28C Left end point of the integration interval 29C 30C B - Double precision 31C Right end point of the integration interval, B.GT.A 32C 33C C - Double precision 34C Parameter in the WEIGHT function 35C 36C RESULT - Double precision 37C Approximation to the integral 38C result is computed by using a generalized 39C Clenshaw-Curtis method if C lies within ten percent 40C of the integration interval. In the other case the 41C 15-point Kronrod rule obtained by optimal addition 42C of abscissae to the 7-point Gauss rule, is applied. 43C 44C ABSERR - Double precision 45C Estimate of the modulus of the absolute error, 46C which should equal or exceed ABS(I-RESULT) 47C 48C KRUL - Integer 49C Key which is decreased by 1 if the 15-point 50C Gauss-Kronrod scheme has been used 51C 52C NEVAL - Integer 53C Number of integrand evaluations 54C 55C ...................................................................... 56C***REFERENCES (NONE) 57C***ROUTINES CALLED DQCHEB,DQK15W,DQWGTC 58C***END PROLOGUE DQC25C 59 60 61