! D01AKF Example Program Text
! Mark 28.4 Release. NAG Copyright 2022.
Module d01akfe_mod
! D01AKF Example Program Module:
! Parameters and User-defined Routines
! .. Use Statements ..
Use nag_library, Only: nag_wp
! .. Implicit None Statement ..
Implicit None
! .. Accessibility Statements ..
Private
Public :: f
! .. Parameters ..
Integer, Parameter, Public :: lw = 800, nout = 6
Integer, Parameter, Public :: liw = lw/4
Contains
Function f(x)
! .. Function Return Value ..
Real (Kind=nag_wp) :: f
! .. Scalar Arguments ..
Real (Kind=nag_wp), Intent (In) :: x
! .. Intrinsic Procedures ..
Intrinsic :: cos, sin
! .. Executable Statements ..
f = x*(sin(30.0E0_nag_wp*x))*cos(x)
Return
End Function f
End Module d01akfe_mod
Program d01akfe
! D01AKF Example Main Program
! .. Use Statements ..
Use d01akfe_mod, Only: f, liw, lw, nout
Use nag_library, Only: d01akf, nag_wp, x01aaf
! .. Implicit None Statement ..
Implicit None
! .. Local Scalars ..
Real (Kind=nag_wp) :: a, abserr, b, epsabs, epsrel, pi, &
result
Integer :: ifail
! .. Local Arrays ..
Real (Kind=nag_wp), Allocatable :: w(:)
Integer, Allocatable :: iw(:)
! .. Executable Statements ..
Write (nout,*) 'D01AKF Example Program Results'
Allocate (w(lw),iw(liw))
pi = x01aaf(pi)
epsabs = 0.0E0_nag_wp
epsrel = 1.0E-03_nag_wp
a = 0.0E0_nag_wp
b = 2.0E0_nag_wp*pi
ifail = -1
Call d01akf(f,a,b,epsabs,epsrel,result,abserr,w,lw,iw,liw,ifail)
If (ifail>=0) Then
Write (nout,*)
Write (nout,99999) 'A ', 'lower limit of integration', a
Write (nout,99999) 'B ', 'upper limit of integration', b
Write (nout,99998) 'EPSABS', 'absolute accuracy requested', epsabs
Write (nout,99998) 'EPSREL', 'relative accuracy requested', epsrel
End If
If (ifail>=0 .And. ifail<=3) Then
Write (nout,*)
Write (nout,99997) 'RESULT', 'approximation to the integral', result
Write (nout,99998) 'ABSERR', 'estimate of the absolute error', abserr
Write (nout,99996) 'IW(1) ', 'number of subintervals used', iw(1)
End If
99999 Format (1X,A6,' - ',A32,' = ',F10.4)
99998 Format (1X,A6,' - ',A32,' = ',E9.2)
99997 Format (1X,A6,' - ',A32,' = ',F9.5)
99996 Format (1X,A6,' - ',A32,' = ',I4)
End Program d01akfe