! D01ASF Example Program Text
! Mark 30.1 Release. NAG Copyright 2024.
Module d01asfe_mod
! D01ASF 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 :: g
! .. Parameters ..
Integer, Parameter, Public :: limlst = 50, lw = 800, nout = 6
Integer, Parameter, Public :: liw = lw/2
Contains
Function g(x)
! .. Function Return Value ..
Real (Kind=nag_wp) :: g
! .. Scalar Arguments ..
Real (Kind=nag_wp), Intent (In) :: x
! .. Intrinsic Procedures ..
Intrinsic :: sqrt
! .. Executable Statements ..
If (x>0.0E0_nag_wp) Then
g = 1.0E0_nag_wp/sqrt(x)
Else
g = 0.0E0_nag_wp
End If
Return
End Function g
End Module d01asfe_mod
Program d01asfe
! D01ASF Example Main Program
! .. Use Statements ..
Use d01asfe_mod, Only: g, limlst, liw, lw, nout
Use nag_library, Only: d01asf, nag_wp, x01aaf
! .. Implicit None Statement ..
Implicit None
! .. Local Scalars ..
Real (Kind=nag_wp) :: a, abserr, epsabs, omega, result
Integer :: ifail, key, lst
! .. Local Arrays ..
Real (Kind=nag_wp), Allocatable :: erlst(:), rslst(:), w(:)
Integer, Allocatable :: ierlst(:), iw(:)
! .. Executable Statements ..
Write (nout,*) 'D01ASF Example Program Results'
Allocate (erlst(limlst),rslst(limlst),w(lw),ierlst(limlst),iw(liw))
epsabs = 1.0E-03_nag_wp
a = 0.0E0_nag_wp
omega = 0.5E0_nag_wp*x01aaf(omega)
key = 1
ifail = -1
Call d01asf(g,a,omega,key,epsabs,result,abserr,limlst,lst,erlst,rslst, &
ierlst,w,lw,iw,liw,ifail)
If (ifail>=0) Then
Write (nout,*)
Write (nout,99999) 'A - lower limit of integration = ', a
Write (nout,*) 'B - upper limit of integration = infinity'
Write (nout,99998) 'EPSABS - absolute accuracy requested = ', epsabs
If (ifail/=6 .And. ifail/=10) 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) 'LST - number of intervals used = ', lst
Write (nout,99996) &
'IW(1) - max. no. of subintervals used in any one interval = ', &
iw(1)
End If
End If
99999 Format (1X,A,F10.4)
99998 Format (1X,A,E9.2)
99997 Format (1X,A,F9.5)
99996 Format (1X,A,I4)
End Program d01asfe