! C05AU_P0W_F Example Program Text
! Mark 30.1 Release. NAG Copyright 2024.
Module c05au_p0w_fe_mod
! C05AU_P0W_F Example Program Module:
! Parameters and User-defined Routines
! .. Use Statements ..
Use iso_c_binding, Only: c_ptr
Use nag_library, Only: nag_wp
! .. Implicit None Statement ..
Implicit None
! .. Accessibility Statements ..
Private
Public :: f
! .. Parameters ..
Integer, Parameter, Public :: nout = 6
! .. Local Scalars ..
Real (Kind=nag_wp), Public, Save :: t
Contains
Subroutine f(ad_handle,x,z,iuser,ruser)
! .. Scalar Arguments ..
Type (c_ptr), Intent (Inout) :: ad_handle
Real (Kind=nag_wp), Intent (In) :: x
Real (Kind=nag_wp), Intent (Out) :: z
! .. Array Arguments ..
Real (Kind=nag_wp), Intent (Inout) :: ruser(*)
Integer, Intent (Inout) :: iuser(*)
! .. Intrinsic Procedures ..
Intrinsic :: exp
! .. Executable Statements ..
z = x - exp(-t*x)
Return
End Subroutine f
End Module c05au_p0w_fe_mod
Program c05au_p0w_fe
! C05AU_P0W_F Example Main Program
! .. Use Statements ..
Use c05au_p0w_fe_mod, Only: f, nout, t
Use iso_c_binding, Only: c_ptr
Use nagad_library, Only: c05au_p0w_f
Use nag_library, Only: nag_wp
! .. Implicit None Statement ..
Implicit None
! .. Local Scalars ..
Type (c_ptr) :: ad_handle
Real (Kind=nag_wp) :: a, b, eps, eta, h, x
Integer :: ifail
! .. Local Arrays ..
Real (Kind=nag_wp) :: ruser(1)
Integer :: iuser(1)
! .. Executable Statements ..
Write (nout,*) 'C05AU_P0W_F Example Program Results'
t = 1.0E0_nag_wp
x = 1.0E0_nag_wp
h = 0.1E0_nag_wp
eps = 1.0E-5_nag_wp
eta = 0.0E0_nag_wp
ifail = -1
Call c05au_p0w_f(ad_handle,x,h,eps,eta,f,a,b,iuser,ruser,ifail)
Write (nout,*)
Select Case (ifail)
Case (0)
Write (nout,99999) 'Root is ', x
Write (nout,99998) 'Interval searched is [', a, ',', b, ']'
Case (3,4)
Write (nout,99999) 'Final value = ', x
Case Default
Write (nout,99997) 'The routine has failed with ifail = ', ifail
Go To 100
End Select
100 Continue
99999 Format (1X,A,F13.5)
99998 Format (1X,A,2(F8.5,A))
99997 Format (1X,A,I0)
End Program c05au_p0w_fe