! D01UAF Example Program Text
! Mark 30.1 Release. NAG Copyright 2024.
Module d01uafe_mod
! D01UAF 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 :: d01uaf_f
! .. Parameters ..
Integer, Parameter, Public :: i_funid = 1
Integer, Parameter, Public :: liuser = i_funid
Integer, Parameter, Public :: lruser = 1
Contains
Subroutine d01uaf_f(x,nx,fv,iflag,iuser,ruser)
! .. Implicit None Statement ..
Implicit None
! .. Scalar Arguments ..
Integer, Intent (Inout) :: iflag
Integer, Intent (In) :: nx
! .. Array Arguments ..
Real (Kind=nag_wp), Intent (Out) :: fv(nx)
Real (Kind=nag_wp), Intent (Inout) :: ruser(*)
Real (Kind=nag_wp), Intent (In) :: x(nx)
Integer, Intent (Inout) :: iuser(*)
! .. Intrinsic Procedures ..
Intrinsic :: exp, log
! .. Executable Statements ..
Select Case (iuser(i_funid))
Case (1)
fv = 4.0E0_nag_wp/(1.0E0_nag_wp+x*x)
Case (2)
fv = 1.0E0_nag_wp/(x*x*log(x))
Case (3)
fv = exp(-x)/x
Case (4)
fv = 1.0E0_nag_wp/x
Case (5)
fv = exp(-3.0E0_nag_wp*x*x-4.0E0_nag_wp*x-1.0E0_nag_wp)
Case (6)
fv = exp(2.0E0_nag_wp*x+2.0E0_nag_wp)
Case Default
iflag = -1
End Select
End Subroutine d01uaf_f
End Module d01uafe_mod
Program d01uafe
! D01UAF Example Main Program
! .. Use Statements ..
Use d01uafe_mod, Only: d01uaf_f, i_funid, liuser, lruser
Use nag_library, Only: d01uaf, nag_wp
! .. Implicit None Statement ..
Implicit None
! .. Parameters ..
Integer, Parameter :: nout = 6
! .. Local Scalars ..
Real (Kind=nag_wp) :: a, b, dinest
Integer :: funid, i, ifail, key, nstor
! .. Local Arrays ..
Real (Kind=nag_wp) :: ruser(lruser)
Integer :: iuser(liuser)
! .. Executable Statements ..
Write (nout,*) 'D01UAF Example Program Results'
cases: Do funid = 1, 6
Write (nout,*)
Select Case (funid)
Case (1)
Write (nout,*) 'Gauss-Legendre example'
a = 0.0_nag_wp
b = 1.0_nag_wp
key = 0
Case (2)
Write (nout,*) 'Rational Gauss example'
a = 2.0_nag_wp
b = 0.0_nag_wp
key = -5
Case (3)
Write (nout,*) 'Gauss-Laguerre example (adjusted weights)'
a = 2.0_nag_wp
b = 1.0_nag_wp
key = -3
Case (4)
Write (nout,*) 'Gauss-Laguerre example (normal weights)'
a = 2.0_nag_wp
b = 1.0_nag_wp
key = 3
Case (5)
Write (nout,*) 'Gauss-Hermite example (adjusted weights)'
a = -1.0_nag_wp
b = 3.0_nag_wp
key = -4
Case (6)
Write (nout,*) 'Gauss-Hermite example (normal weights)'
a = -1.0_nag_wp
b = 3.0_nag_wp
key = 4
End Select
iuser(i_funid) = funid
Do i = 1, 6
nstor = 2**(i)
ifail = -1
Call d01uaf(key,a,b,nstor,d01uaf_f,dinest,iuser,ruser,ifail)
Select Case (ifail)
Case (:-1)
! Error flag returned by d01uaf_f
Exit cases
Case (0,1)
! The definite integral has been estimated.
Write (nout,99999) nstor, dinest
Case Default
! Illegal parameters on entry to d01uaf
Exit cases
End Select
End Do
Write (nout,*)
End Do cases
99999 Format (1X,I5,' Points Answer = ',F10.5)
End Program d01uafe