! D01FBF Example Program Text
! Mark 30.1 Release. NAG Copyright 2024.
Module d01fbfe_mod
! D01FBF 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 :: ndim = 4, nout = 6
Contains
Function f(ndim,x)
! .. Function Return Value ..
Real (Kind=nag_wp) :: f
! .. Scalar Arguments ..
Integer, Intent (In) :: ndim
! .. Array Arguments ..
Real (Kind=nag_wp), Intent (In) :: x(ndim)
! .. Intrinsic Procedures ..
Intrinsic :: exp
! .. Executable Statements ..
f = (x(1)*x(2)*x(3))**6/(x(4)+2.0E0_nag_wp)**8* &
exp(-2.0E0_nag_wp*x(2)-0.5E0_nag_wp*x(3)*x(3))
Return
End Function f
End Module d01fbfe_mod
Program d01fbfe
! D01FBF Example Main Program
! .. Use Statements ..
Use d01fbfe_mod, Only: f, ndim, nout
Use nag_library, Only: d01fbf, d01tbf, nag_wp
! .. Implicit None Statement ..
Implicit None
! .. Local Scalars ..
Real (Kind=nag_wp) :: a, ans, b
Integer :: i, ifail, j, lwa
! .. Local Arrays ..
Real (Kind=nag_wp), Allocatable :: abscis(:), weight(:)
Integer :: nptvec(ndim)
! .. Intrinsic Procedures ..
Intrinsic :: sum
! .. Executable Statements ..
Write (nout,*) 'D01FBF Example Program Results'
nptvec(1:ndim) = (/4,4,4,4/)
lwa = sum(nptvec(1:ndim))
Allocate (abscis(lwa),weight(lwa))
j = 1
Do i = 1, 4
ifail = 0
Select Case (i)
Case (1)
a = 1.0E0_nag_wp
b = 2.0E0_nag_wp
Call d01tbf(0,a,b,nptvec(i),weight(j),abscis(j),ifail)
Case (2)
a = 0.0E0_nag_wp
b = 2.0E0_nag_wp
Call d01tbf(-3,a,b,nptvec(i),weight(j),abscis(j),ifail)
Case (3)
a = 0.0E0_nag_wp
b = 0.5E0_nag_wp
Call d01tbf(-4,a,b,nptvec(i),weight(j),abscis(j),ifail)
Case (4)
a = 1.0E0_nag_wp
b = 2.0E0_nag_wp
Call d01tbf(-5,a,b,nptvec(i),weight(j),abscis(j),ifail)
End Select
j = j + nptvec(i)
End Do
ifail = 0
ans = d01fbf(ndim,nptvec,lwa,weight,abscis,f,ifail)
Write (nout,*)
Write (nout,99999) 'Answer = ', ans
99999 Format (1X,A,F10.5)
End Program d01fbfe