! D01GBF Example Program Text
! Mark 30.3 Release. nAG Copyright 2024.
Module d01gbfe_mod
! D01GBF 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 :: lenwrk = 500, maxcls = 20000, &
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 = 4.0E0_nag_wp*x(1)*x(3)**2*exp(2.0E0_nag_wp*x(1)*x(3))/ &
(1.0E0_nag_wp+x(2)+x(4))**2
Return
End Function f
End Module d01gbfe_mod
Program d01gbfe
! D01GBF Example Main Program
! .. Use Statements ..
Use d01gbfe_mod, Only: f, lenwrk, maxcls, ndim, nout
Use nag_library, Only: d01gbf, nag_wp
! .. Implicit None Statement ..
Implicit None
! .. Local Scalars ..
Real (Kind=nag_wp) :: acc, eps, finest
Integer :: ifail, mincls
! .. Local Arrays ..
Real (Kind=nag_wp), Allocatable :: a(:), b(:), wrkstr(:)
! .. Executable Statements ..
Write (nout,*) 'D01GBF Example Program Results'
Allocate (a(ndim),b(ndim),wrkstr(lenwrk))
a(1:ndim) = 0.0E0_nag_wp
b(1:ndim) = 1.0E0_nag_wp
eps = 0.01E0_nag_wp
mincls = 1000
ifail = -1
Call d01gbf(ndim,a,b,mincls,maxcls,f,eps,acc,lenwrk,wrkstr,finest,ifail)
Select Case (ifail)
Case (0,2)
Write (nout,*)
Write (nout,99998) 'Requested accuracy = ', eps
Write (nout,99997) 'Estimated value = ', finest
Write (nout,99998) 'Estimated accuracy = ', acc
Write (nout,99999) 'Number of evaluations = ', mincls
End Select
99999 Format (1X,A,I5)
99998 Format (1X,A,E13.2)
99997 Format (1X,A,F13.5)
End Program d01gbfe