! C05AWF Example Program Text ! Mark 24 Release. NAG Copyright 2012. Module c05awfe_mod ! C05AWF Example Program Module: ! Parameters and User-defined Routines ! .. Use Statements .. Use nag_library, Only: nag_wp ! .. Implicit None Statement .. Implicit None ! .. Parameters .. Integer, Parameter :: nout = 6 Contains Function f(x,iuser,ruser) ! .. Function Return Value .. Real (Kind=nag_wp) :: f ! .. Scalar Arguments .. Real (Kind=nag_wp), Intent (In) :: x ! .. Array Arguments .. Real (Kind=nag_wp), Intent (Inout) :: ruser(*) Integer, Intent (Inout) :: iuser(*) ! .. Intrinsic Procedures .. Intrinsic :: exp ! .. Executable Statements .. f = exp(-x) - x Return End Function f End Module c05awfe_mod Program c05awfe ! C05AWF Example Main Program ! .. Use Statements .. Use nag_library, Only: c05awf, nag_wp Use c05awfe_mod, Only: f, nout ! .. Implicit None Statement .. Implicit None ! .. Local Scalars .. Real (Kind=nag_wp) :: eps, eta, x Integer :: ifail, k, nfmax ! .. Local Arrays .. Real (Kind=nag_wp) :: ruser(1) Integer :: iuser(1) ! .. Executable Statements .. Write (nout,*) 'C05AWF Example Program Results' Write (nout,*) ! Repeat with tolerance eps set to varying powers of 10: loop: Do k = 3, 4 eps = 10.0E0_nag_wp**(-k) x = 1.0E0_nag_wp eta = 0.0E0_nag_wp nfmax = 200 ifail = -1 Call c05awf(x,eps,eta,f,nfmax,iuser,ruser,ifail) Select Case (ifail) Case (0) Write (nout,99999) 'With EPS = ', eps, ' root = ', x Case (:-1) Exit loop Case (3,4) Write (nout,99999) 'With EPS = ', eps, ' final value = ', x End Select End Do loop 99999 Format (1X,A,E10.2,A,F14.5) End Program c05awfe