! C06LBF Example Program Text
! Mark 30.1 Release. NAG Copyright 2024.
Module c06lbfe_mod
! C06LBF 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 :: nin = 5, nout = 6
Contains
Function f(s)
! .. Function Return Value ..
Complex (Kind=nag_wp) :: f
! .. Scalar Arguments ..
Complex (Kind=nag_wp), Intent (In) :: s
! .. Intrinsic Procedures ..
Intrinsic :: cmplx
! .. Executable Statements ..
f = cmplx(3.0E0_nag_wp,kind=nag_wp)/(s**2-cmplx(9.0E0_nag_wp,kind= &
nag_wp))
Return
End Function f
End Module c06lbfe_mod
Program c06lbfe
! C06LBF Example Main Program
! .. Use Statements ..
Use c06lbfe_mod, Only: f, nin, nout
Use nag_library, Only: c06lbf, c06lcf, nag_wp
! .. Implicit None Statement ..
Implicit None
! .. Local Scalars ..
Real (Kind=nag_wp) :: b, epstol, exact, finv, pserr, &
sigma, sigma0, t
Integer :: ifail, j, m, mmax
! .. Local Arrays ..
Real (Kind=nag_wp), Allocatable :: acoef(:)
Real (Kind=nag_wp) :: errvec(8)
! .. Intrinsic Procedures ..
Intrinsic :: abs, exp, real, sinh
! .. Executable Statements ..
Write (nout,*) 'C06LBF Example Program Results'
! Skip heading in data file
Read (nin,*)
Read (nin,*) mmax
Allocate (acoef(mmax))
Read (nin,*) sigma0, epstol, sigma, b
! ifail: behaviour on error exit
! =0 for hard exit, =1 for quiet-soft, =-1 for noisy-soft
ifail = 0
! Compute inverse transform
Call c06lbf(f,sigma0,sigma,b,epstol,mmax,m,acoef,errvec,ifail)
Write (nout,*)
Write (nout,99999) 'No. of coefficients returned by C06LBF =', m
Write (nout,*)
Write (nout,99998) ' ', 'Computed', 'Exact', 'Pseudo'
Write (nout,99998) 't', ' f(t)', ' f(t)', ' error'
Write (nout,*)
! Evaluate inverse transform for different values of t
Do j = 0, 5
t = real(j,kind=nag_wp)
Call c06lcf(t,sigma,b,m,acoef,errvec,finv,ifail)
exact = sinh(3.0E0_nag_wp*t)
pserr = abs(finv-exact)/exp(sigma*t)
Write (nout,99997) t, finv, exact, pserr
End Do
99999 Format (1X,A,I6)
99998 Format (1X,A10,A15,A15,A12)
99997 Format (1X,1P,E10.2,2E15.4,E12.1)
End Program c06lbfe