! D02PFF Example Program Text ! Mark 24 Release. NAG Copyright 2012. Module d02pffe_mod ! D02PFF Example Program Module: ! Parameters and User-defined Routines ! .. Use Statements .. Use nag_library, Only: nag_wp ! .. Implicit None Statement .. Implicit None ! .. Parameters .. Real (Kind=nag_wp), Parameter :: tol1 = 1.0E-4_nag_wp Real (Kind=nag_wp), Parameter :: tol2 = 1.0E-5_nag_wp Integer, Parameter :: liwsav = 130, n = 2, nin = 5, & nout = 6 Integer, Parameter :: lrwsav = 350 + 32*n Contains Subroutine f(t,n,y,yp,iuser,ruser) ! .. Scalar Arguments .. Real (Kind=nag_wp), Intent (In) :: t Integer, Intent (In) :: n ! .. Array Arguments .. Real (Kind=nag_wp), Intent (Inout) :: ruser(*) Real (Kind=nag_wp), Intent (In) :: y(n) Real (Kind=nag_wp), Intent (Out) :: yp(n) Integer, Intent (Inout) :: iuser(*) ! .. Executable Statements .. yp(1) = y(2) yp(2) = -y(1) Return End Subroutine f End Module d02pffe_mod Program d02pffe ! D02PFF Example Main Program ! .. Use Statements .. Use nag_library, Only: d02pff, d02pqf, d02ptf, nag_wp Use d02pffe_mod, Only: f, liwsav, lrwsav, n, nin, nout, tol1, tol2 ! .. Implicit None Statement .. Implicit None ! .. Local Scalars .. Real (Kind=nag_wp) :: hnext, hstart, tend, tnow, tol, & tstart, waste Integer :: i, ifail, method, stpcst, & stpsok, totf ! .. Local Arrays .. Real (Kind=nag_wp) :: ruser(1) Real (Kind=nag_wp), Allocatable :: rwsav(:), thres(:), ynow(:), & ypnow(:), ystart(:) Integer :: iuser(1) Integer, Allocatable :: iwsav(:) ! .. Executable Statements .. Write (nout,*) 'D02PFF Example Program Results' ! Skip heading in data file Read (nin,*) Read (nin,*) method Allocate (thres(n),iwsav(liwsav),rwsav(lrwsav),ynow(n),ypnow(n), & ystart(n)) ! Set initial conditions and input for D02PQF Read (nin,*) tstart, tend Read (nin,*) ystart(1:n) Read (nin,*) hstart Read (nin,*) thres(1:n) Do i = 1, 2 If (i==1) tol = tol1 If (i==2) tol = tol2 ! ifail: behaviour on error exit ! =0 for hard exit, =1 for quiet-soft, =-1 for noisy-soft ifail = 0 Call d02pqf(n,tstart,tend,ystart,tol,thres,method,hstart,iwsav,rwsav, & ifail) Write (nout,99999) tol Write (nout,99998) Write (nout,99997) tstart, ystart(1:n) loop: Do ifail = 0 Call d02pff(f,n,tnow,ynow,ypnow,iuser,ruser,iwsav,rwsav,ifail) If (ifail==0) Then Write (nout,99997) tnow, ynow(1:n) If (tnow>=tend) Exit loop Else Exit loop End If End Do loop ifail = 0 Call d02ptf(totf,stpcst,waste,stpsok,hnext,iwsav,rwsav,ifail) Write (nout,99996) totf End Do 99999 Format (/' Calculation with TOL = ',E8.1) 99998 Format (/' t y1 y2'/) 99997 Format (1X,F6.3,2(3X,F8.4)) 99996 Format (/' Cost of the integration in evaluations of F is',I6) End Program d02pffe