! C05RCF Example Program Text ! Mark 24 Release. NAG Copyright 2012. Module c05rcfe_mod ! C05RCF 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 :: factor = 100.0_nag_wp Integer, Parameter :: maxfev = 1000, mode = 2, n = 9, & nout = 6, nprint = 0 Contains Subroutine fcn(n,x,fvec,fjac,iuser,ruser,iflag) ! .. Parameters .. Real (Kind=nag_wp), Parameter :: & coeff(5) = (/-1.0_nag_wp,3.0_nag_wp,-2.0_nag_wp,-2.0_nag_wp,-1.0_nag_wp/) ! .. Scalar Arguments .. Integer, Intent (Inout) :: iflag Integer, Intent (In) :: n ! .. Array Arguments .. Real (Kind=nag_wp), Intent (Inout) :: fjac(n,n), fvec(n), ruser(*) Real (Kind=nag_wp), Intent (In) :: x(n) Integer, Intent (Inout) :: iuser(*) ! .. Local Scalars .. Integer :: k ! .. Executable Statements .. If (iflag==0) Then ! Insert print statements here when NPRINT is positive. Continue Else If (iflag/=2) Then fvec(1:n) = (coeff(2)+coeff(3)*x(1:n))*x(1:n) - coeff(5) fvec(2:n) = fvec(2:n) + coeff(1)*x(1:(n-1)) fvec(1:(n-1)) = fvec(1:(n-1)) + coeff(4)*x(2:n) Else fjac(1:n,1:n) = 0.0_nag_wp fjac(1,1) = coeff(2) + 2.0_nag_wp*coeff(3)*x(1) fjac(1,2) = coeff(4) Do k = 2, n - 1 fjac(k,k-1) = coeff(1) fjac(k,k) = coeff(2) + 2.0_nag_wp*coeff(3)*x(k) fjac(k,k+1) = coeff(4) End Do fjac(n,n-1) = coeff(1) fjac(n,n) = coeff(2) + 2.0_nag_wp*coeff(3)*x(n) End If Return End Subroutine fcn End Module c05rcfe_mod Program c05rcfe ! C05RCF Example Main Program ! .. Use Statements .. Use nag_library, Only: c05rcf, dnrm2, nag_wp, x02ajf Use c05rcfe_mod, Only: factor, fcn, maxfev, mode, n, nout, nprint ! .. Implicit None Statement .. Implicit None ! .. Local Scalars .. Real (Kind=nag_wp) :: fnorm, xtol Integer :: ifail, j, nfev, njev ! .. Local Arrays .. Real (Kind=nag_wp), Allocatable :: diag(:), fjac(:,:), fvec(:), & qtf(:), r(:), x(:) Real (Kind=nag_wp) :: ruser(1) Integer :: iuser(1) ! .. Intrinsic Procedures .. Intrinsic :: sqrt ! .. Executable Statements .. Write (nout,*) 'C05RCF Example Program Results' Allocate (diag(n),fjac(n,n),fvec(n),qtf(n),r(n*(n+1)/2),x(n)) ! The following starting values provide a rough solution. x(1:n) = -1.0_nag_wp xtol = sqrt(x02ajf()) diag(1:n) = 1.0_nag_wp ifail = -1 Call c05rcf(fcn,n,x,fvec,fjac,xtol,maxfev,mode,diag,factor,nprint,nfev, & njev,r,qtf,iuser,ruser,ifail) Select Case (ifail) Case (0) ! The NAG name equivalent of dnrm2 is f06ejf fnorm = dnrm2(n,fvec,1) Write (nout,*) Write (nout,99999) 'Final 2-norm of the residuals =', fnorm Write (nout,*) Write (nout,*) 'Final approximate solution' Write (nout,*) Write (nout,99998)(x(j),j=1,n) Case (2:5) Write (nout,*) Write (nout,*) 'Approximate solution:' Write (nout,*) Write (nout,99998)(x(j),j=1,n) End Select 99999 Format (1X,A,E12.4) 99998 Format (1X,3F12.4) End Program c05rcfe