! E01ZNF Example Program Text ! Mark 24 Release. NAG Copyright 2012. Module e01znfe_mod ! E01ZNF 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 :: one = 1.0_nag_wp Real (Kind=nag_wp), Parameter :: two = 2.0_nag_wp Integer, Parameter :: d = 6, nin = 5, nout = 6 Contains Function funct(x) ! This function evaluates the 6D function funct. ! .. Function Return Value .. Real (Kind=nag_wp) :: funct ! .. Array Arguments .. Real (Kind=nag_wp), Intent (In) :: x(d) ! .. Executable Statements .. funct = x(1)*x(2)*x(3)/(one+two*x(4)*x(5)*x(6)) Return End Function funct End Module e01znfe_mod Program e01znfe ! E01ZNF Example Main Program ! .. Use Statements .. Use nag_library, Only: e01zmf, e01znf, g05kff, g05saf, nag_wp Use e01znfe_mod, Only: d, funct, nin, nout ! .. Implicit None Statement .. Implicit None ! .. Parameters .. Integer, Parameter :: lseed = 1 ! .. Local Scalars .. Real (Kind=nag_wp) :: fun Integer :: genid, i, ifail, liq, lrq, & lstate, m, n, nq, nw, subid ! .. Local Arrays .. Real (Kind=nag_wp), Allocatable :: f(:), q(:), qx(:,:), rq(:), & x(:,:), xe(:,:) Integer, Allocatable :: iq(:), state(:) Integer :: seed(lseed) ! .. Intrinsic Procedures .. Intrinsic :: abs, real ! .. Executable Statements .. Write (nout,*) 'E01ZNF Example Program Results' ! Skip heading in data file Read (nin,*) ! Read in the base generator information and seeds Read (nin,*) genid, subid, seed(1) ! Initial call to initialiser to get size of STATE array lstate = 0 Allocate (state(lstate)) ifail = 0 Call g05kff(genid,subid,seed,lseed,state,lstate,ifail) ! Reallocate STATE Deallocate (state) Allocate (state(lstate)) ! Initialize the generator to a repeatable sequence ifail = 0 Call g05kff(genid,subid,seed,lseed,state,lstate,ifail) ! Input the number of nodes. Read (nin,*) m liq = 2*m + 1 lrq = (d+1)*(d+2)/2*m + 2*d + 1 Allocate (x(d,m),f(m),iq(liq),rq(lrq)) ! Generate the data points X ifail = 0 Call g05saf(d*m,state,x,ifail) ! Evaluate F Do i = 1, m f(i) = funct(x(1,i)) End Do ! Generate the interpolant using E01ZMF. nq = 0 nw = 0 ifail = 0 Call e01zmf(d,m,x,f,nw,nq,iq,rq,ifail) ! Input the number of evaluation points. Read (nin,*) n Allocate (xe(d,n),q(n),qx(d,n)) ! Generate a set of evaluation points lying on diagonal line ! xe(1:d,i) = xe(1,i) = i/(n+1). Do i = 1, n xe(1:d,i) = real(i,kind=nag_wp)/real(n+1,kind=nag_wp) End Do ! Evaluate the interpolant. ifail = 0 Call e01znf(d,m,x,f,iq,rq,n,xe,q,qx,ifail) Write (nout,99997) Write (nout,99998) Do i = 1, n fun = funct(xe(1,i)) Write (nout,99999) i, fun, q(i), abs(fun-q(i)) End Do 99999 Format (1X,I4,1X,3F10.4) 99998 Format (4X,'---|',20('-'),'+',15('-')) 99997 Format (/4X,'I |',2X,'F(I)',6X,'Q(I)',4X,'|',1X,'|F(I)-Q(I)|') End Program e01znfe