! E01TLF Example Program Text ! Mark 23 Release. NAG Copyright 2011. MODULE e01tlfe_mod ! E01TLF 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 :: six = 6.0_nag_wp REAL (KIND=nag_wp), PARAMETER :: three = 3.0_nag_wp INTEGER, PARAMETER :: nin = 5, nout = 6 CONTAINS SUBROUTINE funct(m,x,f) ! This subroutine evaluates the 4D function funct. ! .. Implicit None Statement .. IMPLICIT NONE ! .. Scalar Arguments .. INTEGER, INTENT (IN) :: m ! .. Array Arguments .. REAL (KIND=nag_wp), INTENT (OUT) :: f(m) REAL (KIND=nag_wp), INTENT (IN) :: x(4,m) ! .. Local Scalars .. REAL (KIND=nag_wp) :: c1, c2, c3, c4 INTEGER :: i ! .. Intrinsic Functions .. INTRINSIC cos ! .. Executable Statements .. DO i = 1, m c1 = cos(six*x(1,i)) c2 = cos(six*x(2,i)) c3 = six + six*(three*x(3,i)-one)**2 c4 = 1.25_nag_wp + cos(5.4_nag_wp*x(4,i)) f(i) = c4*c1*c2/c3 END DO RETURN END SUBROUTINE funct END MODULE e01tlfe_mod PROGRAM e01tlfe ! E01TLF Example Main Program ! .. Use Statements .. USE nag_library, ONLY : e01tkf, e01tlf, g05kff, g05saf, nag_wp USE e01tlfe_mod, ONLY : funct, nin, nout ! .. Implicit None Statement .. IMPLICIT NONE ! .. Parameters .. INTEGER, PARAMETER :: lseed = 1 ! .. Local Scalars .. INTEGER :: genid, i, ifail, liq, lrq, & lstate, m, n, nq, nw, subid ! .. Local Arrays .. REAL (KIND=nag_wp), ALLOCATABLE :: f(:), fun(:), q(:), qx(:,:), & rq(:), x(:,:), xe(:,:) INTEGER, ALLOCATABLE :: iq(:), state(:) INTEGER :: seed(lseed), seed2(lseed) ! .. Intrinsic Functions .. INTRINSIC abs ! .. Executable Statements .. WRITE (nout,*) 'E01TLF Example Program Results' ! Skip heading in data file READ (nin,*) ! Read in the base generator information and seeds READ (nin,*) genid, subid, seed(1), seed2(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 = 15*m + 9 ALLOCATE (x(4,m),f(m),iq(liq),rq(lrq)) ! Generate the data points X ifail = 0 CALL g05saf(4*m,state,x,ifail) ! Evaluate F CALL funct(m,x,f) ! Generate the interpolant using E01TKF. nq = 0 nw = 0 ifail = 0 CALL e01tkf(m,x,f,nw,nq,iq,rq,ifail) ! Input the number of evaluation points. READ (nin,*) n ALLOCATE (xe(4,n),q(n),qx(4,n),fun(n)) ! Generate repeatable evaluation points. ifail = 0 CALL g05kff(genid,subid,seed2,lseed,state,lstate,ifail) ifail = 0 CALL g05saf(4*n,state,xe,ifail) ! Evaluate the interpolant. ifail = 0 CALL e01tlf(m,x,f,iq,rq,n,xe,q,qx,ifail) WRITE (nout,99997) WRITE (nout,99998) CALL funct(n,xe,fun) WRITE (nout,99999) (i,fun(i),q(i),abs(fun(i)-q(i)),i=1,n) 99999 FORMAT (1X,I4,1X,2F10.4,2X,F10.4) 99998 FORMAT (4X,'---+',20('-'),'+',11('-'),'+') 99997 FORMAT (/4X,'I |',2X,'F(I)',6X,'Q(I)',4X,'|',1X,'|F(I)-Q(I)|') END PROGRAM e01tlfe