! C05AZF Example Program Text ! Mark 23 Release. NAG Copyright 2011. MODULE c05azfe_mod ! C05AZF 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 :: tolx = 1.0E-5_nag_wp INTEGER, PARAMETER :: ir = 0, nout = 6 CONTAINS FUNCTION f(x) ! .. Implicit None Statement .. IMPLICIT NONE ! .. Function Return Value .. REAL (KIND=nag_wp) :: f ! .. Scalar Arguments .. REAL (KIND=nag_wp), INTENT (IN) :: x ! .. Intrinsic Functions .. INTRINSIC exp ! .. Executable Statements .. f = exp(-x) - x RETURN END FUNCTION f END MODULE c05azfe_mod PROGRAM c05azfe ! C05AZF Example Main Program ! .. Use Statements .. USE nag_library, ONLY : c05azf, nag_wp USE c05azfe_mod, ONLY : f, ir, nout, tolx ! .. Implicit None Statement .. IMPLICIT NONE ! .. Local Scalars .. REAL (KIND=nag_wp) :: fx, x, y INTEGER :: ifail, ind ! .. Local Arrays .. REAL (KIND=nag_wp) :: c(17) ! .. Executable Statements .. WRITE (nout,*) 'C05AZF Example Program Results' WRITE (nout,*) WRITE (nout,*) ' Iterations' WRITE (nout,*) ! Initial values, root in [0,1]. x = 0.0_nag_wp y = 1.0_nag_wp ind = 1 ifail = -1 ! Reverse communication loop REVCOM: DO CALL c05azf(x,y,fx,tolx,ir,c,ind,ifail) IF (ind==0) THEN EXIT REVCOM END IF fx = f(x) WRITE (nout,99999) ' X =', x, ' FX =', fx, ' IND =', ind END DO REVCOM ! Results SELECT CASE (ifail) CASE (0) WRITE (nout,*) WRITE (nout,*) ' Solution' WRITE (nout,*) WRITE (nout,99998) ' X =', x, ' Y =', y CASE (4,5) WRITE (nout,99998) 'X =', x, ' Y =', y END SELECT 99999 FORMAT (1X,A,F8.5,A,E12.4,A,I2) 99998 FORMAT (1X,2(A,F8.5)) END PROGRAM c05azfe