C
      SUBROUTINE OPTIM(FUNC,XVLO,XVEC,XVHI,NVEC,IOPT)
C
C Subroutine OPTIM: Master optimization test routine. Uses a number
C                   of methods to look for minima of function FUNC
C                   as the NVEC parameters in XVEC are varied between 
C                   their limits of XVLO and XVHI.
C
C Update history:
C    V1.0    Original version                            8-Oct-1992
C
      IMPLICIT NONE
C
C Arguments:
C    FUNC = R*4 function = function to optimize
C    XVLO = R*4(1)       = array of lower limits to XVEC
C    XVEC = R*4(1)       = array of quantities to find at minimum
C    XVHI = R*4(1)       = array of upper limits to XVEC
C    NVLN = I*4          = physical length of vectors
C    NVEC = I*4          = number of parameters
C    IOPT = I*4          = minimization type
C
      REAL*4    FUNC
      EXTERNAL  FUNC
      REAL*4    XVLO(1),XVEC(1),XVHI(1)
      INTEGER*4 IOPT,NVEC
C
C Subprogrammes
C    GRIDS = subroutine = perform grid search
C    MONTE = subroutine = perform Monte-Carlo search
C    POWLL = subroutine = perform Powell minimization
C    SMPLX = subroutine = perform simplex minimization
C    SIMAN = subroutine = perform simulated annealing
C    SIMMU = subroutine = perform simulated annealing, multiple-moves
C    SIMPO = subroutine = perform SA + Powell
C    SIMPU = subroutine = perform SA(multiple) + Powell
C
      EXTERNAL GRIDS,MONTE,POWLL
C
C Branch according to option
C
      IF     (IOPT .EQ. 1) THEN
        CALL GRIDS(FUNC,XVLO,XVEC,XVHI,NVEC)
      ELSEIF (IOPT .EQ. 2) THEN
        CALL MONTE(FUNC,XVLO,XVEC,XVHI,NVEC)
      ELSEIF (IOPT .EQ. 3) THEN
        CALL POWLL(FUNC,XVLO,XVEC,XVHI,NVEC)
      ELSEIF (IOPT .EQ. 4) THEN
        CALL SMPLX(FUNC,XVLO,XVEC,XVHI,NVEC)
      ELSEIF (IOPT .EQ. 5) THEN
        CALL SIMAN(FUNC,XVLO,XVEC,XVHI,NVEC)
      ELSEIF (IOPT .EQ. 6) THEN
        CALL SIMMU(FUNC,XVLO,XVEC,XVHI,NVEC)
      ELSEIF (IOPT .EQ. 7) THEN
        CALL SIMPO(FUNC,XVLO,XVEC,XVHI,NVEC)
      ELSEIF (IOPT .EQ. 8) THEN
        CALL SIMPU(FUNC,XVLO,XVEC,XVHI,NVEC)
      ELSE
        WRITE (6,699)
      ENDIF
C
C End
C
      RETURN
C
 699  FORMAT (' '/
     +        ' *** Error: illegal option in OPTIM ***'/)
C
      END