!-------------------------------------- LICENCE BEGIN ------------------------------------
!Environment Canada - Atmospheric Science and Technology License/Disclaimer,
!                     version 3; Last Modified: May 7, 2008.
!This is free but copyrighted software; you can use/redistribute/modify it under the terms
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!

      subroutine calcsv 1,6
      use mod4dv, only : l4dvar
#if defined (DOC)
*
***s/r minimize  - Compute Singluar Vectors
*
*Author  : M. Buehner *ARMA/MSC July, 2002
*Revision:
*
*Arguments
*    -NONE-
#endif
      IMPLICIT NONE
*implicits
#include "comlun.cdk"
#include "comdim.cdk"
#include "comcva.cdk"
#include "comsv.cdk"
#include "comanl.cdk"
*
      LOGICAL LTEMP
C
      INTEGER IERR,ILEN
c
      call printrev("SUBROUTINE calcsv:",17)
c
c Calculate or Read in Hessian Eigenvectors and proceed
c
      WRITE(NULOUT,*) 'IN CALCSV: NPRECON=',nprecon
      IF(NPRECON.ge.1) THEN
        NCV=2*NPRECON
        NCORDIM=NVADIM
        ILEN = NCORDIM*NCV
        CALL HPALLOC(PTRRNK1,MAX(ILEN,1),IERR,8)
        ILEN = NCORDIM*NPRECON
        CALL HPALLOC(PTRRNK2,MAX(ILEN,1),IERR,8)
        ILEN = NPRECON
        CALL HPALLOC(PTHESEVAL,MAX(ILEN,1),IERR,8)
        WRITE(NULOUT,*) '**************************************'
        WRITE(NULOUT,*) '***SETTING UP HESSIAN EIGEN VECTORS***'
        WRITE(NULOUT,*) '**************************************'
c calculate 3Dvar Hessian (not 4Dvar)
        LTEMP=L4DVAR
        L4DVAR=.false.
        CALL SUPRECON
        L4DVAR=LTEMP
        nsim3d=0
      ENDIF
c
c Calculate Singular Vectors and quit (NAMELIST read in sudim)
c
      WRITE(NULOUT,*) 'IN MINIMIZE, NSV=',nsv,csvnorm
      call vflush(nulout)
      IF(NSV.ge.1) THEN
        IF(CSVNORM.eq.'E') THEN
          NSVDIM=NKGDIM*NI*NJ
        ELSE
          NSVDIM=NVADIM
        ENDIF
        NSVCV=3*NSV
        ILEN = NSVDIM*NSVCV
        CALL HPALLOC(PTSV,MAX(ILEN,1),IERR,8)
        ILEN = NSV
        CALL HPALLOC(PTSVEVAL,MAX(ILEN,1),IERR,8)
        write(nulout,*) 'nsvdim,nsvcv=',nsvdim,nsvcv
        WRITE(NULOUT,*) '**********************************'
        WRITE(NULOUT,*) '***CALCULATING SINGULAR VECTORS***'
        WRITE(NULOUT,*) '**********************************'
        CALL SUSV
      ENDIF
c
      if(l4dvar) call endsim
c
      RETURN
      END