subroutine deoftotvar( data, nx, nt, totvar, doswitched,icovcor, covariance, correlation )

!c	-------------------------------------------------
!c	Returns the total variance in the field so we can
!c	normalize by it.
!c
!c	Inputs:
!c
!c		data(nx,nt): data to calculate upon
!c
!c		nx, nt:	size of 'data'.
!c
!c		doswitched: if .TRUE., then we are working
!c			in switched (nx,nt) space, false 
!c			otherwise.
!c
!c		icovcor: if (icovcor .eq. covariance), then
!c			we are using the covariance array;
!c			if( icovcor .eq. correlation) then
!c			we are using the correlation array.
!c
!c	Outputs:
!c
!c		totvar: estimate of total variance
!c
!c	-------------------------------------------------

      implicit none

      integer :: nx, nt, icovcor, covariance, correlation
      double precision :: data(nx,nt), totvar, sum, fact
      logical :: doswitched
      integer :: i, j

      if( icovcor .eq. correlation ) then
         if( doswitched ) then
            totvar = float( nt )
         else
            totvar = float( nx )
         endif
         return
      endif

      totvar = 0.0
      if( doswitched ) then
         fact = 1.0/float(nx-1)
      else
         fact = 1.0/float(nt-1)
      endif
      do j=1, nt
         sum = 0.0
         do i=1, nx
            sum = sum + data(i,j)*data(i,j)
         enddo
         totvar = totvar + sum*fact
      enddo

      return
      end