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subroutine da_amat_mul(be, grid, cv_size, ntmaxit, neign, eignval, eignvec, qhat, shat, xhat) 1,3
!-------------------------------------------------------------------------
! Purpose: Multiply a control vector by the Analysis Error Cov Matrix A
!
! Called from da_solve
!
! History: 08/16/2010 Creation (Tom Auligne)
!
!-------------------------------------------------------------------------
implicit none
type (be_type), intent(in) :: be ! Background error structure.
type (domain), intent(in) :: grid
integer, intent(in) :: cv_size
integer, intent(in) :: ntmaxit
integer, intent(in) :: neign
real*8, intent(in) :: eignvec(ntmaxit, ntmaxit)
real*8, intent(in) :: eignval(ntmaxit)
real, intent(in) :: qhat(cv_size, 0:ntmaxit) ! Ritz vectors
real, intent(in) :: shat(cv_size) ! Input vector to multiply by A
real, intent(out):: xhat(cv_size) ! Output vector: xhat = A.shat
#ifdef CLOUD_CV
integer :: mz(13) ! mz for each variable
#else
integer :: mz(7)
#endif
integer :: jp_start, jp_end ! Start/end indices of Jp.
integer :: i, j
real :: dot_cv
if (trace_use) call da_trace_entry
("da_amat_mul")
#ifdef CLOUD_CV
mz = (/ be%v1%mz, be%v2%mz, be%v3%mz, be%v4%mz, be%v5%mz, be%v6%mz, be%v7%mz, be%v8%mz, be%v9%mz, be%v10%mz, be%v11%mz, be%alpha%mz, be % ne /)
#else
mz = (/ be%v1%mz, be%v2%mz, be%v3%mz, be%v4%mz, be%v5%mz, be%alpha%mz, be % ne /)
#endif
jp_start = be % cv % size_jb + be % cv % size_je + 1
jp_end = be % cv % size_jb + be % cv % size_je + be % cv % size_jp
xhat = 0.0
do j = 1, neign
dot_cv = da_dot_cv(cv_size, qhat(:,j), shat, grid, mz, jp_start, jp_end)
do i = 1, neign
xhat = xhat + qhat(:,i) * &
SUM(eignvec(i,1:neign)*eignval(1:neign)*eignvec(j,1:neign)) * dot_cv
end do
end do
if (trace_use) call da_trace_exit ("da_amat_mul")
end subroutine da_amat_mul