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subroutine da_kmat_mul(grid, config_flags, & 1,6
it, cv_size, xbx, be, iv, &
xhat, qhat, cv, &
re, y, j_cost, eignvec, eignval, neign)
!-------------------------------------------------------------------------
! Purpose: Multiply the innovation vector by the Kalman Gain Matrix K
! using the precomputed Lanczos eigenpairs
!
! Called from da_solve
!
! History: 05/04/2011 Creation (Tom Auligne)
! 09/06/2012 Modified to allow variable ntmax size for each outerloop (Mike Kavulich)
!
!-------------------------------------------------------------------------
implicit none
type(domain), intent(inout) :: grid
type(grid_config_rec_type), intent(inout) :: config_flags
integer, intent(in) :: it ! external iteration.
integer, intent(in) :: cv_size ! Total cv size
type (xbx_type),intent(inout) :: xbx ! Header & non-gridded vars.
type (be_type), intent(in) :: be ! background error structure.
type (iv_type), intent(inout) :: iv ! ob. increment vector.
real, intent(out) :: xhat(1:cv_size) ! Output vector: xhat=K.d
real, intent(in) :: qhat(1:cv_size, 0:ntmax(it)) ! Ritz vectors
real, intent(in) :: cv(1:cv_size) ! control variable (local).
type (y_type), intent(inout) :: re ! residual (o-a) structure.
type (y_type), intent(inout) :: y ! y = H(x_inc) structure.
type (j_type), intent(out) :: j_cost ! cost function
real*8, intent(in) :: eignvec(ntmax(it), ntmax(it))
real*8, intent(in) :: eignval(ntmax(it))
integer, intent(in) :: neign
real :: shat(1:cv_size) ! cv copy.
if (trace_use) call da_trace_entry
("da_kmat_mul")
write(*,*) 'Computing Analysis Increment: v = K.d = A.H^T.R-1.[y^o-H(x_b)]'
! Transfer [y^o-H(x_b)] information from iv(iv_type) into re(y_type)
call da_zero_y(iv,y)
call da_calculate_residual(iv,y,re)
! H^T.R^-1.[y^o-H(x_b)]
call da_calculate_gradj(1,1,cv_size,0,0,0,0,xbx,be,iv,cv,y,shat,grid,config_flags,re)
shat = - shat !! Compensate for sign in calculation of grad_v (Jo)
! A.H^T.R^-1.[y^o-H(x_b)]
call da_amat_mul(be, grid, cv_size, ntmax(it), neign, 1.0/eignval, eignvec, qhat, shat, xhat)
if (trace_use) call da_trace_exit ("da_kmat_mul")
end subroutine da_kmat_mul