tridia.f90

CLM集合卡曼滤波数据同化算法

      subroutine tridia (n, a, b, c, r, u)
      
      implicit none
      integer, intent(in) :: n
      real, intent(in) :: a(1:n),b(1:n),c(1:n),r(1:n)
      real, intent(out) :: u(1:n)

      integer j
      real gam(1:n),bet
! -----------------------------------------------------------------

      bet = b(1)
      u(1) = r(1) / bet
      do j = 2, n
            gam(j) = c(j-1) / bet
            bet = b(j) - a(j) * gam(j)
            u(j) = (r(j) - a(j)*u(j-1)) / bet
      end do
      do j = n-1, 1, -1
            u(j) = u(j) - gam(j+1) * u(j+1)
      end do

      end subroutine tridia