! F90 Version.  NCCS = 12
SUBROUTINE echo_f90(N, niters, check)
  INTEGER, INTENT( IN ) :: N, niters
  REAL, INTENT( OUT ) :: check

  REAL, DIMENSION (N,N) :: P1, P2, P3, c
  INTEGER iter

  CALL echo_f90_setupInitialConditions(N, niters, check)

  DO iter=1, niters
    P3(2:N-1,2:N-1) = (2-4*c(2:N-1,2:N-1)) * P2(2:N-1,2:N-1) &
        + c(2:N-1,2:N-1)*(P2(1:N-2,2:N-1) + P2(3:N,2:N-1)    &
        + P2(2:N-1,1:N-2) + P2(2:N-1,3:N)) - P1(2:N-1,2:N-1)
    P1 = P2
    P2 = P3
  END DO

  check = P1(N/2,N/2)

  RETURN
END