imex_initialize Subroutine

  subroutine imex_initialize(this, lev)
    class(pf_imex_t),  intent(inout) :: this
    class(pf_level_t), intent(inout) :: lev

    real(pfdp) :: dsdc(lev%nnodes-1)
    integer    :: m, nnodes

    this%npieces = 2

    nnodes = lev%nnodes
    allocate(this%SdiffE(nnodes-1,nnodes))  !  S-FE
    allocate(this%SdiffI(nnodes-1,nnodes))  !  S-BE

    this%SdiffE = lev%s0mat
    this%SdiffI = lev%s0mat

    dsdc = lev%nodes(2:nnodes) - lev%nodes(1:nnodes-1)
    do m = 1, nnodes-1
       this%SdiffE(m,m)   = this%SdiffE(m,m)   - dsdc(m)
       this%SdiffI(m,m+1) = this%SdiffI(m,m+1) - dsdc(m)
    end do
  end subroutine imex_initialize