uniform_gradient_is_equal Function

  logical function uniform_gradient_is_equal(this,rhs) result(iseq)
    !* Author: Chris MacMackin
    !  Date: July 2017
    !
    ! Evaluates whether two scalar fields are equal within a tolerance,
    ! specified by `set_tol`.
    !
    class(uniform_gradient_field), intent(in) :: this
    class(scalar_field), intent(in) :: rhs
    real(r8) :: normalization
    integer :: i
    call this%guard_temp(); call rhs%guard_temp()
    iseq = .true.
    select type(rhs)
    class is(uniform_gradient_field)
      iseq = (this%uniform_scalar_field == rhs%uniform_scalar_field)
      do i = 1, size(this%grad)
        if (.not. iseq) return
        normalization = abs(this%grad(i))
        if (normalization < get_tol()) normalization = 1.0_r8
        iseq = iseq .and.( ((this%grad(i)-rhs%grad(i))/normalization < &
                             get_tol()) .or. (is_nan(this%grad(i)).and. &
                                              is_nan(rhs%grad(i))) )
      end do
    class default
      iseq = (rhs == this)
    end select
    call this%clean_temp(); call rhs%clean_temp()
  end function uniform_gradient_is_equal