read Subroutine

    subroutine read (self, region)
        class(pif_h5part_type), intent(inout) :: self
        type(particle_type), intent(inout), target :: region
        real(rk), allocatable :: z(:, :)
        integer(8) :: istat, fid
        integer :: i

        self%numbers => pnl_obj%numbers
        self%float_objects => pnl_obj%float_objects
        self%ptc => region  ! 重定向粒子集
        self%ptc%hsml = pnl_obj%hsml
        self%nreal = self%numbers(1) + self%numbers(2)

        fid = h5pt_openr(cli_obj%working_directory.join.ioc_obj%input_file)
        if (fid == 0_8) then
            call terminal_obj%error('open pif h5part file failed')
        end if

        allocate (self%ptc%loc(2, self%numbers(4)), &
                  self%ptc%vel(2, self%numbers(4)), &
                  self%ptc%acc(2, self%numbers(4)), &
                  self%ptc%rho(self%numbers(4)), &
                  self%ptc%p(self%numbers(4)), &
                  self%ptc%mass(self%numbers(4)), &
                  self%ptc%u(self%numbers(4)), &
                  self%ptc%drho(self%numbers(4)), &
                  self%ptc%du(self%numbers(4)), &
                  self%ptc%c(self%numbers(4)), &
                  source=0.0_rk)
        allocate (self%ptc%itype(self%numbers(4)), source=0)

        allocate (z(self%numbers(4), 2), source=0.0_rk)
        ! if (cfg_obj%is_go_on) then
        !     istat = h5pt_setstep(fid, int(cfg_obj%go_on_step, 8))
        ! else
        istat = h5pt_setstep(fid, 1_8)
        ! end if

        istat = h5pt_readdata(fid, "X", z(:, 1))
        istat = h5pt_readdata(fid, "Y", z(:, 2))
        do i = 1, self%numbers(4)
            self%ptc%loc(:, i) = z(i, :)
        end do

        istat = h5pt_readdata(fid, "Vx", z(:, 1))
        istat = h5pt_readdata(fid, "Vy", z(:, 2))
        do i = 1, self%numbers(4)
            self%ptc%vel(:, i) = z(i, :)
        end do

        self%ptc%acc = 0.0_rk
        istat = h5pt_readdata(fid, "Mass", self%ptc%mass)
        istat = h5pt_readdata(fid, "Rho", self%ptc%rho)
        istat = h5pt_readdata(fid, "P", self%ptc%p)
        istat = h5pt_readdata(fid, "U", self%ptc%u)
        istat = h5pt_readdata(fid, "Itype", self%ptc%itype)

        istat = h5pt_close(fid)

    end subroutine read