counter_child_id Function

public pure function counter_child_id(parent_id, ordinal) result(child_id)

親の乱数 id と子の番号から、衝突しにくい 63 bit の子 id を作る（二次電子などの派生粒子用）。

Arguments

Type IntentOptional Attributes Name
integer(kind=i64), intent(in) :: parent_id
integer(kind=i64), intent(in) :: ordinal

Return Value integer(kind=i64)


Source Code

  pure integer(i64) function counter_child_id(parent_id, ordinal) result(child_id)
    integer(i64), intent(in) :: parent_id, ordinal
    integer(i64) :: hi, lo

    hi = murmur3_tuple(lane_seed(1), parent_id, [ordinal, 4099_i64])
    lo = murmur3_tuple(lane_seed(2), parent_id, [ordinal, 4099_i64])
    child_id = iand(ior(ishft(hi, 32), lo), huge(0_i64))
  end function counter_child_id