--- Matrix.rows(rows, copy = true)
    creates a matrix where `rows' indicates rows.
    If optional argument `copy' is false, use the array as
    internal structure of the metrix without copying.

    rowsǤȤ롣
    rowsϥͥȤ(=)Ǥ롣
    ޤץ copy (false)ʤСʣԤʤ

