def r_y(theta, r = Const::R_UNIT)
      r_a = Array.new

      begin
        s, c = Math.sin(theta), Math.cos(theta)
        a00 = c * r[0][0] - s * r[2][0]
        a01 = c * r[0][1] - s * r[2][1]
        a02 = c * r[0][2] - s * r[2][2]
        a20 = s * r[0][0] + c * r[2][0]
        a21 = s * r[0][1] + c * r[2][1]
        a22 = s * r[0][2] + c * r[2][2]
        r_a << [a00, a01, a02]
        r_a << r[1]
        r_a << [a20, a21, a22]
        return r_a
      rescue => e
        raise
      end
    end
def r_y(theta, r = Const::R_UNIT)
      r_a = Array.new

      begin
        s, c = Math.sin(theta), Math.cos(theta)
        a00 = c * r[0][0] - s * r[2][0]
        a01 = c * r[0][1] - s * r[2][1]
        a02 = c * r[0][2] - s * r[2][2]
        a20 = s * r[0][0] + c * r[2][0]
        a21 = s * r[0][1] + c * r[2][1]
        a22 = s * r[0][2] + c * r[2][2]
        r_a << [a00, a01, a02]
        r_a << r[1]
        r_a << [a20, a21, a22]
        return r_a
      rescue => e
        raise
      end
    end
=========================================================================
 回転行列（y 軸中心）

 @param:  theta  (回転量(rad))
 @param:  r      (回転行列)
 @return: r_a    (回転後)
=========================================================================