public function testPackedArray2()
 {
     $data = [1.0, 2.0, 3.0, 4.0];
     $matrix = new Matrix(1, 4);
     $matrix->fromPackedArray($data, 0);
     $this->assertEquals(1.0, $matrix->get(0, 0));
     $this->assertEquals(2.0, $matrix->get(0, 1));
     $this->assertEquals(3.0, $matrix->get(0, 2));
 }