matrix::colAsVector function incorrectly using $this->row as multiplier

[sneakyimp]

The colAsVector method clearly has a problem. Some simple code to illustrate:

require __DIR__ . '/vendor/autoload.php';
use Np\matrix;
$v = matrix::ar([
	[1,2,3,4,5,6],
	[7,8,9,10,11,12]
]);
echo $v, "\n";
$shape = $v->getShape();
for($i=0; $i<$shape->n; $i++) {
	$vect = $v->colAsVector($i);
	echo $vect, "\n";
}

The output is clearly wrong, and shows the second item in each column drifting off from the correct value.

Np\matrix
1.000000  2.000000  3.000000  4.000000  5.000000  6.000000  
7.000000  8.000000  9.000000  10.000000  11.000000  12.000000  

Np\vector
1.000000  3.000000  

Np\vector
2.000000  4.000000  

Np\vector
3.000000  5.000000  

Np\vector
4.000000  6.000000  

Np\vector
5.000000  7.000000  

Np\vector
6.000000  8.000000  

I believe this modified version of the function may remedy the problem:

    /**
     * Return a col as vector from the matrix.
     * @param int $index
     * @return \Np\vector
     */
    public function colAsVector(int $index): vector {
        $vr = vector::factory($this->row);
        for ($i = 0; $i < $this->row; $i++) {
            $vr->data[$i] = $this->data[($i *  $this->col) + $index];
        }
        return $vr;
    }

[ghostjat]

@sneakyimp
thanks for bring the issue,library is not fully tested. kindly join the project as i have very less time to maintain it.you can make pull request with your name tag.
i will update this issue in this winter breaks.