src/Maths/Algebra/Matrix.php
public function validY()
    {
        return (bool) ($this->validX() && !is_null($this->keyY()) && isset($this->data[$this->keyX(true)][$this->keyY(true)]));
    }
public function validY()
    {
        return (bool) ($this->validX() && !is_null($this->keyY()) && isset($this->data[$this->keyX(true)][$this->keyY(true)]));
    }
Test if current `y` column is valid

@return  bool