/** * Calculate the length of a vector. * * @param * input * The matrix to calculate the length of. * * @return Vector length. */ function vectorLength(Matrix $input) { if (!$input->isVector()) { throw new MatrixError("Can only take the vector length of a vector."); } $v = $input->toPackedArray(); $rtn = 0.0; foreach ($v as $element) { $rtn += pow($element, 2); } return sqrt($rtn); }