vendor/markbaker/matrix/classes/src/Functions/diagonal.php


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<?php

/**
 *
 * Function code for the matrix diagonal() function
 *
 * @copyright  Copyright (c) 2018 Mark Baker (https://github.com/MarkBaker/PHPMatrix)
 * @license    https://opensource.org/licenses/MIT    MIT
 */

namespace Matrix;

/**
 * Returns the diagonal of a matrix or an array.
 *
 * @param Matrix|array $matrix Matrix or an array to treat as a matrix.
 * @return Matrix The new matrix
 * @throws Exception If argument isn't a valid matrix or array.
 */
if (!function_exists(__NAMESPACE__ . '\\diagonal')) {
    function diagonal($matrix): Matrix
    {
        if (is_array($matrix)) {
            $matrix = new Matrix($matrix);
        }
        if (!$matrix instanceof Matrix) {
            throw new Exception('Must be Matrix or array');
        }

        return Functions::diagonal($matrix);
    }
}