Creating lot of fields in a Symphony section

fields.php

<?php

// BOOTSTRAP SYMPHONY
define('DOCROOT', str_replace('/manifest', '', rtrim(dirname(__FILE__), '\\/') ));
define('VERBOSE', 1);
// section id
define('SOURCE', 41);

require_once(DOCROOT . '/symphony/lib/boot/bundle.php');
require_once(DOCROOT . '/symphony/lib/core/class.cacheable.php');
require_once(DOCROOT . '/symphony/lib/core/class.symphony.php');
require_once(DOCROOT . '/symphony/lib/core/class.administration.php');
require_once(DOCROOT . '/symphony/lib/toolkit/class.general.php');
require_once(TOOLKIT . '/class.sectionmanager.php');
require_once(TOOLKIT . '/class.entrymanager.php');

// creates the DB
Administration::instance();

$fieldTypes = array('input','checkbox');

for ($x = 1; $x <= 100; $x++) {
    $field = FieldManager::create($fieldTypes[array_rand($fieldTypes)]);
    $field->set('label', "Field $x");
    $field->set('element_name', "field-$x");
    $field->set('location', "main");
    $field->set('sortorder', (string)($x - 1));
    $field->set('parent_section', SOURCE);

    if (!$field->commit()) {
        echo "Error while commiting field $x" . PHP_EOL;
    } else if (VERBOSE) {
        $id = $field->get('id');
        echo "Field $x:$id created" . PHP_EOL;
    }
}

if (VERBOSE) {
    echo PHP_EOL . "All done." . PHP_EOL;
}