Most recent posts on home page

I found this tutorial, http://www.billerickson.net/a-better-and-easier-grid-loop/, but I’m not sure how to change it so the three columns are only on the home page.

/**
* Archive Post Class
* @since 1.0.0
*
* Breaks the posts into three columns
* @link http://www.billerickson.net/code/grid-loop-using-post-class
*
* @param array $classes
* @return array
*/
function be_archive_post_class( $classes ) {

// Don’t run on single posts or pages
if( is_singular )
return $classes;

$classes[] = ‘one-third home’;
global $wp_query;
if( 0 == $wp_query->current_post || 0 == $wp_query->current_post % 3 )
$classes[] = ‘first’;
return $classes;
}
add_filter( ‘post_class’, ‘be_archive_post_class’ );

Any help would be much appreciated.