is it possible to have the full code instead in the comments.php page

This function replaces the comment author’s link with the comment author’s profile page,
if the comment author is a registered user. Otherwise, the standard WordPress comment
author link is displayed.

This function is not mine and has been found googling.

function graphene_comment_author_profile_link(){
    /* Get the comment author information */
    global $comment;
    $comment_ID = $comment->user_id;
    $author = get_comment_author( $comment_ID );
    $url    = get_comment_author_url( $comment_ID );

    /* Return the default WordPress comment author link if comment author is not
    a registered user */
    if ($comment_ID == 0){
        if ( empty( $url ) || 'http://' == $url )
            $return = $author;
        else
            $return = "<a href="https://wordpress.stackexchange.com/questions/91506/$url" rel="external nofollow" class="url">$author</a>";
    } else {
    /* Return the link to the comment author's profile age if otherwise */
        $return = '<a href="'.home_url().'/?author=".$comment_ID."">'.$author.'</a>';
    }

    return $return;
}
add_filter('get_comment_author_link', 'graphene_comment_author_profile_link');