if( ! function_exists( 'mars_pagination' ) && function_exists( 'wp_pagenavi' ) ){
    /**
     * Replace the default pagination by wp_pagenavi plugin.
     * @param unknown_type $query
     */
    function mars_pagination( $query = null ) {
        $args = array(
            'echo'  =>  true
        );
        if( ! empty( $query ) ){
            $args['query']  =   $query;
        }
        wp_pagenavi( $args );
    }
    add_action('mars_pagination', 'mars_pagination', 10, 1);
}