isotope.js acting more responsively

resize.isotope.js

$( this ).imagesLoaded(function() {		
  $container = $( '#container' );
		
	function gallery_item_width() {
		width = Math.floor( ($('#primary').width()) / 3 );
		$( '#container .item' ).width( width + 'px' );
	}
	
	$(window).smartresize( gallery_item_width() );

	$container.isotope({
		itemSelector : '.item',
		masonry: {
    		columnWidth:  gallery_item_width()
  		}
	});
});