how can i reduce the memory usage in php code?

[shikha y]

echo '<li>first--'.memory_get_usage();
require_once('smarty_si.php');
echo '<li>after smarty--'.memory_get_usage();
echo'<li>';
$smarty = new Smarty_si();
$smarty->assign("name","you memory leak !!! You r leaking all over the place.......");
$i=0;
echo '<li>before display'.memory_get_usage();
$smarty->display('testleak.tpl',"kumar");
$smarty->clear_cache('testleak.tpl');
$smarty->clear_cache(null,