MyMasterController *masterViewController = [[[MyMasterController alloc] initWithDirectory:directoryElement] autorelease];

        MyDetailController *detailViewController = [[MyDetailController alloc] init];


        masterViewController.detailViewController = detailViewController;

        UISplitViewController *splitViewController = [[UISplitViewController alloc] init];
        splitViewController.viewControllers = @[[[UINavigationController alloc] initWithRootViewController:masterViewController], [[UINavigationController alloc] initWithRootViewController:detailViewController]
                                             ];
        splitViewController.delegate = self;

- (void) tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
   [master some_method]; // how to get ?
}

-(void) viewDidLoad {

    ...
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(someMethod) name:@"DoSomeMethod" object:nil];

}

-(void) someMethod {

    ...

}

- (void) tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {

   [[NSNotificationCenter defaultCenter] postNotificationName:@"DoSomeMethod" object:nil];

}