def main()

in gossip_sgd_adpsgd.py [0:0]


def main():

    global args, state, log
    args = parse_args()

    log = make_logger(args.rank, args.verbose)
    log.info('args: {}'.format(args))
    log.info(socket.gethostname())

    # seed for reproducibility
    torch.manual_seed(args.seed)
    torch.cuda.manual_seed(args.seed)
    torch.backends.cudnn.deterministic = True

    # init model, loss, and optimizer
    model = init_model()

    assert args.bilat and not args.all_reduce
    model = BilatGossipDataParallel(
        model, master_addr=args.master_addr, master_port=args.master_port,
        backend=args.backend, world_size=args.world_size, rank=args.rank,
        graph_class=args.graph_class, mixing_class=args.mixing_class,
        comm_device=args.comm_device, lr=args.lr, momentum=args.momentum,
        weight_decay=args.weight_decay, nesterov=args.nesterov,
        verbose=args.verbose, num_peers=args.ppi_schedule[0],
        network_interface_type=args.network_interface_type,
        tcp_interface_name=get_tcp_interface_name(
            network_interface_type=args.network_interface_type
        )
    )

    criterion = nn.CrossEntropyLoss().cuda()
    optimizer = torch.optim.SGD(model.parameters(),
                                lr=args.lr,
                                momentum=args.momentum,
                                weight_decay=args.weight_decay,
                                nesterov=args.nesterov)
    optimizer.zero_grad()

    # dictionary used to encode training state
    state = {}
    update_state(state, {
            'epoch': 0, 'itr': 0, 'best_prec1': 0, 'is_best': True,
            'state_dict': model.state_dict(),
            'optimizer': optimizer.state_dict(),
            'elapsed_time': 0,
            'batch_meter': Meter(ptag='Time').__dict__,
            'data_meter': Meter(ptag='Data').__dict__,
            'nn_meter': Meter(ptag='Forward/Backward').__dict__
    })

    # module used to relaunch jobs and handle external termination signals
    cmanager = ClusterManager(rank=args.rank,
                              world_size=args.world_size,
                              model_tag=args.tag,
                              state=state,
                              all_workers=args.checkpoint_all)

    # resume from checkpoint
    if args.resume:
        if os.path.isfile(cmanager.checkpoint_fpath):
            log.info("=> loading checkpoint '{}'"
                     .format(cmanager.checkpoint_fpath))
            checkpoint = torch.load(cmanager.checkpoint_fpath)
            update_state(state, {
                          'epoch': checkpoint['epoch'],
                          'itr': checkpoint['itr'],
                          'best_prec1': checkpoint['best_prec1'],
                          'is_best': False,
                          'state_dict': checkpoint['state_dict'],
                          'optimizer': checkpoint['optimizer'],
                          'elapsed_time': checkpoint['elapsed_time'],
                          'batch_meter': checkpoint['batch_meter'],
                          'data_meter': checkpoint['data_meter'],
                          'nn_meter': checkpoint['nn_meter']
            })
            model.load_state_dict(checkpoint['state_dict'])
            optimizer.load_state_dict(checkpoint['optimizer'])
            log.info("=> loaded checkpoint '{}' (epoch {}; itr {})"
                     .format(cmanager.checkpoint_fpath,
                             checkpoint['epoch'], checkpoint['itr']))
        else:
            log.info("=> no checkpoint found at '{}'"
                     .format(cmanager.checkpoint_fpath))

    # enable low-level optimization of compute graph using cuDNN library?
    cudnn.benchmark = True

    # meters used to compute timing stats
    batch_meter = Meter(state['batch_meter'])
    data_meter = Meter(state['data_meter'])
    nn_meter = Meter(state['nn_meter'])

    # initalize log file
    if not args.resume:
        with open(args.out_fname, 'w') as f:
            print('BEGIN-TRAINING\n'
                  'World-Size,{ws}\n'
                  'Num-DLWorkers,{nw}\n'
                  'Batch-Size,{bs}\n'
                  'Epoch,itr,BT(s),avg:BT(s),std:BT(s),'
                  'NT(s),avg:NT(s),std:NT(s),'
                  'DT(s),avg:DT(s),std:DT(s),'
                  'Loss,avg:Loss,Prec@1,avg:Prec@1,Prec@5,avg:Prec@5,val'
                  .format(ws=args.world_size,
                          nw=args.num_dataloader_workers,
                          bs=args.batch_size), file=f)

    # create distributed data loaders
    loader, sampler = make_dataloader(args, train=True)
    if not args.train_fast:
        val_loader = make_dataloader(args, train=False)

    # start all agents' training loop at same time
    model.block()
    start_itr = state['itr']
    start_epoch = state['epoch']
    elapsed_time = state['elapsed_time']
    begin_time = time.time() - state['elapsed_time']
    epoch = start_epoch
    stopping_criterion = epoch >= args.num_epochs
    while not stopping_criterion:

        # deterministic seed used to load agent's subset of data
        sampler.set_epoch(epoch + args.seed * 90)

        train(model, criterion, optimizer,
              batch_meter, data_meter, nn_meter,
              loader, epoch, start_itr, begin_time)

        start_itr = 0
        if not args.train_fast:
            # update state after each epoch
            elapsed_time = time.time() - begin_time
            update_state(state, {
                'epoch': epoch + 1, 'itr': start_itr,
                'is_best': False,
                'state_dict': model.state_dict(),
                'optimizer': optimizer.state_dict(),
                'elapsed_time': elapsed_time,
                'batch_meter': batch_meter.__dict__,
                'data_meter': data_meter.__dict__,
                'nn_meter': nn_meter.__dict__
            })
            # evaluate on validation set and save checkpoint
            prec1 = validate(val_loader, model, criterion)
            with open(args.out_fname, '+a') as f:
                print('{ep},{itr},{bt},{nt},{dt},'
                      '{filler},{filler},'
                      '{filler},{filler},'
                      '{filler},{filler},'
                      '{val}'
                      .format(ep=epoch, itr=-1,
                              bt=batch_meter,
                              dt=data_meter, nt=nn_meter,
                              filler=-1, val=prec1), file=f)
            cmanager.save_checkpoint()
            # sycnhronize models at the end of validation run
            model.block()

        epoch += 1
        stopping_criterion = args.global_epoch >= args.num_epochs

    if args.train_fast:
        val_loader = make_dataloader(args, train=False)
        prec1 = validate(val_loader, model, criterion)
        log.info('Test accuracy: {}'.format(prec1))

    log.info('elapsed_time {0}'.format(elapsed_time))