def main()

in benchmarks/rnnt/ootb/train/inference.py [0:0]


def main():
    parser = get_parser()
    args = parser.parse_args()

    log_fpath = args.log_file or str(Path(args.output_dir, 'nvlog_infer.json'))
    log_fpath = unique_log_fpath(log_fpath)
    dllogger.init(backends=[JSONStreamBackend(Verbosity.DEFAULT, log_fpath),
                            StdOutBackend(Verbosity.VERBOSE,
                                          metric_format=stdout_metric_format)])

    [dllogger.log("PARAMETER", {k:v}) for k,v in vars(args).items()]

    for step in ['DNN', 'data+DNN', 'data']:
        for c in [0.99, 0.95, 0.9, 0.5]:
            cs = 'avg' if c == 0.5 else f'{int(100*c)}%'
            dllogger.metadata(f'{step.lower()}_latency_{c}',
                              {'name': f'{step} latency {cs}',
                               'format': ':>7.2f', 'unit': 'ms'})
    dllogger.metadata(
        'eval_wer', {'name': 'WER', 'format': ':>3.3f', 'unit': '%'})

    if args.cpu:
        device = torch.device('cpu')
    else:
        assert torch.cuda.is_available()
        device = torch.device('cuda')
        torch.backends.cudnn.benchmark = args.cudnn_benchmark

    if args.seed is not None:
        torch.manual_seed(args.seed + args.local_rank)
        np.random.seed(args.seed + args.local_rank)
        random.seed(args.seed + args.local_rank)

    # set up distributed training
    multi_gpu = not args.cpu and int(os.environ.get('WORLD_SIZE', 1)) > 1
    if multi_gpu:
        torch.cuda.set_device(args.local_rank)
        distrib.init_process_group(backend='nccl', init_method='env://')
        print_once(f'Inference with {distrib.get_world_size()} GPUs')

    cfg = config.load(args.model_config)

    if args.max_duration is not None:
        cfg['input_val']['audio_dataset']['max_duration'] = args.max_duration
        cfg['input_val']['filterbank_features']['max_duration'] = args.max_duration

    if args.pad_to_max_duration:
        assert cfg['input_val']['audio_dataset']['max_duration'] > 0
        cfg['input_val']['audio_dataset']['pad_to_max_duration'] = True
        cfg['input_val']['filterbank_features']['pad_to_max_duration'] = True

    use_dali = args.dali_device in ('cpu', 'gpu')

    (
        dataset_kw,
        features_kw,
        splicing_kw,
        _, _
    ) = config.input(cfg, 'val')

    tokenizer_kw = config.tokenizer(cfg)
    tokenizer = Tokenizer(**tokenizer_kw)

    optim_level = 3 if args.amp else 0

    feature_proc  = torch.nn.Sequential(
        torch.nn.Identity(),
        torch.nn.Identity(),
        features.FrameSplicing(optim_level=optim_level, **splicing_kw),
        features.FillPadding(optim_level=optim_level, ),
    )

    # dataset

    data_loader = DaliDataLoader(
        gpu_id=args.local_rank or 0,
        dataset_path=args.dataset_dir,
        config_data=dataset_kw,
        config_features=features_kw,
        json_names=[args.val_manifest],
        batch_size=args.batch_size,
        sampler=dali_sampler.SimpleSampler(),
        pipeline_type="val",
        device_type=args.dali_device,
        tokenizer=tokenizer)

    model = RNNT(n_classes=tokenizer.num_labels + 1, **config.rnnt(cfg))

    if args.ckpt is not None:
        print(f'Loading the model from {args.ckpt} ...')
        checkpoint = torch.load(args.ckpt, map_location="cpu")
        key = 'ema_state_dict' if args.ema else 'state_dict'
        state_dict = checkpoint[key]
        model.load_state_dict(state_dict, strict=True)

    model.to(device)
    model.eval()

    if feature_proc is not None:
        feature_proc.to(device)
        feature_proc.eval()

    if args.amp:
        model = amp.initialize(model, opt_level='O3')

    if multi_gpu:
        model = DistributedDataParallel(model)

    agg = {'txts': [], 'preds': [], 'logits': []}
    dur = {'data': [], 'dnn': [], 'data+dnn': []}

    rep_loader = chain(*repeat(data_loader, args.repeats))
    rep_len = args.repeats * len(data_loader)

    blank_idx = tokenizer.num_labels
    greedy_decoder = RNNTGreedyDecoder(blank_idx=blank_idx)

    def sync_time():
        torch.cuda.synchronize() if device.type == 'cuda' else None
        return time.perf_counter()

    sz = []
    with torch.no_grad():

        for it, batch in enumerate(tqdm.tqdm(rep_loader, total=rep_len)):

            if use_dali:
                feats, feat_lens, txt, txt_lens = batch
                if feature_proc is not None:
                    feats, feat_lens = feature_proc([feats, feat_lens])
            else:
                batch = [t.cuda(non_blocking=True) for t in batch]
                audio, audio_lens, txt, txt_lens = batch
                feats, feat_lens = feature_proc([audio, audio_lens])
            feats = feats.permute(2, 0, 1)
            if args.amp:
                feats = feats.half()

            sz.append(feats.size(0))

            t1 = sync_time()
            log_probs, log_prob_lens = model(feats, feat_lens, txt, txt_lens)
            t2 = sync_time()

            # burn-in period; wait for a new loader due to num_workers
            if it >= 1 and (args.repeats == 1 or it >= len(data_loader)):
                dur['data'].append(t1 - t0)
                dur['dnn'].append(t2 - t1)
                dur['data+dnn'].append(t2 - t0)

            if txt is not None:
                agg['txts'] += helpers.gather_transcripts([txt], [txt_lens],
                                                          tokenizer.detokenize)

            preds = greedy_decoder.decode(model, feats, feat_lens)

            agg['preds'] += helpers.gather_predictions([preds], tokenizer.detokenize)

            if 0 < args.steps < it:
                break

            t0 = sync_time()

        # communicate the results
        if args.transcribe_wav:
            for idx,p in enumerate(agg['preds']):
                print_once(f'Prediction {idx+1: >3}: {p}')

        elif args.transcribe_filelist:
            pass

        else:
            wer, loss = process_evaluation_epoch(agg)

            if not multi_gpu or distrib.get_rank() == 0:
                dllogger.log(step=(), data={'eval_wer': 100 * wer})

        if args.save_predictions:
            with open(args.save_predictions, 'w') as f:
                f.write('\n'.join(agg['preds']))

    # report timings
    if len(dur['data']) >= 20:
        ratios = [0.9, 0.95, 0.99]

        for stage in dur:
            lat = durs_to_percentiles(dur[stage], ratios)
            for k in [0.99, 0.95, 0.9, 0.5]:
                kk = str(k).replace('.', '_')
                dllogger.log(step=(), data={f'{stage.lower()}_latency_{kk}': lat[k]})

    else:
        # TODO measure at least avg latency
        print_once('Not enough samples to measure latencies.')