Add Initial support for ContextNet Encoder and CTC Decoder

CHANGELOG.md

@@ -76,6 +76,7 @@ To release a new version, please update the changelog as followed:
 - Speed augmentation on CPU, TimeStretch augmentation on CPU+GPU ([PR #594](https://github.com/NVIDIA/NeMo/pull/565)) - @titu1994
 - Added TarredAudioToTextDataLayer, which allows for loading ASR datasets with tarred audio. Existing datasets can be converted with the `convert_to_tarred_audio_dataset.py` script. ([PR #602](https://github.com/NVIDIA/NeMo/pull/602))
 - Online audio augmentation notebook in ASR examples ([PR #605](https://github.com/NVIDIA/NeMo/pull/605)) - @titu1994
+- ContextNet Encoder + Decoder Initial Support ([PR #630](https://github.com/NVIDIA/NeMo/pull/630)) - @titu1994
 
 ### Changed
 

examples/asr/contextnet.py

@@ -0,0 +1,293 @@
+# Copyright (c) 2019 NVIDIA Corporation
+import argparse
+import copy
+import os
+from functools import partial
+
+from ruamel.yaml import YAML
+
+import nemo
+import nemo.collections.asr as nemo_asr
+import nemo.utils.argparse as nm_argparse
+from nemo.collections.asr.helpers import monitor_asr_train_progress, process_evaluation_batch, process_evaluation_epoch
+from nemo.utils.lr_policies import CosineAnnealing
+
+logging = nemo.logging
+
+
+def parse_args():
+    parser = argparse.ArgumentParser(
+        parents=[nm_argparse.NemoArgParser()], description='ContextNet', conflict_handler='resolve',
+    )
+    parser.set_defaults(
+        checkpoint_dir=None,
+        optimizer="novograd",
+        batch_size=32,
+        eval_batch_size=64,
+        lr=0.01,
+        weight_decay=0.001,
+        amp_opt_level="O0",
+        create_tb_writer=True,
+    )
+
+    # Overwrite default args
+    parser.add_argument(
+        "--num_epochs",
+        type=int,
+        default=None,
+        required=True,
+        help="number of epochs to train. You should specify either num_epochs or max_steps",
+    )
+    parser.add_argument(
+        "--model_config", type=str, required=True, help="model configuration file: model.yaml",
+    )
+
+    # Create new args
+    parser.add_argument("--exp_name", default="ContextNet", type=str)
+    parser.add_argument("--beta1", default=0.95, type=float)
+    parser.add_argument("--beta2", default=0.5, type=float)
+    parser.add_argument("--warmup_steps", default=1000, type=int)
+    parser.add_argument('--min_lr', default=1e-3, type=float)
+    parser.add_argument("--load_dir", default=None, type=str)
+    parser.add_argument("--synced_bn", action='store_true', help="Use synchronized batch norm")
+    parser.add_argument("--synced_bn_groupsize", default=0, type=int)
+    parser.add_argument('--kernel_size_factor', default=1.0, type=float)
+
+    args = parser.parse_args()
+    if args.max_steps is not None:
+        raise ValueError("ContextNet uses num_epochs instead of max_steps")
+
+    return args
+
+
+def construct_name(name, lr, batch_size, num_epochs, wd, optimizer, kernel_size_factor):
+    return "{0}-lr_{1}-bs_{2}-e_{3}-wd_{4}-opt_{5}-kf_{6}".format(
+        name, lr, batch_size, num_epochs, wd, optimizer, kernel_size_factor
+    )
+
+
+def create_all_dags(args, neural_factory):
+    '''
+    creates train and eval dags as well as their callbacks
+    returns train loss tensor and callbacks'''
+
+    # parse the config files
+    yaml = YAML(typ="safe")
+    with open(args.model_config) as f:
+        contextnet_params = yaml.load(f)
+
+    vocab = contextnet_params['labels']
+    sample_rate = contextnet_params['sample_rate']
+
+    # Calculate num_workers for dataloader
+    total_cpus = os.cpu_count()
+    cpu_per_traindl = max(int(total_cpus / neural_factory.world_size), 1)
+
+    # create data layer for training
+    train_dl_params = copy.deepcopy(contextnet_params["AudioToTextDataLayer"])
+    train_dl_params.update(contextnet_params["AudioToTextDataLayer"]["train"])
+    del train_dl_params["train"]
+    del train_dl_params["eval"]
+    # del train_dl_params["normalize_transcripts"]
+
+    data_layer_train = nemo_asr.AudioToTextDataLayer(
+        manifest_filepath=args.train_dataset,
+        sample_rate=sample_rate,
+        labels=vocab,
+        batch_size=args.batch_size,
+        num_workers=cpu_per_traindl,
+        **train_dl_params,
+        # normalize_transcripts=False
+    )
+
+    N = len(data_layer_train)
+    steps_per_epoch = int(N / (args.batch_size * args.iter_per_step * args.num_gpus))
+
+    # create separate data layers for eval
+    # we need separate eval dags for separate eval datasets
+    # but all other modules in these dags will be shared
+
+    eval_dl_params = copy.deepcopy(contextnet_params["AudioToTextDataLayer"])
+    eval_dl_params.update(contextnet_params["AudioToTextDataLayer"]["eval"])
+    del eval_dl_params["train"]
+    del eval_dl_params["eval"]
+
+    data_layers_eval = []
+    if args.eval_datasets:
+        for eval_dataset in args.eval_datasets:
+            data_layer_eval = nemo_asr.AudioToTextDataLayer(
+                manifest_filepath=eval_dataset,
+                sample_rate=sample_rate,
+                labels=vocab,
+                batch_size=args.eval_batch_size,
+                num_workers=cpu_per_traindl,
+                **eval_dl_params,
+            )
+
+            data_layers_eval.append(data_layer_eval)
+    else:
+        logging.warning("There were no val datasets passed")
+
+    # create shared modules
+
+    data_preprocessor = nemo_asr.AudioToMelSpectrogramPreprocessor(
+        sample_rate=sample_rate, **contextnet_params["AudioToMelSpectrogramPreprocessor"],
+    )
+
+    # Inject the `kernel_size_factor` kwarg to the ContextNet config
+    # Skip the last layer  as that must be a pointwise kernel
+    for idx in range(len(contextnet_params["ContextNetEncoder"]["jasper"]) - 1):
+        contextnet_params["ContextNetEncoder"]["jasper"][idx]["kernel_size_factor"] = args.kernel_size_factor
+
+    # (ContextNet uses the Jasper baseline encoder and decoder)
+    encoder = nemo_asr.ContextNetEncoder(
+        feat_in=contextnet_params["AudioToMelSpectrogramPreprocessor"]["features"],
+        **contextnet_params["ContextNetEncoder"],
+    )
+
+    decoder = nemo_asr.JasperDecoderForCTC(
+        feat_in=contextnet_params["ContextNetEncoder"]["jasper"][-1]["filters"], num_classes=len(vocab),
+    )
+
+    ctc_loss = nemo_asr.CTCLossNM(num_classes=len(vocab), zero_infinity=True)
+
+    greedy_decoder = nemo_asr.GreedyCTCDecoder()
+
+    # create augmentation modules (only used for training) if their configs
+    # are present
+
+    multiply_batch_config = contextnet_params.get('MultiplyBatch', None)
+    if multiply_batch_config:
+        multiply_batch = nemo_asr.MultiplyBatch(**multiply_batch_config)
+
+    spectr_augment_config = contextnet_params.get('SpectrogramAugmentation', None)
+    if spectr_augment_config:
+        data_spectr_augmentation = nemo_asr.SpectrogramAugmentation(**spectr_augment_config)
+
+    # assemble train DAG
+
+    (audio_signal_t, a_sig_length_t, transcript_t, transcript_len_t,) = data_layer_train()
+
+    processed_signal_t, p_length_t = data_preprocessor(input_signal=audio_signal_t, length=a_sig_length_t)
+
+    if multiply_batch_config:
+        (processed_signal_t, p_length_t, transcript_t, transcript_len_t,) = multiply_batch(
+            in_x=processed_signal_t, in_x_len=p_length_t, in_y=transcript_t, in_y_len=transcript_len_t,
+        )
+
+    if spectr_augment_config:
+        processed_signal_t = data_spectr_augmentation(input_spec=processed_signal_t)
+
+    encoded_t, encoded_len_t = encoder(audio_signal=processed_signal_t, length=p_length_t)
+    log_probs_t = decoder(encoder_output=encoded_t)
+    predictions_t = greedy_decoder(log_probs=log_probs_t)
+    loss_t = ctc_loss(
+        log_probs=log_probs_t, targets=transcript_t, input_length=encoded_len_t, target_length=transcript_len_t,
+    )
+
+    # create train callbacks
+    train_callback = nemo.core.SimpleLossLoggerCallback(
+        tensors=[loss_t, predictions_t, transcript_t, transcript_len_t],
+        print_func=partial(monitor_asr_train_progress, labels=vocab),
+        get_tb_values=lambda x: [["loss", x[0]]],
+        tb_writer=neural_factory.tb_writer,
+    )
+
+    callbacks = [train_callback]
+
+    if args.checkpoint_dir or args.load_dir:
+        chpt_callback = nemo.core.CheckpointCallback(
+            folder=args.checkpoint_dir, load_from_folder=args.load_dir, step_freq=args.checkpoint_save_freq,
+        )
+
+        callbacks.append(chpt_callback)
+
+    # assemble eval DAGs
+    for i, eval_dl in enumerate(data_layers_eval):
+        (audio_signal_e, a_sig_length_e, transcript_e, transcript_len_e,) = eval_dl()
+        processed_signal_e, p_length_e = data_preprocessor(input_signal=audio_signal_e, length=a_sig_length_e)
+        encoded_e, encoded_len_e = encoder(audio_signal=processed_signal_e, length=p_length_e)
+        log_probs_e = decoder(encoder_output=encoded_e)
+        predictions_e = greedy_decoder(log_probs=log_probs_e)
+        loss_e = ctc_loss(
+            log_probs=log_probs_e, targets=transcript_e, input_length=encoded_len_e, target_length=transcript_len_e,
+        )
+
+        # create corresponding eval callback
+        tagname = os.path.basename(args.eval_datasets[i]).split(".")[0]
+
+        eval_callback = nemo.core.EvaluatorCallback(
+            eval_tensors=[loss_e, predictions_e, transcript_e, transcript_len_e,],
+            user_iter_callback=partial(process_evaluation_batch, labels=vocab),
+            user_epochs_done_callback=partial(process_evaluation_epoch, tag=tagname),
+            eval_step=args.eval_freq,
+            tb_writer=neural_factory.tb_writer,
+        )
+
+        callbacks.append(eval_callback)
+
+    return loss_t, callbacks, steps_per_epoch
+
+
+def main():
+    args = parse_args()
+
+    name = construct_name(
+        args.exp_name,
+        args.lr,
+        args.batch_size,
+        args.num_epochs,
+        args.weight_decay,
+        args.optimizer,
+        args.kernel_size_factor,
+    )
+    work_dir = name
+    if args.work_dir:
+        work_dir = os.path.join(args.work_dir, name)
+
+    # instantiate Neural Factory with supported backend
+    neural_factory = nemo.core.NeuralModuleFactory(
+        backend=nemo.core.Backend.PyTorch,
+        local_rank=args.local_rank,
+        optimization_level=args.amp_opt_level,
+        log_dir=work_dir,
+        checkpoint_dir=args.checkpoint_dir,
+        create_tb_writer=args.create_tb_writer,
+        files_to_copy=[args.model_config, __file__],
+        cudnn_benchmark=args.cudnn_benchmark,
+        tensorboard_dir=args.tensorboard_dir,
+    )
+    args.num_gpus = neural_factory.world_size
+
+    args.checkpoint_dir = neural_factory.checkpoint_dir
+
+    if args.local_rank is not None:
+        logging.info('Doing ALL GPU')
+
+    # build dags
+    train_loss, callbacks, steps_per_epoch = create_all_dags(args, neural_factory)
+
+    # train model
+    neural_factory.train(
+        tensors_to_optimize=[train_loss],
+        callbacks=callbacks,
+        lr_policy=CosineAnnealing(
+            args.num_epochs * steps_per_epoch, warmup_steps=args.warmup_steps, min_lr=args.min_lr
+        ),
+        optimizer=args.optimizer,
+        optimization_params={
+            "num_epochs": args.num_epochs,
+            "lr": args.lr,
+            "betas": (args.beta1, args.beta2),
+            "weight_decay": args.weight_decay,
+            "grad_norm_clip": None,
+            "amp_min_loss_scale": 1e-4,
+        },
+        batches_per_step=args.iter_per_step,
+        synced_batchnorm=args.synced_bn,
+        synced_batchnorm_groupsize=args.synced_bn_groupsize,
+    )
+
+
+if __name__ == '__main__':
+    main()

nemo/collections/asr/__init__.py

@@ -14,6 +14,7 @@
 # =============================================================================
 from .audio_preprocessing import *
 from .beam_search_decoder import BeamSearchDecoderWithLM
+from .contextnet import ContextNetDecoderForCTC, ContextNetEncoder
 from .data_layer import (
     AudioToSpeechLabelDataLayer,
     AudioToTextDataLayer,
@@ -50,6 +51,8 @@
     'JasperDecoderForClassification',
     'JasperDecoderForSpkrClass',
     'JasperRNNConnector',
+    'ContextNetEncoder',
+    'ContextNetDecoderForCTC',
     'CTCLossNM',
     'CrossEntropyLossNM',
 ]