official/projects/perceiver/tasks/pretrain.py
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"""Task for perceiver wordpiece tokenized masked language model (MLM)."""
import tensorflow as tf, tf_keras
from official.core import task_factory
from official.modeling import tf_utils
from official.nlp.tasks import masked_lm
from official.projects.perceiver.configs import encoders
from official.projects.perceiver.configs import perceiver
from official.projects.perceiver.modeling.layers import decoder
from official.projects.perceiver.modeling.models import pretrainer
from official.projects.perceiver.modeling.networks import positional_decoder
@task_factory.register_task_cls(perceiver.PretrainConfig)
class PretrainTask(masked_lm.MaskedLMTask):
"""Task for masked language modeling for wordpiece tokenized perceiver."""
def build_model(self, params=None):
"""Creates perceiver pretrainer model architecture.
Args:
params:
The task configuration instance, which can be any of dataclass,
ConfigDict, namedtuple, etc.
Returns:
A model instance.
"""
config = params or self.task_config.model
sequence_encoder_cfg = config.encoder
encoder_network = encoders.build_encoder(sequence_encoder_cfg)
decoder_cfg = config.decoder
decoder_ = decoder.Decoder(decoder_cfg.decoder.as_dict())
mlm_decoder = positional_decoder.PositionalDecoder(
decoder=decoder_,
output_index_dim=decoder_cfg.output_index_dim,
z_index_dim=decoder_cfg.z_index_dim,
d_latents=decoder_cfg.d_latents,
d_model=decoder_cfg.d_model,
position_encoding_intializer_stddev=decoder_cfg
.position_encoding_intializer_stddev)
return pretrainer.Pretrainer(
mlm_activation=tf_utils.get_activation(config.mlm_activation),
mlm_initializer=tf_keras.initializers.TruncatedNormal(
stddev=config.mlm_initializer_range),
encoder=encoder_network,
decoder=mlm_decoder)