## @package position_weighted
# Module caffe2.python.layers.position_weighted
import logging
import numpy as np
from caffe2.python import schema
from caffe2.python.layers.layers import (
get_categorical_limit,
ModelLayer,
)
from caffe2.python.layers.tags import Tags
logger = logging.getLogger(__name__)
class PositionWeighted(ModelLayer):
def __init__(self, model, input_record, weight_optim=None,
name="position_weights"):
super(PositionWeighted, self).__init__(model, name, input_record)
assert isinstance(input_record, schema.List), "Incorrect input type"
length_metadata = input_record.lengths.metadata
max_length = (length_metadata.categorical_limit if length_metadata is
not None else None)
if max_length is not None:
self.shape = max_length
else:
self.shape = get_categorical_limit(input_record)
logger.warning(
'{}: categorical_limit of lengths is not available, using '
'categorical_limit of the keys: {}'.format(
str(input_record.lengths()), self.shape))
self.pos_w = self.create_param(param_name='pos_w',
shape=[self.shape, ],
initializer=('ConstantFill', {'value': 1.0}),
optimizer=weight_optim)
self.output_schema = schema.Struct(
('position_weights',
schema.Scalar((np.float32, self.shape),
self.get_next_blob_reference("pos_w_gather")))
)
self.tags.update({Tags.HANDLE_AS_SPARSE_LAYER})
def get_memory_usage(self):
return self.shape
def add_ops(self, net):
inc_seq = net.LengthsRangeFill(
[self.input_record.lengths()],
self.input_record.lengths() + '_pos_w_seq'
)
net.Gather(
[self.pos_w, inc_seq],
self.output_schema.position_weights.field_blobs())