import logging
import math
from typing import Dict, List
import numpy
from allennlp.common.util import pad_sequence_to_length
from allennlp.data.fields.field import Field
from overrides import overrides
logger = logging.getLogger(__name__)
class FeaturesField(Field[numpy.ndarray]):
"""An AllenNLP field for fixed-length feature vectors"""
def __init__(self, features: List[float]) -> None:
self.features = features
@overrides
def get_padding_lengths(self) -> Dict[str, int]:
return {'num_features': len(self.features)}
@overrides
def as_array(self, padding_lengths: Dict[str, int]) -> numpy.array:
padded_features = pad_sequence_to_length(self.features,
padding_lengths['num_features'],
(lambda: math.nan))
return numpy.asarray(padded_features, dtype=numpy.float32)
@overrides
def empty_field(self):
return FeaturesField([math.nan] * len(self.features))
