Source code for chainer.links.loss.black_out

import numpy

import chainer
from chainer import cuda
from chainer.functions.loss import black_out
from chainer import link
from chainer.utils import walker_alias

[docs]class BlackOut(link.Link): """BlackOut loss layer. .. seealso:: :func:`~chainer.functions.black_out` for more detail. Args: in_size (int): Dimension of input vectors. counts (int list): Number of each identifiers. sample_size (int): Number of negative samples. Attributes: W (~chainer.Variable): Weight parameter matrix. """ def __init__(self, in_size, counts, sample_size): vocab_size = len(counts) super(BlackOut, self).__init__(W=(vocab_size, in_size)) p = numpy.array(counts, dtype=numpy.float32) self.sampler = walker_alias.WalkerAlias(p) self.sample_size = sample_size def to_cpu(self): super(BlackOut, self).to_cpu() self.sampler.to_cpu() def to_gpu(self, device=None): with cuda.get_device(device): super(BlackOut, self).to_gpu() self.sampler.to_gpu() def __call__(self, x, t): """Computes the loss value for given input and ground truth labels. Args: x (~chainer.Variable): Input of the weight matrix multiplication. t (~chainer.Variable): Batch of ground truth labels. Returns: ~chainer.Variable: Loss value. """ batch_size = x.shape[0] if hasattr(self, 'sample_data'): # for test sample_data = self.sample_data else: shape = (batch_size, self.sample_size) sample_data = self.sampler.sample(shape) samples = chainer.Variable(sample_data) return black_out.black_out(x, t, self.W, samples)