Files
NALU-pytorch/models/nac.py
T
2018-08-04 02:53:30 -07:00

44 lines
1.3 KiB
Python

import math
import torch
import torch.nn as nn
import torch.nn.init as init
import torch.nn.functional as F
from torch.nn.parameter import Parameter
class NAC(nn.Module):
"""A Neural Accumulator [1].
NAC supports the ability to accumulate quantities
additively which is a desirable inductive bias for
linear extrapolation.
Attributes:
in_features: size of the input sample.
out_features: size of the output sample.
Sources:
[1]: https://arxiv.org/abs/1808.00508
"""
def __init__(self, in_features, out_features):
super().__init__()
self.in_features = in_features
self.out_features = out_features
self.W_hat = Parameter(torch.Tensor(out_features, in_features))
self.M_hat = Parameter(torch.Tensor(out_features, in_features))
self.W = Parameter(F.tanh(self.W_hat) * F.sigmoid(self.M_hat))
self.register_parameter('bias', None)
init.kaiming_uniform_(self.W_hat, a=math.sqrt(5))
init.kaiming_uniform_(self.M_hat, a=math.sqrt(5))
def forward(self, input):
return F.linear(input, self.W, self.bias)
def extra_repr(self):
return 'in_features={}, out_features={}'.format(
self.in_features, self.out_features
)