wehub-resource-sync
228 lines
8.9 KiB
Python
228 lines
8.9 KiB
Python
# Copyright (c) Facebook, Inc. and its affiliates.
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#
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# This source code is licensed under the MIT license found in the
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# LICENSE file in the root directory of this source tree.
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import dynamicconv_cuda
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import torch
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import torch.nn.functional as F
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from fairseq import utils
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from fairseq.incremental_decoding_utils import with_incremental_state
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from fairseq.modules.fairseq_dropout import FairseqDropout
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from fairseq.modules.unfold import unfold1d
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from torch import nn
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from torch.autograd import Function
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class dynamicconvFunction(Function):
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@staticmethod
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def forward(ctx, x, weights, padding_l):
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ctx.padding_l = padding_l
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outputs = dynamicconv_cuda.forward(x, weights, padding_l)
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variables = [x, weights]
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ctx.save_for_backward(*variables)
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return outputs[0]
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@staticmethod
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def backward(ctx, grad_output):
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outputs = dynamicconv_cuda.backward(
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grad_output.contiguous(), ctx.padding_l, *ctx.saved_tensors
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)
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grad_input, grad_weights = outputs
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return grad_input, grad_weights, None
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@with_incremental_state
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class DynamicconvLayer(nn.Module):
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def __init__(
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self,
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input_size,
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kernel_size=1,
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padding_l=None,
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weight_softmax=False,
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num_heads=1,
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weight_dropout=0.0,
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bias=False,
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renorm_padding=False,
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conv_bias=False,
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query_size=None,
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):
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super(DynamicconvLayer, self).__init__()
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self.input_size = input_size
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self.query_size = input_size if query_size is None else query_size
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self.kernel_size = kernel_size
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self.padding_l = padding_l
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self.num_heads = num_heads
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self.weight_softmax = weight_softmax
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self.weight_dropout_module = FairseqDropout(
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weight_dropout, module_name=self.__class__.__name__
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)
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self.renorm_padding = renorm_padding
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self.bias = bias
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self.weight_linear = nn.Linear(input_size, num_heads * kernel_size, bias)
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if conv_bias:
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self.conv_bias = nn.Parameter(torch.Tensor(input_size))
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else:
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self.conv_bias = None
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self.reset_parameters()
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def reset_parameters(self):
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nn.init.xavier_uniform_(self.weight_linear.weight)
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if self.conv_bias is not None:
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nn.init.constant_(self.conv_bias, 0.0)
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nn.init.constant_(self.weight_linaer.bias, 0.0)
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def forward(self, x, incremental_state=None, query=None, unfold=None):
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T, B, C = x.size()
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K, H = self.kernel_size, self.num_heads
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# R = C // H
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# during inference time, incremental BMM is faster
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if incremental_state is not None:
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unfold = (
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x.size(0) > 512 if unfold is None else unfold
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) # use unfold mode as default for long sequence to save memory
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unfold = unfold or (incremental_state is not None)
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assert query is None
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if query is None:
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query = x
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if unfold:
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output = self._forward_unfolded(x, incremental_state, query)
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else:
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output = self._forward_expanded(x, incremental_state, query)
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if self.conv_bias is not None:
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output = output + self.conv_bias.view(1, 1, -1)
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return output
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# during training time, use CUDA kernel
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else:
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weight = self.weight_linear(x).view(T, B, H, K)
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if self.weight_softmax:
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weight = F.softmax(weight, dim=-1)
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if self.weight_dropout_module.p:
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weight = self.weight_dropout_module(weight)
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weight = weight.permute(1, 2, 3, 0).contiguous()
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self.filters = weight
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x = x.permute(1, 2, 0).contiguous()
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output = dynamicconvFunction.apply(x, weight, self.padding_l).permute(
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2, 0, 1
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)
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if self.conv_bias is not None:
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output = output + self.conv_bias.view(1, 1, -1)
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return output
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def reorder_incremental_state(self, incremental_state, new_order):
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input_buffer = self._get_input_buffer(incremental_state)
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if input_buffer is not None:
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input_buffer = input_buffer.index_select(1, new_order)
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self._set_input_buffer(incremental_state, input_buffer)
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def _get_input_buffer(self, incremental_state):
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return utils.get_incremental_state(self, incremental_state, "input_buffer")
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def _set_input_buffer(self, incremental_state, new_buffer):
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return utils.set_incremental_state(
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self, incremental_state, "input_buffer", new_buffer
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)
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def _forward_unfolded(self, x, incremental_state, query):
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"""The conventional implementation of convolutions.
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Unfolding the input by having a window shifting to the right."""
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T, B, C = x.size()
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K, H = self.kernel_size, self.num_heads
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R = C // H
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assert R * H == C == self.input_size
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weight = self.weight_linear(query).view(T * B * H, -1)
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# renorm_padding is only implemented in _forward_expanded
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assert not self.renorm_padding or incremental_state is not None
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if incremental_state is not None:
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input_buffer = self._get_input_buffer(incremental_state)
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if input_buffer is None:
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input_buffer = x.new()
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x_unfold = torch.cat([input_buffer, x.unsqueeze(3)], dim=3)
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if self.kernel_size > 1:
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self._set_input_buffer(
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incremental_state, x_unfold[:, :, :, -self.kernel_size + 1 :]
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)
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x_unfold = x_unfold.view(T * B * H, R, -1)
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else:
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padding_l = self.padding_l
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if K > T and padding_l == K - 1:
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weight = weight.narrow(1, K - T, T)
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K, padding_l = T, T - 1
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# unfold the input: T x B x C --> T' x B x C x K
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x_unfold = unfold1d(x, K, padding_l, 0)
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x_unfold = x_unfold.view(T * B * H, R, K)
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if self.weight_softmax and not self.renorm_padding:
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weight = F.softmax(weight, dim=1)
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weight = weight.narrow(1, 0, K)
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if incremental_state is not None:
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weight = weight[:, -x_unfold.size(2) :]
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K = weight.size(1)
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if self.weight_softmax and self.renorm_padding:
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weight = F.softmax(weight, dim=1)
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weight = self.weight_dropout_module(weight, inplace=False)
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output = torch.bmm(x_unfold, weight.unsqueeze(2)) # T*B*H x R x 1
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output = output.view(T, B, C)
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return output
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def _forward_expanded(self, x, incremental_stat, query):
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"""Turn the convolution filters into band matrices and do matrix multiplication.
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This is faster when the sequence is short, but less memory efficient.
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This is not used in the decoder during inference.
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"""
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T, B, C = x.size()
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K, H = self.kernel_size, self.num_heads
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R = C // H
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assert R * H == C == self.input_size
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weight = self.weight_linear(query).view(T * B * H, -1)
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if not self.renorm_padding:
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if self.weight_softmax:
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weight = F.softmax(weight, dim=1)
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weight = self.weight_dropout_module(weight, inplace=False)
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weight = weight.narrow(1, 0, K).contiguous()
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weight = weight.view(T, B * H, K).transpose(0, 1)
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x = x.view(T, B * H, R).transpose(0, 1)
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if self.weight_softmax and self.renorm_padding:
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# turn the convolution filters into band matrices
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weight_expanded = weight.new(B * H, T, T + K - 1).fill_(float("-inf"))
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weight_expanded.as_strided(
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(B * H, T, K), (T * (T + K - 1), T + K, 1)
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).copy_(weight)
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weight_expanded = weight_expanded.narrow(2, self.padding_l, T)
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# normalize the weight over valid positions like self-attention
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weight_expanded = F.softmax(weight_expanded, dim=2)
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weight_expanded = self.weight_dropout_module(weight_expanded, inplace=False)
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else:
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P = self.padding_l
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# For efficiency, we cut the kernel size and reduce the padding when the kernel is larger than the length
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if K > T and P == K - 1:
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weight = weight.narrow(2, K - T, T)
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K, P = T, T - 1
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# turn the convolution filters into band matrices
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weight_expanded = weight.new_zeros(B * H, T, T + K - 1, requires_grad=False)
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weight_expanded.as_strided(
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(B * H, T, K), (T * (T + K - 1), T + K, 1)
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).copy_(weight)
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weight_expanded = weight_expanded.narrow(2, P, T) # B*H x T x T
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output = torch.bmm(weight_expanded, x)
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output = output.transpose(0, 1).contiguous().view(T, B, C)
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return output
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