Files
Clover-Edition/generator/ctrl/pytorch_transformer.py
T
2019-09-27 14:39:18 -06:00

144 lines
4.3 KiB
Python

from __future__ import print_function
import torch
import os
import tqdm
import pdb
import numpy as np
import platform
import re
import argparse
import tensorflow as tf
from tensorflow.python import pywrap_tensorflow
def angle_defn(pos, i, d_model_size):
angle_rates = 1 / np.power(10000, (2 * (i//2)) / np.float32(d_model_size))
return pos * angle_rates
def positional_encoding(position, d_model_size):
# create the sinusoidal pattern for the positional encoding
angle_rads = angle_defn(np.arange(position)[:, np.newaxis], np.arange(d_model_size)[np.newaxis, :], d_model_size)
sines = np.sin(angle_rads[:, 0::2])
cosines = np.cos(angle_rads[:, 1::2])
pos_encoding = torch.tensor(np.concatenate([sines, cosines], axis=-1)[np.newaxis, ...], dtype=torch.float)
return pos_encoding
def scaled_dot_product_attention(q, k, v, mask):
# calculate attention
matmul_qk = torch.matmul(q, k.permute(0,1,3,2))
dk = k.shape[-1]
scaled_attention_logits = matmul_qk / np.sqrt(dk)
if mask is not None:
scaled_attention_logits += (mask * -1e9)
attention_weights = torch.softmax(scaled_attention_logits, dim=-1)
output = torch.matmul(attention_weights, v)
return output
class MultiHeadAttention(torch.nn.Module):
def __init__(self, d_model_size, num_heads):
super(MultiHeadAttention, self).__init__()
self.num_heads = num_heads
self.d_model_size = d_model_size
self.depth = int(d_model_size / self.num_heads)
self.Wq = torch.nn.Linear(d_model_size, d_model_size)
self.Wk = torch.nn.Linear(d_model_size, d_model_size)
self.Wv = torch.nn.Linear(d_model_size, d_model_size)
self.dense = torch.nn.Linear(d_model_size, d_model_size)
def split_into_heads(self, x, batch_size):
x = x.reshape(batch_size, -1, self.num_heads, self.depth)
return x.permute([0, 2, 1, 3])
def forward(self, v, k, q, mask):
batch_size = q.shape[0]
q = self.Wq(q)
k = self.Wk(k)
v = self.Wv(v)
q = self.split_into_heads(q, batch_size)
k = self.split_into_heads(k, batch_size)
v = self.split_into_heads(v, batch_size)
scaled_attention = scaled_dot_product_attention(q, k, v, mask).permute([0, 2, 1, 3])
original_size_attention = scaled_attention.reshape(batch_size, -1, self.d_model_size)
output = self.dense(original_size_attention)
return output
def point_wise_feed_forward_network(d_model_size, dff):
return torch.nn.Sequential(torch.nn.Linear(d_model_size, dff), torch.nn.ReLU(), torch.nn.Linear(dff, d_model_size))
class EncoderLayer(torch.nn.Module):
def __init__(self, d_model_size, num_heads, dff, rate=0.1):
super(EncoderLayer, self).__init__()
self.multi_head_attention = MultiHeadAttention(d_model_size, num_heads)
self.ffn = point_wise_feed_forward_network(d_model_size, dff)
self.layernorm1 = torch.nn.LayerNorm(d_model_size, eps=1e-6)
self.layernorm2 = torch.nn.LayerNorm(d_model_size, eps=1e-6)
self.dropout1 = torch.nn.Dropout(rate)
self.dropout2 = torch.nn.Dropout(rate)
def forward(self, x, mask):
normed = self.layernorm1(x)
attn_output = self.multi_head_attention(normed, normed, normed, mask)
attn_output = self.dropout1(attn_output)
out1 = x + attn_output
out2 = self.layernorm2(out1)
ffn_output = self.ffn(out2)
ffn_output = self.dropout2(ffn_output)
out2 = out1 + ffn_output
return out2
class Encoder(torch.nn.Module):
def __init__(self, num_layers=48, d_model_size=1280, num_heads=16, dff=8192, input_vocab_size=50000,
rate=0.1, **kwargs):
super(Encoder, self).__init__()
self.d_model_size = d_model_size
self.num_layers = num_layers
self.pos_encoding = positional_encoding(input_vocab_size, self.d_model_size).to('cuda')
for i in range(num_layers):
setattr(self, "layer%i" % i, EncoderLayer(d_model_size, num_heads, dff, rate))
self.layernorm = torch.nn.LayerNorm(d_model_size, eps=1e-6)
self.dropout = torch.nn.Dropout(rate)
def forward(self, x):
seq_len = x.shape[1]
mask = torch.triu(torch.ones(seq_len, seq_len), 1).to('cuda')
x *= np.sqrt(self.d_model_size)
x += self.pos_encoding[:, :seq_len, :]
x = self.dropout(x)
for i in range(self.num_layers):
x = getattr(self, "layer%i" % i)(x, mask)
return self.layernorm(x)