Added script for training a discriminator for pplm to use
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@ -34,6 +34,7 @@ import torch.nn.functional as F
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from torch.autograd import Variable
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from tqdm import trange
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from examples.run_pplm_discrim_train import ClassificationHead
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from transformers import GPT2Tokenizer
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from transformers.file_utils import cached_path
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from transformers.modeling_gpt2 import GPT2LMHeadModel
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@ -108,24 +109,6 @@ def top_k_filter(logits, k, probs=False):
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logits)
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class ClassificationHead(torch.nn.Module):
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""" Classification Head for the transformer """
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def __init__(self, class_size=5, embed_size=2048):
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super(ClassificationHead, self).__init__()
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self.class_size = class_size
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self.embed_size = embed_size
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# self.mlp1 = torch.nn.Linear(embed_size, embed_size)
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# self.mlp2 = (torch.nn.Linear(embed_size, class_size))
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self.mlp = torch.nn.Linear(embed_size, class_size)
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def forward(self, hidden_state):
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# hidden_state = F.relu(self.mlp1(hidden_state))
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# hidden_state = self.mlp2(hidden_state)
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logits = self.mlp(hidden_state)
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return logits
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def perturb_past(past, model, prev, args, classifier, good_index=None,
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stepsize=0.01, vocab_size=50257,
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original_probs=None, accumulated_hidden=None, true_past=None,
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@ -0,0 +1,582 @@
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#! /usr/bin/env python3
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# coding=utf-8
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# This code is licensed under a non-commercial license.
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import argparse
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import csv
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import json
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import math
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import time
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import numpy as np
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import torch
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import torch.nn.functional as F
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import torch.optim
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import torch.optim as optim
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import torch.utils.data as data
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from nltk.tokenize.treebank import TreebankWordDetokenizer
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from torchtext import data as torchtext_data
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from torchtext import datasets
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from transformers import GPT2Tokenizer, GPT2LMHeadModel
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torch.manual_seed(0)
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np.random.seed(0)
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EPSILON = 1e-10
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device = 'cpu'
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example_sentence = "This is incredible! I love it, this is the best chicken I have ever had."
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max_length_seq = 100
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class ClassificationHead(torch.nn.Module):
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"""Classification Head for transformer encoders"""
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def __init__(self, class_size, embed_size):
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super(ClassificationHead, self).__init__()
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self.class_size = class_size
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self.embed_size = embed_size
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# self.mlp1 = torch.nn.Linear(embed_size, embed_size)
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# self.mlp2 = (torch.nn.Linear(embed_size, class_size))
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self.mlp = torch.nn.Linear(embed_size, class_size)
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def forward(self, hidden_state):
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# hidden_state = F.relu(self.mlp1(hidden_state))
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# hidden_state = self.mlp2(hidden_state)
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logits = self.mlp(hidden_state)
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return logits
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class Discriminator(torch.nn.Module):
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"""Transformer encoder followed by a Classification Head"""
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def __init__(
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self,
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class_size,
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pretrained_model="gpt2-medium",
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cached_mode=False
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):
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super(Discriminator, self).__init__()
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self.tokenizer = GPT2Tokenizer.from_pretrained(pretrained_model)
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self.encoder = GPT2LMHeadModel.from_pretrained(pretrained_model)
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self.embed_size = self.encoder.transformer.config.hidden_size
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self.classifier_head = ClassificationHead(
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class_size=class_size,
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embed_size=self.embed_size
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)
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self.cached_mode = cached_mode
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def get_classifier(self):
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return self.classifier_head
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def train_custom(self):
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for param in self.encoder.parameters():
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param.requires_grad = False
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pass
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self.classifier_head.train()
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def avg_representation(self, x):
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mask = x.ne(0).unsqueeze(2).repeat(
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1, 1, self.embed_size
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).float().to(device).detach()
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hidden, _ = self.encoder.transformer(x)
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masked_hidden = hidden * mask
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avg_hidden = torch.sum(masked_hidden, dim=1) / (
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torch.sum(mask, dim=1).detach() + EPSILON
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)
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return avg_hidden
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def forward(self, x):
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if self.cached_mode:
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avg_hidden = x.to(device)
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else:
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avg_hidden = self.avg_representation(x)
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logits = self.classifier_head(avg_hidden)
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probs = F.log_softmax(logits, dim=-1)
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return probs
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class Dataset(data.Dataset):
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def __init__(self, X, y):
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"""Reads source and target sequences from txt files."""
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self.X = X
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self.y = y
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def __len__(self):
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return len(self.X)
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def __getitem__(self, index):
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"""Returns one data pair (source and target)."""
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data = {}
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data['X'] = self.X[index]
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data['y'] = self.y[index]
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return data
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def collate_fn(data):
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def pad_sequences(sequences):
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lengths = [len(seq) for seq in sequences]
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padded_sequences = torch.zeros(
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len(sequences),
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max(lengths)
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).long() # padding index 0
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for i, seq in enumerate(sequences):
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end = lengths[i]
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padded_sequences[i, :end] = seq[:end]
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return padded_sequences, lengths
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item_info = {}
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for key in data[0].keys():
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item_info[key] = [d[key] for d in data]
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x_batch, _ = pad_sequences(item_info['X'])
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y_batch = torch.tensor(item_info['y'], dtype=torch.long)
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return x_batch, y_batch
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def cached_collate_fn(data):
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item_info = {}
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for key in data[0].keys():
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item_info[key] = [d[key] for d in data]
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x_batch = torch.cat(item_info['X'], 0)
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y_batch = torch.tensor(item_info['y'], dtype=torch.long)
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return x_batch, y_batch
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def train_epoch(data_loader, discriminator, optimizer,
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epoch=0, log_interval=10):
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samples_so_far = 0
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discriminator.train_custom()
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for batch_idx, (input_t, target_t) in enumerate(data_loader):
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input_t, target_t = input_t.to(device), target_t.to(device)
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optimizer.zero_grad()
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output_t = discriminator(input_t)
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loss = F.nll_loss(output_t, target_t)
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loss.backward(retain_graph=True)
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optimizer.step()
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samples_so_far += len(input_t)
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if batch_idx % log_interval == 0:
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print(
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'Train Epoch: {} [{}/{} ({:.0f}%)]\tLoss: {:.6f}'.format(
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epoch + 1,
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samples_so_far, len(data_loader.dataset),
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100 * samples_so_far / len(data_loader.dataset), loss.item()
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)
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)
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def evaluate_performance(data_loader, discriminator):
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discriminator.eval()
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test_loss = 0
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correct = 0
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with torch.no_grad():
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for input_t, target_t in data_loader:
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input_t, target_t = input_t.to(device), target_t.to(device)
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output_t = discriminator(input_t)
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# sum up batch loss
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test_loss += F.nll_loss(output_t, target_t, reduction='sum').item()
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# get the index of the max log-probability
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pred_t = output_t.argmax(dim=1, keepdim=True)
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correct += pred_t.eq(target_t.view_as(pred_t)).sum().item()
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test_loss /= len(data_loader.dataset)
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print(
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'Performance on test set: '
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'Average loss: {:.4f}, Accuracy: {}/{} ({:.0f}%)'.format(
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test_loss, correct, len(data_loader.dataset),
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100. * correct / len(data_loader.dataset)
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)
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)
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def predict(input_sentence, model, classes, cached=False):
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input_t = model.tokenizer.encode(input_sentence)
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input_t = torch.tensor([input_t], dtype=torch.long)
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if cached:
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input_t = model.avg_representation(input_t)
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log_probs = model(input_t).data.cpu().numpy().flatten().tolist()
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print('Input sentence:', input_sentence)
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print('Predictions:', ", ".join(
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"{}: {:.4f}".format(c, math.exp(log_prob)) for c, log_prob in
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zip(classes, log_probs)
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))
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def get_cached_data_loader(dataset, batch_size, discriminator, shuffle=False):
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data_loader = torch.utils.data.DataLoader(dataset=dataset,
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batch_size=batch_size,
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collate_fn=collate_fn)
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xs = []
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ys = []
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for batch_idx, (x, y) in enumerate(data_loader):
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with torch.no_grad():
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x = x.to(device)
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avg_rep = discriminator.avg_representation(x).cpu().detach()
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avg_rep_list = torch.unbind(avg_rep.unsqueeze(1))
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xs += avg_rep_list
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ys += y.cpu().numpy().tolist()
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data_loader = torch.utils.data.DataLoader(
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dataset=Dataset(xs, ys),
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batch_size=batch_size,
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shuffle=shuffle,
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collate_fn=cached_collate_fn)
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return data_loader
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def train_discriminator(
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dataset, dataset_fp=None, pretrained_model='gpt2-medium',
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epochs=10, batch_size=64, log_interval=10,
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save_model=False, cached=False, use_cuda=False):
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if use_cuda:
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global device
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device = 'cuda'
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print('Preprocessing {} dataset...'.format(dataset))
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start = time.time()
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if dataset == 'SST':
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idx2class = ["positive", "negative", "very positive", "very negative",
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"neutral"]
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class2idx = {c: i for i, c in enumerate(idx2class)}
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discriminator = Discriminator(
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class_size=len(idx2class),
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pretrained_model=pretrained_model,
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cached_mode=cached
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).to(device)
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text = torchtext_data.Field()
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label = torchtext_data.Field(sequential=False)
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train_data, val_data, test_data = datasets.SST.splits(
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text,
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label,
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fine_grained=True,
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train_subtrees=True,
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)
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x = []
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y = []
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for i in range(len(train_data)):
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seq = TreebankWordDetokenizer().detokenize(
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vars(train_data[i])["text"]
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)
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seq = discriminator.tokenizer.encode(seq)
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seq = torch.tensor([50256] + seq, device=device, dtype=torch.long)
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x.append(seq)
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y.append(class2idx[vars(train_data[i])["label"]])
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train_dataset = Dataset(x, y)
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test_x = []
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test_y = []
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for i in range(len(test_data)):
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seq = TreebankWordDetokenizer().detokenize(
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vars(test_data[i])["text"]
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)
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seq = discriminator.tokenizer.encode(seq)
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seq = torch.tensor([50256] + seq, device=device, dtype=torch.long)
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test_x.append(seq)
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test_y.append(class2idx[vars(test_data[i])["label"]])
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test_dataset = Dataset(test_x, test_y)
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discriminator_meta = {
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"class_size": len(idx2class),
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"embed_size": discriminator.embed_size,
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"pretrained_model": pretrained_model,
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"class_vocab": class2idx,
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"default_class": 2,
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}
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elif dataset == 'clickbait':
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idx2class = ["non_clickbait", "clickbait"]
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class2idx = {c: i for i, c in enumerate(idx2class)}
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discriminator = Discriminator(
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class_size=len(idx2class),
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pretrained_model=pretrained_model,
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cached_mode=cached
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).to(device)
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with open("datasets/clickbait/clickbait_train_prefix.txt") as f:
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data = []
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for i, line in enumerate(f):
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try:
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data.append(eval(line))
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except:
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print('Error evaluating line {}: {}'.format(
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i, line
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))
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continue
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x = []
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y = []
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y = []
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for i, d in enumerate(data):
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try:
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seq = discriminator.tokenizer.encode(d["text"])
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if len(seq) < max_length_seq:
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seq = torch.tensor(
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[50256] + seq, device=device, dtype=torch.long
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)
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else:
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print("Line {} is longer than maximum length {}".format(
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i, max_length_seq
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))
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continue
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x.append(seq)
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y.append(d['label'])
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except:
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print("Error tokenizing line {}, skipping it".format(i))
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pass
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full_dataset = Dataset(x, y)
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train_size = int(0.9 * len(full_dataset))
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test_size = len(full_dataset) - train_size
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train_dataset, test_dataset = torch.utils.data.random_split(
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full_dataset, [train_size, test_size]
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)
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discriminator_meta = {
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"class_size": len(idx2class),
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"embed_size": discriminator.embed_size,
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"pretrained_model": pretrained_model,
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"class_vocab": class2idx,
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"default_class": 1,
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}
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elif dataset == 'toxic':
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idx2class = ["non_toxic", "toxic"]
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class2idx = {c: i for i, c in enumerate(idx2class)}
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discriminator = Discriminator(
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class_size=len(idx2class),
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pretrained_model=pretrained_model,
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cached_mode=cached
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).to(device)
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with open("datasets/toxic/toxic_train.txt") as f:
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data = []
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for i, line in enumerate(f):
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try:
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data.append(eval(line))
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except:
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print('Error evaluating line {}: {}'.format(
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i, line
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))
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continue
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x = []
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y = []
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for i, d in enumerate(data):
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try:
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seq = discriminator.tokenizer.encode(d["text"])
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if len(seq) < max_length_seq:
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seq = torch.tensor(
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[50256] + seq, device=device, dtype=torch.long
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)
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else:
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print("Line {} is longer than maximum length {}".format(
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i, max_length_seq
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))
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continue
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x.append(seq)
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y.append(int(np.sum(d['label']) > 0))
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except:
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print("Error tokenizing line {}, skipping it".format(i))
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pass
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full_dataset = Dataset(x, y)
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train_size = int(0.9 * len(full_dataset))
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test_size = len(full_dataset) - train_size
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train_dataset, test_dataset = torch.utils.data.random_split(
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full_dataset, [train_size, test_size]
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)
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discriminator_meta = {
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"class_size": len(idx2class),
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"embed_size": discriminator.embed_size,
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"pretrained_model": pretrained_model,
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"class_vocab": class2idx,
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"default_class": 0,
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}
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else: # if dataset == 'generic':
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# This assumes the input dataset is a TSV with the following structure:
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# class \t text
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if dataset_fp is None:
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raise ValueError('When generic dataset is selected, '
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'dataset_fp needs to be specified aswell.')
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classes = set()
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with open(dataset_fp) as f:
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csv_reader = csv.reader(f, delimiter='\t')
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for row in csv_reader:
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classes.add(row[0])
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idx2class = sorted(classes)
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class2idx = {c: i for i, c in enumerate(idx2class)}
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discriminator = Discriminator(
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class_size=len(idx2class),
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pretrained_model=pretrained_model,
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cached_mode=cached
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).to(device)
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x = []
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y = []
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with open(dataset_fp) as f:
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csv_reader = csv.reader(f, delimiter='\t')
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for i, row in enumerate(csv_reader):
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label = row[0]
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text = row[1]
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try:
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seq = discriminator.tokenizer.encode(text)
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if (len(seq) < max_length_seq):
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seq = torch.tensor(
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[50256] + seq,
|
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device=device,
|
||||
dtype=torch.long
|
||||
)
|
||||
|
||||
else:
|
||||
print("Line {} is longer than maximum length {}".format(
|
||||
i, max_length_seq
|
||||
))
|
||||
continue
|
||||
|
||||
x.append(seq)
|
||||
y.append(class2idx[label])
|
||||
|
||||
except:
|
||||
print("Error tokenizing line {}, skipping it".format(i))
|
||||
pass
|
||||
|
||||
full_dataset = Dataset(x, y)
|
||||
train_size = int(0.9 * len(full_dataset))
|
||||
test_size = len(full_dataset) - train_size
|
||||
train_dataset, test_dataset = torch.utils.data.random_split(
|
||||
full_dataset,
|
||||
[train_size, test_size]
|
||||
)
|
||||
|
||||
discriminator_meta = {
|
||||
"class_size": len(idx2class),
|
||||
"embed_size": discriminator.embed_size,
|
||||
"pretrained_model": pretrained_model,
|
||||
"class_vocab": class2idx,
|
||||
"default_class": 0,
|
||||
}
|
||||
|
||||
end = time.time()
|
||||
print('Preprocessed {} data points'.format(
|
||||
len(train_dataset) + len(test_dataset))
|
||||
)
|
||||
print("Data preprocessing took: {:.3f}s".format(end - start))
|
||||
|
||||
if cached:
|
||||
start = time.time()
|
||||
|
||||
train_loader = get_cached_data_loader(
|
||||
train_dataset, batch_size, discriminator, shuffle=True
|
||||
)
|
||||
|
||||
test_loader = get_cached_data_loader(
|
||||
test_dataset, batch_size, discriminator
|
||||
)
|
||||
|
||||
end = time.time()
|
||||
print("Building representation cache took: {:.3f}s".format(end - start))
|
||||
|
||||
else:
|
||||
train_loader = torch.utils.data.DataLoader(dataset=train_dataset,
|
||||
batch_size=batch_size,
|
||||
shuffle=True,
|
||||
collate_fn=collate_fn)
|
||||
test_loader = torch.utils.data.DataLoader(dataset=test_dataset,
|
||||
batch_size=batch_size,
|
||||
collate_fn=collate_fn)
|
||||
|
||||
if save_model:
|
||||
with open("{}_classifier_head_meta.json".format(dataset),
|
||||
"w") as meta_file:
|
||||
json.dump(discriminator_meta, meta_file)
|
||||
|
||||
optimizer = optim.Adam(discriminator.parameters(), lr=0.0001)
|
||||
|
||||
for epoch in range(epochs):
|
||||
start = time.time()
|
||||
print('\nEpoch', epoch + 1)
|
||||
|
||||
train_epoch(
|
||||
discriminator=discriminator,
|
||||
data_loader=train_loader,
|
||||
optimizer=optimizer,
|
||||
epoch=epoch,
|
||||
log_interval=log_interval
|
||||
)
|
||||
evaluate_performance(
|
||||
data_loader=test_loader,
|
||||
discriminator=discriminator
|
||||
)
|
||||
|
||||
end = time.time()
|
||||
print("Epoch took: {:.3f}s".format(end - start))
|
||||
|
||||
print("\nExample prediction")
|
||||
predict(example_sentence, discriminator, idx2class, cached)
|
||||
|
||||
if save_model:
|
||||
# torch.save(discriminator.state_dict(),
|
||||
# "{}_discriminator_{}.pt".format(
|
||||
# args.dataset, epoch
|
||||
# ))
|
||||
torch.save(discriminator.get_classifier().state_dict(),
|
||||
"{}_classifier_head_epoch_{}.pt".format(dataset, epoch))
|
||||
|
||||
|
||||
if __name__ == '__main__':
|
||||
parser = argparse.ArgumentParser(
|
||||
description='Train a discriminator on top of GPT-2 representations')
|
||||
parser.add_argument('--dataset', type=str, default='SST',
|
||||
choices=('SST', 'clickbait', 'toxic', 'generic'),
|
||||
help='dataset to train the discriminator on.'
|
||||
'In case of generic, the dataset is expected'
|
||||
'to be a TSBV file with structure: class \\t text')
|
||||
parser.add_argument('--dataset_fp', type=str, default='',
|
||||
help='File path of the dataset to use. '
|
||||
'Needed only in case of generic datadset')
|
||||
parser.add_argument('--pretrained_model', type=str, default='gpt2-medium',
|
||||
help='Pretrained model to use as encoder')
|
||||
parser.add_argument('--epochs', type=int, default=10, metavar='N',
|
||||
help='Number of training epochs')
|
||||
parser.add_argument('--batch_size', type=int, default=64, metavar='N',
|
||||
help='input batch size for training (default: 64)')
|
||||
parser.add_argument('--log_interval', type=int, default=10, metavar='N',
|
||||
help='how many batches to wait before logging training status')
|
||||
parser.add_argument('--save_model', action='store_true',
|
||||
help='whether to save the model')
|
||||
parser.add_argument('--cached', action='store_true',
|
||||
help='whether to cache the input representations')
|
||||
parser.add_argument('--use_cuda', action='store_true',
|
||||
help='use to turn on cuda')
|
||||
args = parser.parse_args()
|
||||
|
||||
train_discriminator(**(vars(args)))
|
Loading…
Reference in New Issue