748 lines
23 KiB
Python
748 lines
23 KiB
Python
from argparse import Namespace
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from collections import Counter
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import json
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import os
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import re
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import string
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import numpy as np
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import pandas as pd
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import torch
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import torch.nn as nn
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import torch.nn.functional as F
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import torch.optim as optim
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from torch.utils.data import Dataset, DataLoader
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from tqdm.notebook import tqdm
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class Vocabulary(object):
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"""Class to process text and extract vocabulary for mapping"""
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def __init__(self, token_to_idx=None, add_unk=True, unk_token="<UNK>"):
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"""
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Args:
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token_to_idx (dict): a pre-existing map of tokens to indices
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add_unk (bool): a flag that indicates whether to add the UNK token
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unk_token (str): the UNK token to add into the Vocabulary
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"""
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if token_to_idx is None:
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token_to_idx = {}
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self._token_to_idx = token_to_idx
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self._idx_to_token = {idx: token
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for token, idx in self._token_to_idx.items()}
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self._add_unk = add_unk
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self._unk_token = unk_token
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self.unk_index = -1
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if add_unk:
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self.unk_index = self.add_token(unk_token)
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def to_serializable(self):
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""" returns a dictionary that can be serialized """
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return {'token_to_idx': self._token_to_idx,
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'add_unk': self._add_unk,
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'unk_token': self._unk_token}
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@classmethod
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def from_serializable(cls, contents):
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""" instantiates the Vocabulary from a serialized dictionary """
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return cls(**contents)
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def add_token(self, token):
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"""Update mapping dicts based on the token.
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Args:
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token (str): the item to add into the Vocabulary
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Returns:
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index (int): the integer corresponding to the token
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"""
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if token in self._token_to_idx:
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index = self._token_to_idx[token]
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else:
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index = len(self._token_to_idx)
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self._token_to_idx[token] = index
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self._idx_to_token[index] = token
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return index
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def add_many(self, tokens):
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"""Add a list of tokens into the Vocabulary
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Args:
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tokens (list): a list of string tokens
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Returns:
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indices (list): a list of indices corresponding to the tokens
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"""
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return [self.add_token(token) for token in tokens]
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def lookup_token(self, token):
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"""Retrieve the index associated with the token
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or the UNK index if token isn't present.
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Args:
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token (str): the token to look up
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Returns:
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index (int): the index corresponding to the token
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Notes:
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`unk_index` needs to be >=0 (having been added into the Vocabulary)
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for the UNK functionality
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"""
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if self.unk_index >= 0:
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return self._token_to_idx.get(token, self.unk_index)
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else:
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return self._token_to_idx[token]
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def lookup_index(self, index):
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"""Return the token associated with the index
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Args:
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index (int): the index to look up
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Returns:
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token (str): the token corresponding to the index
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Raises:
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KeyError: if the index is not in the Vocabulary
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"""
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if index not in self._idx_to_token:
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raise KeyError("the index (%d) is not in the Vocabulary" % index)
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return self._idx_to_token[index]
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def __str__(self):
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return "<Vocabulary(size=%d)>" % len(self)
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def __len__(self):
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return len(self._token_to_idx)
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class ReviewVectorizer(object):
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""" The Vectorizer which coordinates the Vocabularies and puts them to use"""
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def __init__(self, review_vocab, rating_vocab):
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"""
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Args:
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review_vocab (Vocabulary): maps words to integers
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rating_vocab (Vocabulary): maps class labels to integers
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"""
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self.review_vocab = review_vocab
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self.rating_vocab = rating_vocab
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def vectorize(self, review):
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"""Create a collapsed one-hit vector for the review
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Args:
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review (str): the review
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Returns:
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one_hot (np.ndarray): the collapsed one-hot encoding
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"""
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one_hot = np.zeros(len(self.review_vocab), dtype=np.float32)
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for token in review.split(" "):
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if token not in string.punctuation:
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one_hot[self.review_vocab.lookup_token(token)] = 1
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return one_hot
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@classmethod
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def from_dataframe(cls, review_df, cutoff=25):
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"""Instantiate the vectorizer from the dataset dataframe
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Args:
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review_df (pandas.DataFrame): the review dataset
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cutoff (int): the parameter for frequency-based filtering
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Returns:
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an instance of the ReviewVectorizer
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"""
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review_vocab = Vocabulary(add_unk=True)
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rating_vocab = Vocabulary(add_unk=False)
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# Add ratings
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for rating in sorted(set(review_df.rating)):
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rating_vocab.add_token(rating)
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# Add top words if count > provided count
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word_counts = Counter()
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for review in review_df.review:
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for word in review.split(" "):
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if word not in string.punctuation:
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word_counts[word] += 1
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for word, count in word_counts.items():
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if count > cutoff:
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review_vocab.add_token(word)
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return cls(review_vocab, rating_vocab)
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@classmethod
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def from_serializable(cls, contents):
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"""Instantiate a ReviewVectorizer from a serializable dictionary
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Args:
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contents (dict): the serializable dictionary
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Returns:
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an instance of the ReviewVectorizer class
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"""
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review_vocab = Vocabulary.from_serializable(contents['review_vocab'])
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rating_vocab = Vocabulary.from_serializable(contents['rating_vocab'])
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return cls(review_vocab=review_vocab, rating_vocab=rating_vocab)
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def to_serializable(self):
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"""Create the serializable dictionary for caching
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Returns:
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contents (dict): the serializable dictionary
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"""
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return {'review_vocab': self.review_vocab.to_serializable(),
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'rating_vocab': self.rating_vocab.to_serializable()}
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class ReviewDataset(Dataset):
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def __init__(self, review_df, vectorizer):
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"""
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Args:
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review_df (pandas.DataFrame): the dataset
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vectorizer (ReviewVectorizer): vectorizer instantiated from dataset
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"""
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self.review_df = review_df
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self._vectorizer = vectorizer
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self.train_df = self.review_df[self.review_df.split=='train']
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self.train_size = len(self.train_df)
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self.val_df = self.review_df[self.review_df.split=='val']
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self.validation_size = len(self.val_df)
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self.test_df = self.review_df[self.review_df.split=='test']
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self.test_size = len(self.test_df)
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self._lookup_dict = {'train': (self.train_df, self.train_size),
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'val': (self.val_df, self.validation_size),
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'test': (self.test_df, self.test_size)}
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self.set_split('train')
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@classmethod
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def load_dataset_and_make_vectorizer(cls, review_csv):
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"""Load dataset and make a new vectorizer from scratch
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Args:
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review_csv (str): location of the dataset
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Returns:
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an instance of ReviewDataset
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"""
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review_df = pd.read_csv(review_csv)
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train_review_df = review_df[review_df.split=='train']
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return cls(review_df, ReviewVectorizer.from_dataframe(train_review_df))
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@classmethod
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def load_dataset_and_load_vectorizer(cls, review_csv, vectorizer_filepath):
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"""Load dataset and the corresponding vectorizer.
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Used in the case in the vectorizer has been cached for re-use
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Args:
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review_csv (str): location of the dataset
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vectorizer_filepath (str): location of the saved vectorizer
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Returns:
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an instance of ReviewDataset
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"""
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review_df = pd.read_csv(review_csv)
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vectorizer = cls.load_vectorizer_only(vectorizer_filepath)
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return cls(review_df, vectorizer)
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@staticmethod
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def load_vectorizer_only(vectorizer_filepath):
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"""a static method for loading the vectorizer from file
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Args:
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vectorizer_filepath (str): the location of the serialized vectorizer
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Returns:
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an instance of ReviewVectorizer
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"""
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with open(vectorizer_filepath) as fp:
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return ReviewVectorizer.from_serializable(json.load(fp))
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def save_vectorizer(self, vectorizer_filepath):
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"""saves the vectorizer to disk using json
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Args:
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vectorizer_filepath (str): the location to save the vectorizer
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"""
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with open(vectorizer_filepath, "w") as fp:
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json.dump(self._vectorizer.to_serializable(), fp)
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def get_vectorizer(self):
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""" returns the vectorizer """
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return self._vectorizer
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def set_split(self, split="train"):
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""" selects the splits in the dataset using a column in the dataframe
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Args:
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split (str): one of "train", "val", or "test"
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"""
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self._target_split = split
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self._target_df, self._target_size = self._lookup_dict[split]
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def __len__(self):
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return self._target_size
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def __getitem__(self, index):
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"""the primary entry point method for PyTorch datasets
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Args:
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index (int): the index to the data point
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Returns:
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a dictionary holding the data point's features (x_data) and label (y_target)
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"""
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row = self._target_df.iloc[index]
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review_vector = \
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self._vectorizer.vectorize(row.review)
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rating_index = \
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self._vectorizer.rating_vocab.lookup_token(row.rating)
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return {'x_data': review_vector,
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'y_target': rating_index}
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def get_num_batches(self, batch_size):
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"""Given a batch size, return the number of batches in the dataset
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Args:
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batch_size (int)
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Returns:
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number of batches in the dataset
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"""
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return len(self) // batch_size
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def generate_batches(dataset, batch_size, shuffle=True,
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drop_last=True, device="cpu"):
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"""
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A generator function which wraps the PyTorch DataLoader. It will
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ensure each tensor is on the write device location.
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"""
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dataloader = DataLoader(dataset=dataset, batch_size=batch_size,
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shuffle=shuffle, drop_last=drop_last)
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for data_dict in dataloader:
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out_data_dict = {}
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for name, tensor in data_dict.items():
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out_data_dict[name] = data_dict[name].to(device)
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yield out_data_dict
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class ReviewClassifier(nn.Module):
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""" a simple perceptron based classifier """
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def __init__(self, num_features):
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"""
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Args:
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num_features (int): the size of the input feature vector
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"""
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super(ReviewClassifier, self).__init__()
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self.fc1 = nn.Linear(in_features=num_features,
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out_features=1)
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def forward(self, x_in, apply_sigmoid=False):
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"""The forward pass of the classifier
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Args:
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x_in (torch.Tensor): an input data tensor.
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x_in.shape should be (batch, num_features)
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apply_sigmoid (bool): a flag for the sigmoid activation
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should be false if used with the Cross Entropy losses
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Returns:
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the resulting tensor. tensor.shape should be (batch,)
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"""
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y_out = self.fc1(x_in).squeeze()
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if apply_sigmoid:
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y_out = torch.sigmoid(y_out)
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return y_out
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def make_train_state(args):
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return {'stop_early': False,
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'early_stopping_step': 0,
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'early_stopping_best_val': 1e8,
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'learning_rate': args.learning_rate,
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'epoch_index': 0,
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'train_loss': [],
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'train_acc': [],
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'val_loss': [],
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'val_acc': [],
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'test_loss': -1,
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'test_acc': -1,
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'model_filename': args.model_state_file}
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def update_train_state(args, model, train_state):
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"""Handle the training state updates.
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Components:
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- Early Stopping: Prevent overfitting.
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- Model Checkpoint: Model is saved if the model is better
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:param args: main arguments
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:param model: model to train
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:param train_state: a dictionary representing the training state values
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:returns:
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a new train_state
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"""
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# Save one model at least
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if train_state['epoch_index'] == 0:
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torch.save(model.state_dict(), train_state['model_filename'])
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train_state['stop_early'] = False
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# Save model if performance improved
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elif train_state['epoch_index'] >= 1:
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loss_tm1, loss_t = train_state['val_loss'][-2:]
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# If loss worsened
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if loss_t >= train_state['early_stopping_best_val']:
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# Update step
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train_state['early_stopping_step'] += 1
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# Loss decreased
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else:
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# Save the best model
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if loss_t < train_state['early_stopping_best_val']:
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torch.save(model.state_dict(), train_state['model_filename'])
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# Reset early stopping step
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train_state['early_stopping_step'] = 0
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# Stop early ?
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train_state['stop_early'] = \
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train_state['early_stopping_step'] >= args.early_stopping_criteria
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return train_state
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def compute_accuracy(y_pred, y_target):
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y_target = y_target.cpu()
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y_pred_indices = (torch.sigmoid(y_pred)>0.5).cpu().long()#.max(dim=1)[1]
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n_correct = torch.eq(y_pred_indices, y_target).sum().item()
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return n_correct / len(y_pred_indices) * 100
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def set_seed_everywhere(seed, cuda):
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np.random.seed(seed)
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torch.manual_seed(seed)
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if cuda:
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torch.cuda.manual_seed_all(seed)
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def handle_dirs(dirpath):
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if not os.path.exists(dirpath):
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os.makedirs(dirpath)
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args = Namespace(
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# Data and Path information
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frequency_cutoff=25,
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model_state_file='model.pth',
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review_csv='data/yelp/reviews_with_splits_lite.csv',
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# review_csv='data/yelp/reviews_with_splits_full.csv',
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save_dir='model_storage/ch3/yelp/',
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vectorizer_file='vectorizer.json',
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# No Model hyper parameters
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# Training hyper parameters
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batch_size=128,
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early_stopping_criteria=5,
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learning_rate=0.001,
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num_epochs=100,
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seed=1337,
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# Runtime options
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catch_keyboard_interrupt=True,
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cuda=True,
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expand_filepaths_to_save_dir=True,
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reload_from_files=False,
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)
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if args.expand_filepaths_to_save_dir:
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args.vectorizer_file = os.path.join(args.save_dir,
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args.vectorizer_file)
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args.model_state_file = os.path.join(args.save_dir,
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args.model_state_file)
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print("Expanded filepaths: ")
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print("\t{}".format(args.vectorizer_file))
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print("\t{}".format(args.model_state_file))
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# Check CUDA
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if not torch.cuda.is_available():
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args.cuda = False
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if torch.cuda.device_count() > 1:
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print("Pouzivam", torch.cuda.device_count(), "graficke karty!")
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args.device = torch.device("cuda" if args.cuda else "cpu")
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# Set seed for reproducibility
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set_seed_everywhere(args.seed, args.cuda)
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# handle dirs
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handle_dirs(args.save_dir)
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if args.reload_from_files:
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# training from a checkpoint
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print("Loading dataset and vectorizer")
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dataset = ReviewDataset.load_dataset_and_load_vectorizer(args.review_csv,
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args.vectorizer_file)
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else:
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print("Loading dataset and creating vectorizer")
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# create dataset and vectorizer
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dataset = ReviewDataset.load_dataset_and_make_vectorizer(args.review_csv)
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dataset.save_vectorizer(args.vectorizer_file)
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vectorizer = dataset.get_vectorizer()
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classifier = ReviewClassifier(num_features=len(vectorizer.review_vocab))
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classifier = nn.DataParallel(classifier)
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classifier = classifier.to(args.device)
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loss_func = nn.BCEWithLogitsLoss()
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optimizer = optim.Adam(classifier.parameters(), lr=args.learning_rate)
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scheduler = optim.lr_scheduler.ReduceLROnPlateau(optimizer=optimizer,
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mode='min', factor=0.5,
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patience=1)
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train_state = make_train_state(args)
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epoch_bar = tqdm(desc='training routine',
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total=args.num_epochs,
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position=0)
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dataset.set_split('train')
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train_bar = tqdm(desc='split=train',
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total=dataset.get_num_batches(args.batch_size),
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position=1,
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leave=True)
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dataset.set_split('val')
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val_bar = tqdm(desc='split=val',
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total=dataset.get_num_batches(args.batch_size),
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position=1,
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leave=True)
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try:
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for epoch_index in range(args.num_epochs):
|
|
train_state['epoch_index'] = epoch_index
|
|
|
|
# Iterate over training dataset
|
|
|
|
# setup: batch generator, set loss and acc to 0, set train mode on
|
|
dataset.set_split('train')
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|
batch_generator = generate_batches(dataset,
|
|
batch_size=args.batch_size,
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|
device=args.device)
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|
running_loss = 0.0
|
|
running_acc = 0.0
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|
classifier.train()
|
|
|
|
for batch_index, batch_dict in enumerate(batch_generator):
|
|
# the training routine is these 5 steps:
|
|
|
|
# --------------------------------------
|
|
# step 1. zero the gradients
|
|
optimizer.zero_grad()
|
|
|
|
# step 2. compute the output
|
|
y_pred = classifier(x_in=batch_dict['x_data'].float())
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|
|
|
# step 3. compute the loss
|
|
loss = loss_func(y_pred, batch_dict['y_target'].float())
|
|
loss_t = loss.item()
|
|
running_loss += (loss_t - running_loss) / (batch_index + 1)
|
|
|
|
# step 4. use loss to produce gradients
|
|
loss.backward()
|
|
|
|
# step 5. use optimizer to take gradient step
|
|
optimizer.step()
|
|
# -----------------------------------------
|
|
# compute the accuracy
|
|
acc_t = compute_accuracy(y_pred, batch_dict['y_target'])
|
|
running_acc += (acc_t - running_acc) / (batch_index + 1)
|
|
|
|
# update bar
|
|
train_bar.set_postfix(loss=running_loss,
|
|
acc=running_acc,
|
|
epoch=epoch_index)
|
|
train_bar.update()
|
|
|
|
train_state['train_loss'].append(running_loss)
|
|
train_state['train_acc'].append(running_acc)
|
|
|
|
# Iterate over val dataset
|
|
|
|
# setup: batch generator, set loss and acc to 0; set eval mode on
|
|
dataset.set_split('val')
|
|
batch_generator = generate_batches(dataset,
|
|
batch_size=args.batch_size,
|
|
device=args.device)
|
|
running_loss = 0.
|
|
running_acc = 0.
|
|
classifier.eval()
|
|
|
|
for batch_index, batch_dict in enumerate(batch_generator):
|
|
|
|
# compute the output
|
|
y_pred = classifier(x_in=batch_dict['x_data'].float())
|
|
|
|
# step 3. compute the loss
|
|
loss = loss_func(y_pred, batch_dict['y_target'].float())
|
|
loss_t = loss.item()
|
|
running_loss += (loss_t - running_loss) / (batch_index + 1)
|
|
|
|
# compute the accuracy
|
|
acc_t = compute_accuracy(y_pred, batch_dict['y_target'])
|
|
running_acc += (acc_t - running_acc) / (batch_index + 1)
|
|
|
|
val_bar.set_postfix(loss=running_loss,
|
|
acc=running_acc,
|
|
epoch=epoch_index)
|
|
val_bar.update()
|
|
|
|
train_state['val_loss'].append(running_loss)
|
|
train_state['val_acc'].append(running_acc)
|
|
|
|
train_state = update_train_state(args=args, model=classifier,
|
|
train_state=train_state)
|
|
|
|
scheduler.step(train_state['val_loss'][-1])
|
|
|
|
train_bar.n = 0
|
|
val_bar.n = 0
|
|
epoch_bar.update()
|
|
|
|
if train_state['stop_early']:
|
|
break
|
|
|
|
train_bar.n = 0
|
|
val_bar.n = 0
|
|
epoch_bar.update()
|
|
except KeyboardInterrupt:
|
|
print("Exiting loop")
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
classifier.load_state_dict(torch.load(train_state['model_filename']))
|
|
classifier = classifier.to(args.device)
|
|
|
|
dataset.set_split('test')
|
|
batch_generator = generate_batches(dataset,
|
|
batch_size=args.batch_size,
|
|
device=args.device)
|
|
running_loss = 0.
|
|
running_acc = 0.
|
|
classifier.eval()
|
|
|
|
for batch_index, batch_dict in enumerate(batch_generator):
|
|
# compute the output
|
|
y_pred = classifier(x_in=batch_dict['x_data'].float())
|
|
|
|
# compute the loss
|
|
loss = loss_func(y_pred, batch_dict['y_target'].float())
|
|
loss_t = loss.item()
|
|
running_loss += (loss_t - running_loss) / (batch_index + 1)
|
|
|
|
# compute the accuracy
|
|
acc_t = compute_accuracy(y_pred, batch_dict['y_target'])
|
|
running_acc += (acc_t - running_acc) / (batch_index + 1)
|
|
|
|
train_state['test_loss'] = running_loss
|
|
train_state['test_acc'] = running_acc
|
|
|
|
|
|
|
|
|
|
|
|
|
|
print("Test loss: {:.3f}".format(train_state['test_loss']))
|
|
print("Test Accuracy: {:.2f}".format(train_state['test_acc']))
|
|
|
|
|
|
|
|
|
|
|
|
|
|
def preprocess_text(text):
|
|
text = text.lower()
|
|
text = re.sub(r"([.,!?])", r" \1 ", text)
|
|
text = re.sub(r"[^a-zA-Z.,!?]+", r" ", text)
|
|
return text
|
|
|
|
|
|
|
|
|
|
|
|
def predict_rating(review, classifier, vectorizer, decision_threshold=0.5):
|
|
"""Predict the rating of a review
|
|
|
|
Args:
|
|
review (str): the text of the review
|
|
classifier (ReviewClassifier): the trained model
|
|
vectorizer (ReviewVectorizer): the corresponding vectorizer
|
|
decision_threshold (float): The numerical boundary which separates the rating classes
|
|
"""
|
|
review = preprocess_text(review)
|
|
|
|
vectorized_review = torch.tensor(vectorizer.vectorize(review))
|
|
result = classifier(vectorized_review.view(1, -1))
|
|
|
|
probability_value = F.sigmoid(result).item()
|
|
index = 1
|
|
if probability_value < decision_threshold:
|
|
index = 0
|
|
|
|
return vectorizer.rating_vocab.lookup_index(index)
|
|
|
|
|
|
|
|
|
|
|
|
test_review = "this is a pretty awesome book"
|
|
|
|
classifier = classifier.cpu()
|
|
prediction = predict_rating(test_review, classifier, vectorizer, decision_threshold=0.5)
|
|
print("{} -> {}".format(test_review, prediction))
|
|
|
|
|
|
|
|
|
|
|
|
# Sort weights
|
|
fc1_weights = classifier.fc1.weight.detach()[0]
|
|
_, indices = torch.sort(fc1_weights, dim=0, descending=True)
|
|
indices = indices.numpy().tolist()
|
|
|
|
# Top 20 words
|
|
print("Influential words in Positive Reviews:")
|
|
print("--------------------------------------")
|
|
for i in range(20):
|
|
print(vectorizer.review_vocab.lookup_index(indices[i]))
|
|
|
|
print("====\n\n\n")
|
|
|
|
# Top 20 negative words
|
|
print("Influential words in Negative Reviews:")
|
|
print("--------------------------------------")
|
|
indices.reverse()
|
|
for i in range(20):
|
|
print(vectorizer.review_vocab.lookup_index(indices[i])) |