Minor eval changes

ADA/server/agent/dataloader.py

@@ -2,7 +2,7 @@ import pandas as pd
 
 
 class DataLoader:
-    data_location = 'agent/amazon_data/reviews_for_backpack.tsv'
+    data_location = 'agent/amazon_data/reviews_for_watches.tsv'
     reviews = pd.read_csv(data_location, sep='\t', error_bad_lines=False)
 
     def get_reviews(self, product_id):

ADA/server/agent/prep_metadata.py

 import pandas as pd
-import gzip
-import json
-
-MAX_ITEMS = 200000
-
-
-def parse(path):
-    g = gzip.open(path, 'rb')
-    for line in g:
-        yield json.loads(line)
-
-
-def get_df(path):
-    i = 0
-    df = {}
-    for d in parse(path):
-        df[i] = d
-        i += 1
-        if i == MAX_ITEMS:
-            break
-    return pd.DataFrame.from_dict(df, orient='index')
-
 
 pd.set_option('display.max_colwidth', None)
 
-category = 'Cardigans'
 
-metadata_iter = pd.read_json('amazon_data/meta_Clothing_Shoes_and_Jewelry.json', lines=True, chunksize=1000)
-metadata = pd.concat([metadata[metadata['category'].apply(lambda cl: type(cl) is list and category in cl)]
-                      for metadata in metadata_iter])
+def get_reviews(category, meta_file, review_file):
+    metadata_iter = pd.read_json(meta_file, lines=True, chunksize=1000)
+    metadata = pd.concat([metadata[metadata['category'].apply(lambda cl: type(cl) is list and category in cl)]
+                          for metadata in metadata_iter])
+    print(len(metadata.index))
 
-print(len(metadata.index))
+    review_iter = pd.read_json(review_file, lines=True, chunksize=1000)
+    reviews = pd.concat([reviews[reviews['asin'].isin(metadata['asin'])] for reviews in review_iter])
+    print(len(reviews.index))
 
-review_iter = pd.read_json('amazon_data/Clothing_Shoes_and_Jewelry.json', lines=True, chunksize=1000)
-reviews = pd.concat([reviews[reviews['asin'].isin(metadata['asin'])] for reviews in review_iter])
+    return reviews
 
-print(len(reviews.index))
 
-reviews.to_csv('target_extraction/data/verified_cardigan_reviews.tsv', sep='\t', index=False)
+def save_reviews(category, meta_file, review_file, output_file):
+    reviews = get_reviews(category, meta_file, review_file)
+    reviews.to_csv(output_file, sep='\t', index=False)
 
-# child_product = 'speaker'
-# reviews = pd.read_csv('amazon_data/amazon_reviews_us_Electronics_v1_00.tsv.gz', sep='\t', error_bad_lines=False,
-#                       compression='gzip')
-# parent_output = 'target_extraction/data/electronics_reviews.tsv'
-# child_output = 'target_extraction/data/' + child_product + '_reviews.tsv'
-#
-# for col in reviews.columns:
-#     print(col)
-#
-# c_reviews = reviews[reviews['product_title'].str.contains(child_product, case=False, na=False)]
-# p_reviews = reviews[~reviews['product_title'].str.contains(child_product, case=False, na=False)]
-# c_reviews = c_reviews.sample(frac=1).reset_index(drop=True)
-# c_reviews = c_reviews.head(MAX_ITEMS)
-# p_reviews = p_reviews.sample(frac=1).reset_index(drop=True)
-# p_reviews = p_reviews.head(MAX_ITEMS)
-#
-# p_reviews.to_csv(parent_output, sep='\t', index=False)
-# c_reviews.to_csv(child_output, sep='\t', index=False)
-# print('Successfully prepared data for', len(p_reviews.index), 'parent and', len(c_reviews.index), 'child reviews')
 
-# # get metadata for sunglasses
-# metadata = metadata[metadata['title'].str.contains(pat='[G]uitar', na=False, regex=True)]
+def save_top_reviewed_products(n, category, meta_file, review_file, output_file, product_title):
+    reviews = get_reviews(category, meta_file, review_file)
+    top_reviewed = reviews.groupby(['asin'], sort=False).size().sort_values(ascending=False).head(n)
+    reviews = reviews[reviews['asin'].apply(lambda asin: asin in top_reviewed)]
+    reviews = reviews.rename(columns={'overall': 'star_rating', 'asin': 'product_id', 'reviewerID': 'review_id',
+                                      'reviewText': 'review_body'})
+    reviews = reviews[reviews['review_body'].apply(lambda b: b is not None and len(b) > 0)]
+    reviews = reviews[reviews['star_rating'].apply(lambda r: type(r) is int or r.isdigit())]
+    reviews['product_title'] = product_title
+    reviews.to_csv(output_file, sep='\t', index=False)
 
-# # get metadata for camera products
-# metadata = metadata[metadata['main_cat'] == 'Camera & Photo']
-#
-# # try to filter out camera accessories
-# filter_words = ['accessor', 'battery', 'charger', 'tripod', 'strap', 'case', 'bag', 'book', 'filter', 'light', 'drive',
-#                 'backpack', 'kit', 'printer', 'adapter', 'album', 'surveillance', 'security', 'cctv', 'cassette']
-# filter_pat = ''
-# for word in filter_words:
-#     word_filter = '[' + word[0].upper() + word[0].lower() + ']' + word[1:]
-#     filter_pat += word_filter + '|'
-# filter_pat = filter_pat[:-1]
-# r = re.compile(filter_pat)
-# metadata = metadata[~metadata['title'].str.contains(pat=filter_pat, na=False, regex=True)]
-# metadata = metadata[~metadata['category'].apply(lambda cats: any(r.search(cat) for cat in cats))]
-#
-# for _, row in metadata.head(20).iterrows():
-#     print('features:', row['feature'])
-#     print('description:', row['description'])
-#     print('tech1:', row['tech1'])
-#     print('tech2:', row['tech2'])
 
+# save_top_reviewed_products(3, 'Wrist Watches', 'amazon_data/meta_Clothing_Shoes_and_Jewelry.json',
+#                            'amazon_data/Clothing_Shoes_and_Jewelry.json', 'amazon_data/reviews_for_watches.tsv',
+#                            'watch')
 
+save_reviews('Necklaces', 'agent/amazon_data/meta_Clothing_Shoes_and_Jewelry.json', 'agent/amazon_data/Clothing_Shoes_and_Jewelry.json', 'agent/target_extraction/data/verified_necklace_reviews.tsv')

ADA/server/agent/target_extraction/BERT/entity_extractor/bert_entity_extractor.py

@@ -20,7 +20,7 @@ LEARNING_RATE = 0.00002
 MAX_GRAD_NORM = 1.0
 
 # training
-N_EPOCHS = 2
+N_EPOCHS = 3
 BATCH_SIZE = 32
 WARM_UP_FRAC = 0.05
 
@@ -48,13 +48,13 @@ class BertEntityExtractor:
         return extractor
 
     @staticmethod
-    def train_and_validate(file_path, save_path, size=None, valid_frac=None, valid_file_path=None):
+    def train_and_validate(file_path, save_file, size=None, valid_frac=None, valid_file_path=None):
         extractor = BertEntityExtractor()
-        extractor.train_with_file(file_path, save_path, size=size, valid_frac=valid_frac,
+        extractor.train_with_file(file_path, save_file, size=size, valid_frac=valid_frac,
                                   valid_file_path=valid_file_path)
         return extractor
 
-    def train_with_file(self, file_path, save_path, size=None, valid_frac=None, valid_file_path=None):
+    def train_with_file(self, file_path, save_file, size=None, valid_frac=None, valid_file_path=None):
         # load training data
         if valid_file_path is None:
             train_data, valid_data = EntityDataset.from_file(file_path, size=size, valid_frac=valid_frac)
@@ -122,11 +122,11 @@ class BertEntityExtractor:
             if valid_data is not None:
                 self.evaluate(data=valid_data)
 
+        torch.save(self.net.state_dict(), '{}.pt'.format(save_file))
+
         end = time.time()
         print('Training took', end - start, 'seconds')
 
-        torch.save(self.net.state_dict(), save_path)
-
     def evaluate(self, file_path=None, data=None, size=None):
         # load eval data
         if file_path is not None:

ADA/server/agent/target_extraction/BERT/relation_extractor/bert_rel_extractor.py

@@ -19,7 +19,7 @@ LEARNING_RATE = 0.00002
 MAX_GRAD_NORM = 1.0
 
 # training
-N_EPOCHS = 2
+N_EPOCHS = 3
 BATCH_SIZE = 16
 WARM_UP_FRAC = 0.05
 
@@ -47,13 +47,13 @@ class BertRelExtractor:
         return extractor
 
     @staticmethod
-    def train_and_validate(file_path, save_path, size=None, valid_frac=None, valid_file_path=None):
+    def train_and_validate(file_path, save_file, size=None, valid_frac=None, valid_file_path=None):
         extractor = BertRelExtractor()
-        extractor.train_with_file(file_path, save_path, size=size, valid_frac=valid_frac,
+        extractor.train_with_file(file_path, save_file, size=size, valid_frac=valid_frac,
                                   valid_file_path=valid_file_path)
         return extractor
 
-    def train_with_file(self, file_path, save_path, size=None, valid_frac=None, valid_file_path=None):
+    def train_with_file(self, file_path, save_file, size=None, valid_frac=None, valid_file_path=None):
         # load training data
         if valid_file_path is None:
             train_data, valid_data = PairRelDataset.from_file(file_path, size=size, valid_frac=valid_frac)
@@ -121,11 +121,11 @@ class BertRelExtractor:
             if valid_data is not None:
                 self.evaluate(data=valid_data)
 
+        torch.save(self.net.state_dict(), '{}.pt'.format(save_file))
+
         end = time.time()
         print('Training took', end - start, 'seconds')
 
-        torch.save(self.net.state_dict(), save_path)
-
     def evaluate(self, file_path=None, data=None, size=None):
         # load eval data
         if file_path is not None:

ADA/server/agent/target_extraction/BERT/relation_extractor/pair_rel_dataset.py

@@ -5,6 +5,7 @@ import pandas as pd
 import numpy as np
 from ast import literal_eval
 from agent.target_extraction.BERT.relation_extractor.pairbertnet import TRAINED_WEIGHTS, HIDDEN_OUTPUT_FEATURES
+import os
 
 MAX_SEQ_LEN = 128
 RELATIONS = ['/has_feature', '/no_relation']
@@ -69,11 +70,12 @@ class PairRelDataset(Dataset):
         return dataset
 
     @staticmethod
-    def from_file(path, valid_frac=None, size=None):
-        if path.endswith('.json'):
-            dataset = PairRelDataset(pd.read_json(path, lines=True), size=size)
-        elif path.endswith('.tsv'):
-            dataset = PairRelDataset(pd.read_csv(path, sep='\t', error_bad_lines=False), size=size)
+    def from_file(file_name, valid_frac=None, size=None):
+        f = open(os.path.dirname(__file__) + '/../data/' + file_name)
+        if file_name.endswith('.json'):
+            dataset = PairRelDataset(pd.read_json(f, lines=True), size=size)
+        elif file_name.endswith('.tsv'):
+            dataset = PairRelDataset(pd.read_csv(f, sep='\t', error_bad_lines=False), size=size)
         else:
             raise AttributeError('Could not recognize file type')
 

ADA/server/agent/target_extraction/entity_annotation.py

@@ -111,7 +111,7 @@ class EntityAnnotator:
 
             os.system('clear')
 
-            print(fg.li_green + '{} entities annotated'.format(self.n_annotated) + fg.rs)
+            print(fg.li_green + '{} nouns annotated'.format(self.n_annotated) + fg.rs)
             print('')
 
             print(fg.li_black + 'root:       \'r\'' + fg.rs)
@@ -249,11 +249,12 @@ class EntityAnnotator:
 
     def pair_relations_for_text(self, text, nan_entities=None):
         single_tokens = word_tokenize(text)
-        all_tokens = set().union(*[single_tokens, self.phraser[single_tokens]])
+        tagged_single = pos_tag(single_tokens)
+        tagged_all = set().union(*[tagged_single, pos_tag(self.phraser[single_tokens])])
 
         entity_mentions = []
         for n in PreOrderIter(self.root):
-            cont, mention = self.mention_in_text(all_tokens, node=n)
+            cont, mention = self.mention_in_text(tagged_all, node=n)
             if not cont:
                 # many mentions of same entity
                 return None
@@ -269,7 +270,7 @@ class EntityAnnotator:
         if nan_entities is not None and len(entity_mentions) == 1:
             nan_mention = None
             for term in nan_entities:
-                cont, mention = self.mention_in_text(all_tokens, term=term)
+                cont, mention = self.mention_in_text(tagged_all, term=term)
                 if not cont:
                     # many mentions of term
                     return None
@@ -286,10 +287,11 @@ class EntityAnnotator:
 
     # returns True, (synonym of node / term / None) if there is exactly one or zero such occurrence,
     # otherwise False, None, None
-    def mention_in_text(self, tokens, node=None, term=None):
+    def mention_in_text(self, tagged_tokens, node=None, term=None):
         mention = None
         for syn in ({syn.lower() for syn in self.synset[node]} if node is not None else {term}):
-            n_matches = sum(1 for token in tokens if syn == token.lower().replace('_', ' '))
+            n_matches = sum(1 for token, tag in tagged_tokens
+                            if syn == token.lower().replace('_', ' ') and tag.startswith('NN'))
             if n_matches > 1:
                 return False, None
             if n_matches == 1:
@@ -301,11 +303,12 @@ class EntityAnnotator:
 
     def entity_mentions_in_text(self, text, all_entities):
         single_tokens = word_tokenize(text)
-        all_tokens = set().union(*[single_tokens, self.phraser[single_tokens]])
+        tagged_single = pos_tag(single_tokens)
+        tagged_all = set().union(*[tagged_single, pos_tag(self.phraser[single_tokens])])
 
         entity_mention = None
         for entity, is_aspect in all_entities:
-            cont, mention = self.mention_in_text(all_tokens, term=entity)
+            cont, mention = self.mention_in_text(tagged_all, term=entity)
             if not cont:
                 # many mentions of same entity
                 return None
@@ -355,12 +358,5 @@ class EntityAnnotator:
         return text, rels
 
 
-ann: EntityAnnotator = EntityAnnotator.load_saved('acoustic_guitar_annotator.pickle')
-ann.save_annotated_entities('BERT/data/annotated_acoustic_guitar_review_entities.tsv')
-ann: EntityAnnotator = EntityAnnotator.load_saved('camera_entity_annotator.pickle')
-ann.save_annotated_entities('BERT/data/annotated_camera_review_entities.tsv')
-ann: EntityAnnotator = EntityAnnotator.load_saved('laptop_entity_annotator.pickle')
-ann.save_annotated_entities('BERT/data/annotated_laptop_review_entities.tsv')
-ann: EntityAnnotator = EntityAnnotator.load_saved('backpack_entity_annotator.pickle')
-ann.save_annotated_entities('BERT/data/annotated_backpack_review_entities.tsv')
-
+ea = EntityAnnotator.load_saved('example_annotator.pickle')
+ea.annotate()

ADA/server/agent/target_extraction/full_pass.py

+from agent.target_extraction.BERT.entity_extractor.bert_entity_extractor import BertEntityExtractor
+from agent.target_extraction.BERT.relation_extractor.bert_rel_extractor import BertRelExtractor
+from agent.target_extraction.BERT.data.combine_files import combine_files
+# from agent.target_extraction.entity_annotation import EntityAnnotator
+
+# ann: EntityAnnotator = EntityAnnotator.load_saved('acoustic_guitar_annotator.pickle')
+# ann.save_annotated_pairs('BERT/data/annotated_acoustic_guitar_review_pairs.tsv')
+# ann.save_annotated_entities('BERT/data/annotated_acoustic_guitar_review_entities.tsv')
+# ann: EntityAnnotator = EntityAnnotator.load_saved('camera_entity_annotator.pickle')
+# ann.save_annotated_pairs('BERT/data/annotated_camera_review_pairs.tsv')
+# ann.save_annotated_entities('BERT/data/annotated_camera_review_entities.tsv')
+# ann: EntityAnnotator = EntityAnnotator.load_saved('laptop_entity_annotator.pickle')
+# ann.save_annotated_pairs('BERT/data/annotated_laptop_review_pairs.tsv')
+# ann.save_annotated_entities('BERT/data/annotated_laptop_review_entities.tsv')
+# ann: EntityAnnotator = EntityAnnotator.load_saved('backpack_entity_annotator.pickle')
+# ann.save_annotated_pairs('BERT/data/annotated_backpack_review_pairs.tsv')
+# ann.save_annotated_entities('BERT/data/annotated_backpack_review_entities.tsv')
+#
+
+# entity_files = [
+#     'BERT/data/annotated_camera_review_entities.tsv',
+#     'BERT/data/annotated_backpack_review_entities.tsv',
+#     'BERT/data/annotated_laptop_review_entities.tsv',
+#     'BERT/data/annotated_acoustic_guitar_review_entities.tsv',
+#     'BERT/data/annotated_cardigan_review_entities.tsv'
+# ]
+# entity_output_file = 'BERT/data/camera_backpack_laptop_guitar_cardigan_review_entities_2.tsv'
+#
+# pair_files = [
+#     'BERT/data/annotated_camera_review_pairs.tsv',
+#     'BERT/data/annotated_backpack_review_pairs.tsv',
+#     'BERT/data/annotated_laptop_review_pairs.tsv',
+#     'BERT/data/annotated_acoustic_guitar_review_pairs.tsv',
+#     'BERT/data/annotated_cardigan_review_pairs.tsv'
+# ]
+# pair_output_file = 'BERT/data/camera_backpack_laptop_guitar_cardigan_review_pairs_2.tsv'
+#
+# for n in range(1, 6):
+#     combine_files(entity_files[:n], 'BERT/data/review_entities_' + str(n) + '.tsv', total_size=50000)
+#     combine_files(pair_files[:n], 'BERT/data/review_pairs_' + str(n) + '.tsv', total_size=50000)
+
+#
+# combine_files(entity_files, entity_output_file)
+# combine_files(pair_files, pair_output_file)
+
+for n in range(1, 6):
+    BertRelExtractor.train_and_validate('review_pairs_' + str(n) + '.tsv',
+                                        'rel_extractor_' + str(n) + '_products')
+    BertEntityExtractor.train_and_validate('review_entities_' + str(n) + '.tsv',
+                                           'entity_extractor_' + str(n) + '_products')

ADA/server/agent/target_extraction/target_extractor.py

@@ -16,16 +16,117 @@ from agent.target_extraction.BERT.entity_extractor.entity_dataset import EntityD
 from agent.target_extraction.BERT.entity_extractor.bert_entity_extractor import BertEntityExtractor
 from agent.target_extraction.BERT.relation_extractor.pair_rel_dataset import PairRelDataset
 from agent.target_extraction.BERT.relation_extractor.bert_rel_extractor import BertRelExtractor
-from pathos.multiprocessing import ProcessingPool as Pool
-import itertools
+from pandarallel import pandarallel
 
-np.set_printoptions(precision=3, threshold=np.inf, suppress=True)
+np.set_printoptions(precision=4, threshold=np.inf, suppress=True)
 stop_words = stopwords.words('english')
 wnl = WordNetLemmatizer()
 sentiment_lexicon = pd.read_csv('data/NRC-Sentiment-Lexicon-Wordlevel-v0.92.tsv', sep='\t', index_col=0)
-entity_extractor_path = 'BERT/entity_extractor/trained_bert_entity_extractor_camera_backpack_laptop.pt'
-rel_extractor_path = 'BERT/relation_extractor/trained_bert_rel_extractor_camera_backpack_laptop_no_nan.pt'
-pool = Pool(2)
+entity_extractor_path = 'BERT/entity_extractor/entity_extractor_five_products.pt'
+rel_extractor_path = 'BERT/relation_extractor/rel_extractor_five_products.pt'
+pandarallel.initialize()
+
+
+def ngrams(tagged_tokens, phraser):
+    tokens, tags = zip(*tagged_tokens)
+    unfiltered = [term.split('_') for term in phraser[tokens]]
+    tagged_unfiltered = []
+    n = 0
+    for term in unfiltered:
+        tagged_unfiltered.append([(subterm, list(tags)[n + idx]) for idx, subterm in enumerate(term)])
+        n += len(term)
+
+    return [subterm for term in tagged_unfiltered for subterm in filter_ngram(term)]
+
+
+def filter_ngram(term):
+    if len(term) > 1 and (any(not re.compile('NN|JJ').match(tag) for _, tag in term)
+                          or any(tag.startswith('JJ') and polar_adjective(t) for t, tag in term)):
+        return [subterm for subterm, _ in term]
+    return [' '.join([subterm for subterm, _ in term])]
+
+
+def polar_adjective(adj):
+    return adj in sentiment_lexicon.index and (sentiment_lexicon.loc[adj]['positive'] == 1 or
+                                               sentiment_lexicon.loc[adj]['negative'] == 1)
+
+
+def count_phrase_nouns(tagged_tokens, tagged_ngrams):
+
+    def is_noun(pos_tagged):
+        word, tag = pos_tagged
+        return tag.startswith('NN') and word not in string.punctuation and word not in stop_words
+
+    # true if term is not a preposition and does not include special characters
+    def is_valid_term(pos_tagged):
+        alpha_numeric_pat = '^\w+$'
+        word, tag = pos_tagged
+        return tag != 'IN' and re.match(alpha_numeric_pat, word)
+
+    nouns = []
+    word_idx = 0
+    for token, _ in tagged_ngrams:
+        if ' ' in token:
+            words = token.split(' ')
+            word_range = range(word_idx, word_idx + len(words))
+            has_noun = any(is_noun(tagged_tokens[i]) for i in word_range)
+            all_terms_valid = all(is_valid_term(tagged_tokens[i]) for i in word_range)
+            if has_noun and all_terms_valid:
+                nouns.append(token)
+            word_idx += len(words)
+        else:
+            token_is_noun = is_noun(tagged_tokens[word_idx])
+            is_valid = is_valid_term(tagged_tokens[word_idx])
+            if len(token) > 1 and token_is_noun and is_valid:
+                nouns.append(token)
+            word_idx += 1
+    return nouns
+
+
+def entity_mentions_in_text(text, tagged_tokens, tagged_ngrams, entities):
+    all_tokens = {t for t, tag in set().union(*[tagged_tokens, tagged_ngrams]) if tag.startswith('NN')}
+
+    entity_mention = None
+    for entity in entities:
+        n_mentions = sum(1 for token in all_tokens if entity == token.lower())
+        if n_mentions > 1:
+            # many mentions of same entity
+            return None
+        if n_mentions == 1:
+            if entity_mention is None:
+                entity_mention = entity
+            elif entity_mention in entity:
+                entity_mention = entity
+            elif entity not in entity_mention:
+                # text cannot have more than one entity mention, unless one is a subset of the other,
+                # in which case the longer one is taken
+                return None
+
+    if entity_mention is not None:
+        return text, [{'text': entity_mention}]
+
+    return None
+
+
+def pair_relations_for_text(text, tagged_ngrams, aspects, syn_dict):
+
+    def overlapping_terms(ts, t):
+        if len(ts) == 0:
+            return False
+        return any(t in t2.split(' ') if len(t) < len(t2) else t2 in t.split(' ') for t2 in ts)
+
+    found_aspects = []
+    for aspect in aspects:
+        found_form = False
+        for form in syn_dict[aspect]:
+            if any(t == form and tag.startswith('NN') for t, tag in tagged_ngrams):
+                if len(found_aspects) > 1 or found_form or overlapping_terms(found_aspects, form):
+                    # cannot have more than two aspects, or two forms of the same aspect, or overlapping terms
+                    return None
+                found_aspects.append(form)
+                found_form = True
+
+    return (text, [{'em1Text': found_aspects[0], 'em2Text': found_aspects[1]}]) if len(found_aspects) == 2 else None
 
 
 class TargetExtractor:
@@ -39,7 +140,7 @@ class TargetExtractor:
 
     # word2vec
     MIN_TERM_COUNT = 100
-    SYNONYM_SIMILARITY = 0.12
+    SYNONYM_SIMILARITY = 0.11
     SYNONYM_SIMILARITY_PRODUCT = 0.09
     WV_SIZE = 100
     WV_WINDOW = 7
@@ -54,36 +155,36 @@ class TargetExtractor:
         self.file_path = file_path
 
         print('tokenizing phrases...')
-        # tokenize and normalize phrases
-        texts = TargetExtractor.obtain_texts(file_path, text_column)
-        self.sentences = list(itertools.chain.from_iterable(pool.map(sent_tokenize, texts)))
-        self.sentences = pool.map(lambda s: s.replace('_', ' ').lower(), self.sentences)
-        self.phrases = pool.map(word_tokenize, self.sentences)
+        self.texts = TargetExtractor.obtain_texts(file_path, text_column, n=50000)
+        # obtain normalized sentences
+        self.texts = self.texts.rename(columns={text_column: 'sentence'})
+        self.texts['sentence'] = self.texts['sentence'].parallel_apply(sent_tokenize)
+        self.texts = self.texts.explode('sentence').reset_index(drop=True)
+        self.texts['sentence'] = self.texts['sentence'].parallel_apply(lambda s: s.replace('_', ' ').lower())
+        # obtain tokens and their pos tags in a new column
+        self.texts['tokens'] = self.texts['sentence'].parallel_apply(lambda s: pos_tag(word_tokenize(s)))
 
         print('obtaining n-grams...')
-        # train bigram map
-        bigram = Phrases(self.phrases, threshold=TargetExtractor.PHRASE_THRESHOLD)
-        trigram = Phrases(bigram[self.phrases], threshold=TargetExtractor.PHRASE_THRESHOLD)
-        self.phraser = Phraser(trigram)
-        self.ngram_phrases = self.ngrams(self.phrases)
+        # train ngrams and their pos tags in a new column
+        tokens = [[t for t, tag in tagged_ts] for tagged_ts in self.texts['tokens']]
+        bigram = Phrases(tokens, threshold=TargetExtractor.PHRASE_THRESHOLD)
+        trigram = Phrases(bigram[tokens], threshold=TargetExtractor.PHRASE_THRESHOLD)
+        phraser = Phraser(trigram)
+        self.texts['ngrams'] = self.texts.apply(lambda row: ngrams(row.tokens, phraser), axis=1)
+        self.texts['ngrams'] = self.texts['ngrams'].parallel_apply(lambda t: pos_tag(t))
 
         print('counting terms...')
         # count terms
         self.counter = self.count_nouns()
-        self.total_count = sum(self.counter.values())
-
-        self.save()
 
         print('training word2vec model...')
         # train word2vec model
         self.wv = self.get_word2vec_model(size=TargetExtractor.WV_SIZE, window=TargetExtractor.WV_WINDOW,
                                           min_count=TargetExtractor.MIN_TERM_COUNT)
 
-        self.save()
-
         print('mining aspects...')
         # mine aspects
-        self.aspects, self.counts = self.get_aspects(self.counter)
+        self.aspects, self.counts = self.get_aspects()
 
         print('extracting synonyms...')
         # obtain synonyms
@@ -96,15 +197,9 @@ class TargetExtractor:
         self.counts = {aspect: sum(self.counts[syn] for syn in self.syn_dict[aspect]) for aspect in self.aspects}
         self.aspects = sorted(self.aspects, key=self.counts.get, reverse=True)
 
-        print(self.syn_dict)
-
-        self.save()
-
         print('extracting relatedness matrix...')
         self.relatedness_matrix = self.get_bert_relations()
 
-        self.save()
-
         print('extracting aspect tree...')
         self.tree = self.get_product_tree()
 
@@ -126,52 +221,37 @@ class TargetExtractor:
 
     @staticmethod
     def obtain_texts(path, col, n=None):
-        file = pd.read_csv(path, sep='\t', error_bad_lines=False)
-        file = file[~file[col].isnull()]
-        if n and n < len(file.index):
-            file = file.sample(frac=1).reset_index(drop=True)
-            file = file.head(n)
-        texts = [text for _, text in file[col].items() if not pd.isnull(text)]
+        texts = pd.read_csv(path, usecols=[col], squeeze=False, sep='\t', error_bad_lines=False)
+        texts = texts[~texts[col].isnull()]
+        texts = texts[texts[col] != '']