2 files changed, 359 insertions, 0 deletions

diff --git a/Helpers.py b/Helpers.py
new file mode 100644
index 0000000..7c615ab
--- /dev/null
+++ b/Helpers.py
@@ -0,0 +1,157 @@
+import itertools
+
+import numpy as np
+from sklearn.model_selection import train_test_split as split_data
+
+import pandas as pd
+from gensim.models import KeyedVectors
+from keras.preprocessing.sequence import pad_sequences
+
+
+class Data(object):
+    def __init__(
+        self,
+        source_lang,
+        target_lang,
+        data_file,
+        max_len=None,
+        instances=1000,
+        vocab_limit=None,
+        sentence_cols=None,
+        score_col=None,
+    ):
+        self.source_lang = source_lang
+        self.target_lang = target_lang
+        self.data_file = data_file
+        self.max_len = max_len
+        self.instances = instances
+        self.vocab_size = 1
+        self.vocab_limit = vocab_limit
+
+        if sentence_cols is None:
+            self.sequence_cols = [
+                f"{source_lang} definition",
+                f"{target_lang} definition",
+            ]
+        else:
+            self.sequence_cols = sentence_cols
+
+        if score_col is None:
+            self.score_col = "is same"
+        else:
+            self.score_col = score_col
+
+        self.x_train = list()
+        self.y_train = list()
+        self.x_val = list()
+        self.y_val = list()
+        self.vocab = set("PAD")
+        self.word_to_id = {"PAD": 0}
+        self.id_to_word = {0: "PAD"}
+        self.word_to_count = dict()
+        self.run()
+
+    def text_to_word_list(self, text):
+        """ Pre process and convert texts to a list of words """
+        text = str(text)
+        text = text.split()
+        return text
+
+    def load_data(self):
+        # Load data set
+        data_df = pd.read_csv(self.data_file, sep="\t")
+
+        # Iterate over required sequences of provided dataset
+        for index, row in data_df.iterrows():
+            # Iterate through the text of both questions of the row
+            for sequence in self.sequence_cols:
+                s2n = []  # Sequences with words replaces with indices
+                for word in self.text_to_word_list(row[sequence]):
+                    if word not in self.vocab:
+                        self.vocab.add(word)
+                        self.word_to_id[word] = self.vocab_size
+                        self.word_to_count[word] = 1
+                        s2n.append(self.vocab_size)
+                        self.id_to_word[self.vocab_size] = word
+                        self.vocab_size += 1
+                    else:
+                        self.word_to_count[word] += 1
+                        s2n.append(self.word_to_id[word])
+
+                # Replace |sequence as word| with |sequence as number| representation
+                data_df.at[index, sequence] = s2n
+        return data_df
+
+    def pad_sequences(self):
+        if self.max_len == 0:
+            self.max_len = max(
+                max(len(seq) for seq in self.x_train[0]),
+                max(len(seq) for seq in self.x_train[1]),
+                max(len(seq) for seq in self.x_val[0]),
+                max(len(seq) for seq in self.x_val[1]),
+            )
+
+        # Zero padding
+        for dataset, side in itertools.product([self.x_train, self.x_val], [0, 1]):
+            if self.max_len:
+                dataset[side] = pad_sequences(dataset[side], maxlen=self.max_len)
+            else:
+                dataset[side] = pad_sequences(dataset[side])
+
+    def run(self):
+        # Loading data and building vocabulary.
+        data_df = self.load_data()
+
+        X = data_df[self.sequence_cols]
+        Y = data_df[self.score_col]
+
+        self.x_train, self.x_val, self.y_train, self.y_val = split_data(
+            X, Y, test_size=self.instances, shuffle=False
+        )
+
+        # Split to lists
+        self.x_train = [self.x_train[column] for column in self.sequence_cols]
+        self.x_val = [self.x_val[column] for column in self.sequence_cols]
+
+        # Convert labels to their numpy representations
+        self.y_train = self.y_train.values
+        self.y_val = self.y_val.values
+
+        # Padding Sequences.
+        self.pad_sequences()
+
+
+class Get_Embedding(object):
+    def __init__(self, source_lang, target_lang, source_emb, target_emb, word_index):
+        self.embedding_size = 300  # Default dimensionality
+        self.embedding_matrix = self.create_embed_matrix(
+            source_lang, target_lang, source_emb, target_emb, word_index
+        )
+
+    def create_embed_matrix(
+        self, source_lang, target_lang, source_emb, target_emb, word_index
+    ):
+        source_vecs = KeyedVectors.load_word2vec_format(source_emb)
+        target_vecs = KeyedVectors.load_word2vec_format(target_emb)
+
+        # Prepare Embedding Matrix.
+        embedding_matrix = np.zeros((len(word_index) + 1, self.embedding_size))
+
+        # word has either __source or __target appended
+        for key, i in word_index.items():
+            if "__" not in key:
+                print("Skipping {}".format(key))
+                continue
+
+            word, lang = key.split("__")
+
+            if lang == source_lang:
+                if word in source_vecs.vocab:
+                    embedding_matrix[i] = source_vecs.word_vec(word)
+            else:
+                if word in target_vecs.vocab:
+                    embedding_matrix[i] = target_vecs.word_vec(word)
+
+        del source_vecs
+        del target_vecs
+        return embedding_matrix
diff --git a/learn_and_predict.py b/learn_and_predict.py
new file mode 100644
index 0000000..36c56f2
--- /dev/null
+++ b/learn_and_predict.py
@@ -0,0 +1,202 @@
+import argparse
+import csv
+
+import numpy as np
+
+import keras
+import keras.backend as K
+from Helpers import Data, Get_Embedding
+from keras.layers import LSTM, Embedding, Input, Lambda, concatenate
+from keras.models import Model
+
+
+def get_learning_rate(epoch=None, model=None):
+    return np.round(float(K.get_value(model.optimizer.lr)), 5)
+
+
+def make_cosine_func(hidden_size=50):
+    def exponent_neg_cosine_similarity(x):
+        """ Helper function for the similarity estimate of the LSTMs outputs """
+        leftNorm = K.l2_normalize(x[:, :hidden_size], axis=-1)
+        rightNorm = K.l2_normalize(x[:, hidden_size:], axis=-1)
+        return K.sum(K.prod([leftNorm, rightNorm], axis=0), axis=1, keepdims=True)
+
+    return exponent_neg_cosine_similarity
+
+
+def main(args):
+
+    source_lang = args.source_lang
+    target_lang = args.target_lang
+    hidden_size = args.hidden_size
+    max_len = args.max_len
+    num_iters = args.num_iters
+    data_file = args.data_file
+    learning_rate = args.learning_rate
+    batch = args.batch
+
+    data = Data(source_lang, target_lang, data_file, max_len)
+
+    x_train = data.x_train
+    y_train = data.y_train
+    x_predict = data.x_val
+    y_predict = data.y_val
+    vocab_size = data.vocab_size
+    max_len = data.max_len
+
+    # https://stackoverflow.com/a/10741692/3005749
+    x = data.y_val
+    y = np.bincount(x.astype(np.int32))
+    ii = np.nonzero(y)[0]
+    assert ii == 1
+    assert y[ii] == 1000  # hardcoded for now
+
+    if not batch:
+        print(f"Source Lang: {source_lang}")
+        print(f"Target Lang: {target_lang}")
+        print(f"Using {len(x_train[0])} pairs to learn")
+        print(f"Predicting {len(y_predict)} pairs")
+        print(f"Vocabulary size: {vocab_size}")
+        print(f"Maximum sequence length: {max_len}")
+
+    source_emb_file = args.source_emb_file
+    target_emb_file = args.target_emb_file
+
+    embedding = Get_Embedding(
+        source_lang, target_lang, source_emb_file, target_emb_file, data.word_to_id
+    )
+    embedding_size = embedding.embedding_matrix.shape[1]
+
+    seq_1 = Input(shape=(max_len,), dtype="int32", name="sequence1")
+    seq_2 = Input(shape=(max_len,), dtype="int32", name="sequence2")
+
+    embed_layer = Embedding(
+        output_dim=embedding_size,
+        input_dim=vocab_size + 1,
+        input_length=max_len,
+        trainable=False,
+    )
+    embed_layer.build((None,))
+    embed_layer.set_weights([embedding.embedding_matrix])
+
+    input_1 = embed_layer(seq_1)
+    input_2 = embed_layer(seq_2)
+
+    l1 = LSTM(units=hidden_size)
+
+    l1_out = l1(input_1)
+    l2_out = l1(input_2)
+
+    concats = concatenate([l1_out, l2_out], axis=-1)
+
+    out_func = make_cosine_func(hidden_size)
+
+    main_output = Lambda(out_func, output_shape=(1,))(concats)
+
+    model = Model(inputs=[seq_1, seq_2], outputs=[main_output])
+
+    opt = keras.optimizers.Adadelta(lr=learning_rate, clipnorm=1.25)
+
+    model.compile(optimizer=opt, loss="mean_squared_error", metrics=["accuracy"])
+    model.summary()
+
+    adjuster = keras.callbacks.ReduceLROnPlateau(
+        monitor="val_acc", patience=5, verbose=1, factor=0.5, min_lr=0.0001
+    )
+
+    history = model.fit(
+        x_train,
+        y_train,
+        validation_data=(x_predict, y_predict),
+        epochs=num_iters,
+        batch_size=32,
+        verbose=1,
+        callbacks=[adjuster],
+    )
+
+    target_sents = x_predict[1]
+    precision_at_one = 0
+    precision_at_ten = 0
+    for index, sent in enumerate(x_predict[0]):
+        source_sents = np.array([sent] * 1000)
+        to_predict = [source_sents, target_sents]
+        preds = model.predict(to_predict)
+        ind = np.argpartition(preds.ravel(), -10)[-10:]
+        if index in ind:
+            precision_at_ten += 1
+        if np.argmax(preds.ravel()) == index:
+            precision_at_one += 1
+
+    training_samples = len(x_train[0])
+    validation_samples = len(y_predict)
+    fields = [
+        source_lang,
+        target_lang,
+        training_samples,
+        validation_samples,
+        precision_at_one,
+        precision_at_ten,
+    ]
+
+    if not batch:
+        print(f"P@1: {precision_at_one/1000}, {precision_at_one} defs")
+    else:
+        with open("supervised.csv", "a") as f:
+            writer = csv.writer(f)
+            writer.writerow(fields)
+
+
+if __name__ == "__main__":
+
+    parser = argparse.ArgumentParser()
+
+    parser.add_argument(
+        "-sl", "--source_lang", type=str, help="Source language.", default="english"
+    )
+    parser.add_argument(
+        "-tl", "--target_lang", type=str, help="Target language.", default="italian"
+    )
+    parser.add_argument("-df", "--data_file", type=str, help="Path to dataset.")
+    parser.add_argument(
+        "-es",
+        "--source_emb_file",
+        type=str,
+        help="Path to Source (English) Embedding File.",
+    )
+    parser.add_argument(
+        "-et", "--target_emb_file", type=str, help="Path to Target Embedding File."
+    )
+    parser.add_argument(
+        "-l",
+        "--max_len",
+        type=int,
+        help="Maximum number of words in a sentence.",
+        default=20,
+    )
+    parser.add_argument(
+        "-z",
+        "--hidden_size",
+        type=int,
+        help="Number of Units in LSTM layer.",
+        default=50,
+    )
+    parser.add_argument(
+        "-b",
+        "--batch",
+        action="store_true",
+        help="running in batch (store results to csv) or"
+        + "running in a single instance (output the results)",
+    )
+    parser.add_argument(
+        "-n", "--num_iters", type=int, help="Number of iterations/epochs.", default=7
+    )
+    parser.add_argument(
+        "-lr",
+        "--learning_rate",
+        type=float,
+        help="Learning rate for optimizer.",
+        default=1.0,
+    )
+
+    args = parser.parse_args()
+    main(args)