AI-For-Beginners/translations/pcm/lessons/5-NLP/15-LanguageModeling/CBoW-PyTorch.ipynb

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{
"cells": [
{
"cell_type": "markdown",
"metadata": {
"id": "NXTSugt6ieXh"
},
"source": [
"## Training CBoW Model\n",
"\n",
"Dis notebook na part of [AI for Beginners Curriculum](http://aka.ms/ai-beginners)\n",
"\n",
"For dis example, we go train CBoW language model to get our own Word2Vec embedding space. We go use AG News dataset as di source of text.\n"
]
},
{
"cell_type": "code",
"source": [
"import torch\n",
"import torchtext\n",
"import os\n",
"import collections\n",
"import builtins\n",
"import random\n",
"import numpy as np"
],
"metadata": {
"id": "q-UiiJUKaxHj"
},
"execution_count": null,
"outputs": []
},
{
"cell_type": "code",
"source": [
"device = torch.device(\"cuda\" if torch.cuda.is_available() else \"cpu\")"
],
"metadata": {
"id": "TFbR8CZaTZ1q"
},
"execution_count": null,
"outputs": []
},
{
"cell_type": "markdown",
"source": [
"First make we load our dataset and define tokenizer and vocabulary. We go set `vocab_size` to 5000 to reduce computation small.\n"
],
"metadata": {
"id": "HIwC7lI5T-ov"
}
},
{
"cell_type": "code",
"source": [
"def load_dataset(ngrams = 1, min_freq = 1, vocab_size = 5000 , lines_cnt = 500):\n",
" tokenizer = torchtext.data.utils.get_tokenizer('basic_english')\n",
" print(\"Loading dataset...\")\n",
" test_dataset, train_dataset = torchtext.datasets.AG_NEWS(root='./data')\n",
" train_dataset = list(train_dataset)\n",
" test_dataset = list(test_dataset)\n",
" classes = ['World', 'Sports', 'Business', 'Sci/Tech']\n",
" print('Building vocab...')\n",
" counter = collections.Counter()\n",
" for i, (_, line) in enumerate(train_dataset):\n",
" counter.update(torchtext.data.utils.ngrams_iterator(tokenizer(line),ngrams=ngrams))\n",
" if i == lines_cnt:\n",
" break\n",
" vocab = torchtext.vocab.Vocab(collections.Counter(dict(counter.most_common(vocab_size))), min_freq=min_freq)\n",
" return train_dataset, test_dataset, classes, vocab, tokenizer"
],
"metadata": {
"id": "wdZuygtgiuLG"
},
"execution_count": null,
"outputs": []
},
{
"cell_type": "code",
"source": [
"train_dataset, test_dataset, _, vocab, tokenizer = load_dataset()"
],
"metadata": {
"colab": {
"base_uri": "https://localhost:8080/"
},
"id": "4d1nU1gsivGu",
"outputId": "949fe272-ae0e-49f5-c373-6703458b3a74"
},
"execution_count": null,
"outputs": [
{
"output_type": "stream",
"name": "stdout",
"text": [
"Loading dataset...\n",
"Building vocab...\n"
]
}
]
},
{
"cell_type": "code",
"source": [
"def encode(x, vocabulary, tokenizer = tokenizer):\n",
" return [vocabulary[s] for s in tokenizer(x)]"
],
"metadata": {
"id": "1XDYNhG8ToFV"
},
"execution_count": null,
"outputs": []
},
{
"cell_type": "markdown",
"metadata": {
"id": "LIlQk6_PaHVY"
},
"source": [
"## CBoW Model\n",
"\n",
"CBoW dey learn how to sabi predict one word based on di $2N$ words wey dey near am. For example, wen $N=1$, we go fit get di following pairs from di sentence *I like to train networks*: (like,I), (I, like), (to, like), (like,to), (train,to), (to, train), (networks, train), (train,networks). For here, di first word na di neighboring word wey we go use as input, and di second word na di one we dey try predict.\n",
"\n",
"To build network wey go fit predict di next word, we go need supply di neighboring word as input, and make di output na di word number. Di architecture of CBoW network be like dis:\n",
"\n",
"* Di input word go pass through di embedding layer. Dis embedding layer go be our Word2Vec embedding, so we go define am separate as `embedder` variable. For dis example, we go use embedding size = 30, even though you fit wan try test higher dimensions (real word2vec dey use 300).\n",
"* Di embedding vector go then pass enter one linear layer wey go predict di output word. So e go get `vocab_size` neurons.\n",
"\n",
"For di output, if we use `CrossEntropyLoss` as loss function, we go need provide just di word numbers as di expected results, without one-hot encoding.\n"
]
},
{
"cell_type": "code",
"source": [
"vocab_size = len(vocab)\n",
"\n",
"embedder = torch.nn.Embedding(num_embeddings = vocab_size, embedding_dim = 30)\n",
"model = torch.nn.Sequential(\n",
" embedder,\n",
" torch.nn.Linear(in_features = 30, out_features = vocab_size),\n",
")\n",
"\n",
"print(model)"
],
"metadata": {
"colab": {
"base_uri": "https://localhost:8080/"
},
"id": "akKTcKQKkfl2",
"outputId": "da687e3e-a8ec-4c1a-e456-ab8cd6ac7dad"
},
"execution_count": null,
"outputs": [
{
"output_type": "stream",
"name": "stdout",
"text": [
"Sequential(\n",
" (0): Embedding(5002, 30)\n",
" (1): Linear(in_features=30, out_features=5002, bias=True)\n",
")\n"
]
}
]
},
{
"cell_type": "markdown",
"metadata": {
"id": "Nud6jgGPaHVa"
},
"source": [
"## How to Prepare Training Data\n",
"\n",
"Make we program di main function wey go fit calculate CBoW word pairs from text. Dis function go allow us set di window size, and e go return set of pairs - input and output word. Make you sabi say dis function fit work for words, and e fit still work for vectors/tensors - wey go allow us encode di text before we pass am give `to_cbow` function.\n"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {
"colab": {
"base_uri": "https://localhost:8080/"
},
"id": "x-dsXygOieXn",
"outputId": "c2218280-e540-40ba-9546-efe48d0d714f"
},
"outputs": [
{
"output_type": "stream",
"name": "stdout",
"text": [
"[['like', 'I'], ['to', 'I'], ['I', 'like'], ['to', 'like'], ['train', 'like'], ['I', 'to'], ['like', 'to'], ['train', 'to'], ['networks', 'to'], ['like', 'train'], ['to', 'train'], ['networks', 'train'], ['to', 'networks'], ['train', 'networks']]\n",
"[[232, 172], [5, 172], [172, 232], [5, 232], [0, 232], [172, 5], [232, 5], [0, 5], [1202, 5], [232, 0], [5, 0], [1202, 0], [5, 1202], [0, 1202]]\n"
]
}
],
"source": [
"def to_cbow(sent,window_size=2):\n",
" res = []\n",
" for i,x in enumerate(sent):\n",
" for j in range(max(0,i-window_size),min(i+window_size+1,len(sent))):\n",
" if i!=j:\n",
" res.append([sent[j],x])\n",
" return res\n",
"\n",
"print(to_cbow(['I','like','to','train','networks']))\n",
"print(to_cbow(encode('I like to train networks', vocab)))"
]
},
{
"cell_type": "markdown",
"metadata": {
"id": "XVaaDLjaaHVb"
},
"source": [
"Make we prepare di training dataset. We go check all di news, call `to_cbow` to get di list of word pairs, and add di pairs to `X` and `Y`. For di sake of time, we go only consider di first 10k news items - you fit remove di limitation if you get more time to wait, and wan get better embeddings :)\n"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {
"id": "54b-Gd9TieXo"
},
"outputs": [],
"source": [
"X = []\n",
"Y = []\n",
"for i, x in zip(range(10000), train_dataset):\n",
" for w1, w2 in to_cbow(encode(x[1], vocab), window_size = 5):\n",
" X.append(w1)\n",
" Y.append(w2)\n",
"\n",
"X = torch.tensor(X)\n",
"Y = torch.tensor(Y)"
]
},
{
"cell_type": "markdown",
"source": [
"We go still change dat data to one dataset, and make dataloader:\n"
],
"metadata": {
"id": "cwWy0PzXWhN5"
}
},
{
"cell_type": "code",
"source": [
"class SimpleIterableDataset(torch.utils.data.IterableDataset):\n",
" def __init__(self, X, Y):\n",
" super(SimpleIterableDataset).__init__()\n",
" self.data = []\n",
" for i in range(len(X)):\n",
" self.data.append( (Y[i], X[i]) )\n",
" random.shuffle(self.data)\n",
"\n",
" def __iter__(self):\n",
" return iter(self.data)"
],
"metadata": {
"id": "mfoAcGPFZU8p"
},
"execution_count": null,
"outputs": []
},
{
"cell_type": "markdown",
"metadata": {
"id": "e4NQ_-5waHVc"
},
"source": [
"We go still change dat data to one dataset, and make dataloader:\n"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {
"id": "AbLUcojlieXo"
},
"outputs": [],
"source": [
"ds = SimpleIterableDataset(X, Y)\n",
"dl = torch.utils.data.DataLoader(ds, batch_size = 256)"
]
},
{
"cell_type": "markdown",
"metadata": {
"id": "pKQr7sXeaHVc"
},
"source": [
"Make we start di real training now. We go use `SGD` optimizer wit high learning rate. You fit also try play around wit oda optimizers, like `Adam`. We go train for 10 epochs to start wit - and you fit run dis cell again if you wan get even lower loss.\n"
]
},
{
"cell_type": "code",
"source": [
"def train_epoch(net, dataloader, lr = 0.01, optimizer = None, loss_fn = torch.nn.CrossEntropyLoss(), epochs = None, report_freq = 1):\n",
" optimizer = optimizer or torch.optim.Adam(net.parameters(), lr = lr)\n",
" loss_fn = loss_fn.to(device)\n",
" net.train()\n",
"\n",
" for i in range(epochs):\n",
" total_loss, j = 0, 0, \n",
" for labels, features in dataloader:\n",
" optimizer.zero_grad()\n",
" features, labels = features.to(device), labels.to(device)\n",
" out = net(features)\n",
" loss = loss_fn(out, labels)\n",
" loss.backward()\n",
" optimizer.step()\n",
" total_loss += loss\n",
" j += 1\n",
" if i % report_freq == 0:\n",
" print(f\"Epoch: {i+1}: loss={total_loss.item()/j}\")\n",
"\n",
" return total_loss.item()/j"
],
"metadata": {
"id": "HeeCYKr_KF1w"
},
"execution_count": null,
"outputs": []
},
{
"cell_type": "code",
"source": [
"train_epoch(net = model, dataloader = dl, optimizer = torch.optim.SGD(model.parameters(), lr = 0.1), loss_fn = torch.nn.CrossEntropyLoss(), epochs = 10)"
],
"metadata": {
"colab": {
"base_uri": "https://localhost:8080/"
},
"id": "KVgwGtDHgDlT",
"outputId": "2447833f-f0e3-4566-c33d-addbfe2f451d"
},
"execution_count": null,
"outputs": [
{
"output_type": "stream",
"name": "stdout",
"text": [
"Epoch: 1: loss=5.664632366860172\n",
"Epoch: 2: loss=5.632101973960962\n",
"Epoch: 3: loss=5.610399051405015\n",
"Epoch: 4: loss=5.594621561080262\n",
"Epoch: 5: loss=5.582538017415446\n",
"Epoch: 6: loss=5.572900234519603\n",
"Epoch: 7: loss=5.564951676341915\n",
"Epoch: 8: loss=5.558288112064614\n",
"Epoch: 9: loss=5.552576955031129\n",
"Epoch: 10: loss=5.547634165194347\n"
]
},
{
"output_type": "execute_result",
"data": {
"text/plain": [
"5.547634165194347"
]
},
"metadata": {},
"execution_count": 16
}
]
},
{
"cell_type": "markdown",
"metadata": {
"id": "W8u2qXZmaHVd"
},
"source": [
"## Try Word2Vec\n",
"\n",
"To use Word2Vec, make we comot vectors wey match all di words wey dey our vocabulary:\n"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {
"id": "r8TatcXjkU_t"
},
"outputs": [],
"source": [
"vectors = torch.stack([embedder(torch.tensor(vocab[s])) for s in vocab.itos], 0)"
]
},
{
"cell_type": "markdown",
"metadata": {
"id": "3OcX21UOaHVd"
},
"source": [
"Make we see, for example, how di word **Paris** go turn to vector:\n"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {
"colab": {
"base_uri": "https://localhost:8080/"
},
"id": "bz6tAeLzieXp",
"outputId": "5b20850e-4342-45e9-f840-cfac2b4d61d8"
},
"outputs": [
{
"output_type": "stream",
"name": "stdout",
"text": [
"tensor([-0.0915, 2.1224, -0.0281, -0.6819, 1.1219, 0.6458, -1.3704, -1.3314,\n",
" -1.1437, 0.4496, 0.2301, -0.3515, -0.8485, 1.0481, 0.4386, -0.8949,\n",
" 0.5644, 1.0939, -2.5096, 3.2949, -0.2601, -0.8640, 0.1421, -0.0804,\n",
" -0.5083, -1.0560, 0.9753, -0.5949, -1.6046, 0.5774],\n",
" grad_fn=<EmbeddingBackward>)\n"
]
}
],
"source": [
"paris_vec = embedder(torch.tensor(vocab['paris']))\n",
"print(paris_vec)"
]
},
{
"cell_type": "markdown",
"metadata": {
"id": "pHTJlaeYaHVd"
},
"source": [
"E dey interestin to use Word2Vec to find synonyms. Di function wey dey below go return `n` closest words to di input wey you give. To find dem, we go calculate di norm of $|w_i - v|$, wey `v` be di vector wey match di input word, and `w_i` na di encoding of di `i`-th word for di vocabulary. After dat, we go arrange di array and return di indices wey match am using `argsort`, and we go take di first `n` elements for di list, wey dey show di positions of di closest words for di vocabulary.\n"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {
"colab": {
"base_uri": "https://localhost:8080/"
},
"id": "NlZyi-_olFar",
"outputId": "b5dbb163-88c4-4d5a-eaf2-6751f700e98c"
},
"outputs": [
{
"output_type": "execute_result",
"data": {
"text/plain": [
"['microsoft', 'quoted', 'lp', 'rate', 'top']"
]
},
"metadata": {},
"execution_count": 56
}
],
"source": [
"def close_words(x, n = 5):\n",
" vec = embedder(torch.tensor(vocab[x]))\n",
" top5 = np.linalg.norm(vectors.detach().numpy() - vec.detach().numpy(), axis = 1).argsort()[:n]\n",
" return [ vocab.itos[x] for x in top5 ]\n",
"\n",
"close_words('microsoft')"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {
"colab": {
"base_uri": "https://localhost:8080/"
},
"id": "-dQq7xeAln0U",
"outputId": "66f768c3-c248-4bfd-ce4f-c8ffc6d0dd0d"
},
"outputs": [
{
"output_type": "execute_result",
"data": {
"text/plain": [
"['basketball', 'lot', 'sinai', 'states', 'healthdaynews']"
]
},
"metadata": {},
"execution_count": 51
}
],
"source": [
"close_words('basketball')"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {
"colab": {
"base_uri": "https://localhost:8080/"
},
"id": "fJXqK26b29sa",
"outputId": "78f0baba-ffd0-485a-dd87-0a12bedfd7fa"
},
"outputs": [
{
"output_type": "execute_result",
"data": {
"text/plain": [
"['funds', 'travel', 'sydney', 'japan', 'business']"
]
},
"metadata": {},
"execution_count": 77
}
],
"source": [
"close_words('funds')"
]
},
{
"cell_type": "markdown",
"metadata": {
"id": "My0VeTDd3Ji8"
},
"source": [
"## Takeaway\n",
"\n",
"If you sabi use smart techniques like CBoW, you fit train Word2Vec model. You fit also try train skip-gram model wey dem dey train to predict di word wey dey near di central one, and see how e go perform.\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"---\n\n<!-- CO-OP TRANSLATOR DISCLAIMER START -->\n**Disclaimer**: \nDis dokyument don use AI transleshion service [Co-op Translator](https://github.com/Azure/co-op-translator) do di transleshion. Even as we dey try make am correct, abeg make you sabi say machine transleshion fit get mistake or no dey accurate well. Di original dokyument wey dey for im native language na di main source wey you go fit trust. For important mata, e good make you use professional human transleshion. We no go fit take blame for any misunderstanding or wrong interpretation wey fit happen because you use dis transleshion.\n<!-- CO-OP TRANSLATOR DISCLAIMER END -->\n"
]
}
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