{ "cells": [ { "cell_type": "markdown", "metadata": { "id": "IZ6SNYq_tVVC" }, "source": [ "# Intent Classification with BERT\n", "\n", "This notebook demonstrates the fine-tuning of BERT to perform intent classification.\n", "Intent classification tries to map given instructions (sentence in natural language) to a set of predefined intents. \n", "\n", "## What you will learn\n", "\n", "- Load data from csv and preprocess it for training and test\n", "- Load a BERT model from TensorFlow Hub\n", "- Build your own model by combining BERT with a classifier\n", "- Train your own model, fine-tuning BERT as part of that\n", "- Save your model and use it to recognize the intend of instructions\n" ] }, { "cell_type": "markdown", "metadata": { "id": "2PHBpLPuQdmK" }, "source": [ "## About BERT\n", "\n", "[BERT](https://arxiv.org/abs/1810.04805) and other Transformer encoder architectures have been shown to be successful on a variety of tasks in NLP (natural language processing). They compute vector-space representations of natural language that are suitable for use in deep learning models. The BERT family of models uses the Transformer encoder architecture to process each token of input text in the full context of all tokens before and after, hence the name: Bidirectional Encoder Representations from Transformers. \n", "\n", "BERT models are usually pre-trained on a large corpus of text, then fine-tuned for specific tasks.\n" ] }, { "cell_type": "markdown", "metadata": { "id": "SCjmX4zTCkRK" }, "source": [ "## Setup\n" ] }, { "cell_type": "code", "execution_count": 1, "metadata": { "execution": { "iopub.execute_input": "2021-01-13T03:07:33.561260Z", "iopub.status.busy": "2021-01-13T03:07:33.560567Z", "iopub.status.idle": "2021-01-13T03:07:40.852309Z", "shell.execute_reply": "2021-01-13T03:07:40.851601Z" }, "id": "_XgTpm9ZxoN9" }, "outputs": [], "source": [ "import os\n", "#import shutil\n", "import pandas as pd\n", "\n", "import tensorflow as tf\n", "import tensorflow_hub as hub\n", "import tensorflow_text as text\n", "import seaborn as sns\n", "from pylab import rcParams\n", "\n", "import matplotlib.pyplot as plt\n", "tf.get_logger().setLevel('ERROR')\n", "\n", "sns.set(style='whitegrid', palette='muted', font_scale=1.2)\n", "HAPPY_COLORS_PALETTE = [\"#01BEFE\", \"#FFDD00\", \"#FF7D00\", \"#FF006D\", \"#ADFF02\", \"#8F00FF\"]\n", "sns.set_palette(sns.color_palette(HAPPY_COLORS_PALETTE))\n", "rcParams['figure.figsize'] = 12, 8\n", "import warnings\n", "warnings.filterwarnings(\"ignore\")" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Data Access\n", "The data contains various user queries categorized into seven intents. It is hosted on [GitHub](https://github.com/snipsco/nlu-benchmark/tree/master/2017-06-custom-intent-engines) and is first presented in [this paper](https://arxiv.org/abs/1805.10190). In the list below the classes and an example for each class is given:\n", "\n", "* `class`: SearchCreativeWork - `example`:*play hell house song*\n", "* `class`: GetWeather - `example`: *is it windy in boston, mb right now*\n", "* `class`: BookRestaurant - `example`: *book a restaurant for eight people in six years*\n", "* `class`: PlayMusic - `example`: *play the song little robin redbreast*\n", "* `class`: AddToPlaylist - `example`: *add step to me to the 50 clásicos playlist*\n", "* `class`: RateBook - `example`: *give 6 stars to of mice and men*\n", "* `class`: SearchScreeningEvent - `example` : *find fish story*" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "Data can be downloaded from a Google Drive by applying [gdown](https://pypi.org/project/gdown/). In the following code cells the download is invoked only if the corresponding file, does not yet exist at the corresponding location." ] }, { "cell_type": "code", "execution_count": 2, "metadata": {}, "outputs": [], "source": [ "datafolder=\"\"" ] }, { "cell_type": "code", "execution_count": 3, "metadata": {}, "outputs": [], "source": [ "trainfile=datafolder+\"train.csv\"\n", "testfile=datafolder+\"test.csv\"\n", "validfile=datafolder+\"valid.csv\"" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "Next, the downloaded .csv-files for training, validation and test are imported into pandas dataframes:" ] }, { "cell_type": "code", "execution_count": 4, "metadata": {}, "outputs": [], "source": [ "traindf = pd.read_csv(trainfile)\n", "validdf = pd.read_csv(validfile)\n", "testdf = pd.read_csv(testfile)" ] }, { "cell_type": "code", "execution_count": 5, "metadata": {}, "outputs": [ { "data": { "text/html": [ "
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textintent
0listen to westbam alumb allergic on google musicPlayMusic
1add step to me to the 50 clásicos playlistAddToPlaylist
2i give this current textbook a rating value of...RateBook
3play the song little robin redbreastPlayMusic
4please add iris dement to my playlist this is ...AddToPlaylist
\n", "
" ], "text/plain": [ " text intent\n", "0 listen to westbam alumb allergic on google music PlayMusic\n", "1 add step to me to the 50 clásicos playlist AddToPlaylist\n", "2 i give this current textbook a rating value of... RateBook\n", "3 play the song little robin redbreast PlayMusic\n", "4 please add iris dement to my playlist this is ... AddToPlaylist" ] }, "execution_count": 5, "metadata": {}, "output_type": "execute_result" } ], "source": [ "traindf.head()" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "Training data contains 13084 instructions:" ] }, { "cell_type": "code", "execution_count": 6, "metadata": { "scrolled": true }, "outputs": [ { "data": { "text/plain": [ "(13084, 2)" ] }, "execution_count": 6, "metadata": {}, "output_type": "execute_result" } ], "source": [ "traindf.shape" ] }, { "cell_type": "code", "execution_count": 7, "metadata": {}, "outputs": [], "source": [ "trainfeatures=traindf.copy()\n", "trainlabels=trainfeatures.pop(\"intent\")" ] }, { "cell_type": "code", "execution_count": 8, "metadata": {}, "outputs": [], "source": [ "trainfeatures=trainfeatures.values" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "Distribution of class-labels in training-data:" ] }, { "cell_type": "code", "execution_count": 9, "metadata": {}, "outputs": [], "source": [ "#chart = sns.countplot(trainlabels, palette=HAPPY_COLORS_PALETTE)\n", "#plt.title(\"Number of texts per intent\")\n", "#chart\n", "#`chart.set_xticklabels(chart.get_xticklabels(), rotation=30, horizontalalignment='right')" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "One-Hot-Encoding of class-labels:" ] }, { "cell_type": "code", "execution_count": 10, "metadata": {}, "outputs": [], "source": [ "from sklearn.preprocessing import LabelBinarizer" ] }, { "cell_type": "code", "execution_count": 11, "metadata": {}, "outputs": [], "source": [ "binarizer=LabelBinarizer()\n", "trainlabels=binarizer.fit_transform(trainlabels.values)" ] }, { "cell_type": "code", "execution_count": 12, "metadata": {}, "outputs": [ { "data": { "text/plain": [ "(13084, 7)" ] }, "execution_count": 12, "metadata": {}, "output_type": "execute_result" } ], "source": [ "trainlabels.shape" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "Preprocess test- and validation data in the same way as it has been done for training-data:" ] }, { "cell_type": "code", "execution_count": 13, "metadata": {}, "outputs": [], "source": [ "testfeatures=testdf.copy()\n", "testlabels=testfeatures.pop(\"intent\")\n", "validfeatures=validdf.copy()\n", "validlabels=validfeatures.pop(\"intent\")\n", "\n", "testfeatures=testfeatures.values\n", "validfeatures=validfeatures.values\n", "\n", "testlabels=binarizer.transform(testlabels.values)\n", "validlabels=binarizer.transform(validlabels.values)" ] }, { "cell_type": "markdown", "metadata": { "id": "dX8FtlpGJRE6" }, "source": [ "## Loading models from TensorFlow Hub\n", "\n", "Here you can choose which BERT model you will load from TensorFlow Hub and fine-tune. There are multiple BERT models available.\n", "\n", " - [BERT-Base](https://tfhub.dev/tensorflow/bert_en_uncased_L-12_H-768_A-12/3), [Uncased](https://tfhub.dev/tensorflow/bert_en_uncased_L-12_H-768_A-12/3) and [seven more models](https://tfhub.dev/google/collections/bert/1) with trained weights released by the original BERT authors.\n", " - [Small BERTs](https://tfhub.dev/google/collections/bert/1) have the same general architecture but fewer and/or smaller Transformer blocks, which lets you explore tradeoffs between speed, size and quality.\n", " - [ALBERT](https://tfhub.dev/google/collections/albert/1): four different sizes of \"A Lite BERT\" that reduces model size (but not computation time) by sharing parameters between layers.\n", " - [BERT Experts](https://tfhub.dev/google/collections/experts/bert/1): eight models that all have the BERT-base architecture but offer a choice between different pre-training domains, to align more closely with the target task.\n", " - [Electra](https://tfhub.dev/google/collections/electra/1) has the same architecture as BERT (in three different sizes), but gets pre-trained as a discriminator in a set-up that resembles a Generative Adversarial Network (GAN).\n", " - BERT with Talking-Heads Attention and Gated GELU [[base](https://tfhub.dev/tensorflow/talkheads_ggelu_bert_en_base/1), [large](https://tfhub.dev/tensorflow/talkheads_ggelu_bert_en_large/1)] has two improvements to the core of the Transformer architecture.\n", "\n", "The model documentation on TensorFlow Hub has more details and references to the\n", "research literature. Follow the links above, or click on the [`tfhub.dev`](http://tfhub.dev) URL\n", "printed after the next cell execution.\n", "\n", "The suggestion is to start with a Small BERT (with fewer parameters) since they are faster to fine-tune. If you like a small model but with higher accuracy, ALBERT might be your next option. If you want even better accuracy, choose\n", "one of the classic BERT sizes or their recent refinements like Electra, Talking Heads, or a BERT Expert.\n", "\n", "Aside from the models available below, there are [multiple versions](https://tfhub.dev/google/collections/transformer_encoders_text/1) of the models that are larger and can yield even better accuracy but they are too big to be fine-tuned on a single GPU. You will be able to do that on the [Solve GLUE tasks using BERT on a TPU colab](https://www.tensorflow.org/tutorials/text/solve_glue_tasks_using_bert_on_tpu).\n", "\n", "You'll see in the code below that switching the tfhub.dev URL is enough to try any of these models, because all the differences between them are encapsulated in the SavedModels from TF Hub." ] }, { "cell_type": "code", "execution_count": 14, "metadata": { "execution": { "iopub.execute_input": "2021-01-13T03:08:07.421163Z", "iopub.status.busy": "2021-01-13T03:08:07.420022Z", "iopub.status.idle": "2021-01-13T03:08:07.423061Z", "shell.execute_reply": "2021-01-13T03:08:07.423513Z" }, "id": "y8_ctG55-uTX" }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "BERT model selected : https://tfhub.dev/tensorflow/small_bert/bert_en_uncased_L-8_H-512_A-8/1\n", "Preprocess model auto-selected: https://tfhub.dev/tensorflow/bert_en_uncased_preprocess/2\n" ] } ], "source": [ "bert_model_name = 'small_bert/bert_en_uncased_L-8_H-512_A-8' \n", "map_name_to_handle = {\n", " 'bert_en_uncased_L-12_H-768_A-12':\n", " 'https://tfhub.dev/tensorflow/bert_en_uncased_L-12_H-768_A-12/3',\n", " 'bert_en_cased_L-12_H-768_A-12':\n", " 'https://tfhub.dev/tensorflow/bert_en_cased_L-12_H-768_A-12/3',\n", " 'bert_multi_cased_L-12_H-768_A-12':\n", " 'https://tfhub.dev/tensorflow/bert_multi_cased_L-12_H-768_A-12/3',\n", " 'small_bert/bert_en_uncased_L-2_H-128_A-2':\n", " 'https://tfhub.dev/tensorflow/small_bert/bert_en_uncased_L-2_H-128_A-2/1',\n", " 'small_bert/bert_en_uncased_L-2_H-256_A-4':\n", " 'https://tfhub.dev/tensorflow/small_bert/bert_en_uncased_L-2_H-256_A-4/1',\n", " 'small_bert/bert_en_uncased_L-2_H-512_A-8':\n", " 'https://tfhub.dev/tensorflow/small_bert/bert_en_uncased_L-2_H-512_A-8/1',\n", " 'small_bert/bert_en_uncased_L-2_H-768_A-12':\n", " 'https://tfhub.dev/tensorflow/small_bert/bert_en_uncased_L-2_H-768_A-12/1',\n", " 'small_bert/bert_en_uncased_L-4_H-128_A-2':\n", " 'https://tfhub.dev/tensorflow/small_bert/bert_en_uncased_L-4_H-128_A-2/1',\n", " 'small_bert/bert_en_uncased_L-4_H-256_A-4':\n", " 'https://tfhub.dev/tensorflow/small_bert/bert_en_uncased_L-4_H-256_A-4/1',\n", " 'small_bert/bert_en_uncased_L-4_H-512_A-8':\n", " 'https://tfhub.dev/tensorflow/small_bert/bert_en_uncased_L-4_H-512_A-8/1',\n", " 'small_bert/bert_en_uncased_L-4_H-768_A-12':\n", " 'https://tfhub.dev/tensorflow/small_bert/bert_en_uncased_L-4_H-768_A-12/1',\n", " 'small_bert/bert_en_uncased_L-6_H-128_A-2':\n", " 'https://tfhub.dev/tensorflow/small_bert/bert_en_uncased_L-6_H-128_A-2/1',\n", " 'small_bert/bert_en_uncased_L-6_H-256_A-4':\n", " 'https://tfhub.dev/tensorflow/small_bert/bert_en_uncased_L-6_H-256_A-4/1',\n", " 'small_bert/bert_en_uncased_L-6_H-512_A-8':\n", " 'https://tfhub.dev/tensorflow/small_bert/bert_en_uncased_L-6_H-512_A-8/1',\n", " 'small_bert/bert_en_uncased_L-6_H-768_A-12':\n", " 'https://tfhub.dev/tensorflow/small_bert/bert_en_uncased_L-6_H-768_A-12/1',\n", " 'small_bert/bert_en_uncased_L-8_H-128_A-2':\n", " 'https://tfhub.dev/tensorflow/small_bert/bert_en_uncased_L-8_H-128_A-2/1',\n", " 'small_bert/bert_en_uncased_L-8_H-256_A-4':\n", " 'https://tfhub.dev/tensorflow/small_bert/bert_en_uncased_L-8_H-256_A-4/1',\n", " 'small_bert/bert_en_uncased_L-8_H-512_A-8':\n", " 'https://tfhub.dev/tensorflow/small_bert/bert_en_uncased_L-8_H-512_A-8/1',\n", " 'small_bert/bert_en_uncased_L-8_H-768_A-12':\n", " 'https://tfhub.dev/tensorflow/small_bert/bert_en_uncased_L-8_H-768_A-12/1',\n", " 'small_bert/bert_en_uncased_L-10_H-128_A-2':\n", " 'https://tfhub.dev/tensorflow/small_bert/bert_en_uncased_L-10_H-128_A-2/1',\n", " 'small_bert/bert_en_uncased_L-10_H-256_A-4':\n", " 'https://tfhub.dev/tensorflow/small_bert/bert_en_uncased_L-10_H-256_A-4/1',\n", " 'small_bert/bert_en_uncased_L-10_H-512_A-8':\n", " 'https://tfhub.dev/tensorflow/small_bert/bert_en_uncased_L-10_H-512_A-8/1',\n", " 'small_bert/bert_en_uncased_L-10_H-768_A-12':\n", " 'https://tfhub.dev/tensorflow/small_bert/bert_en_uncased_L-10_H-768_A-12/1',\n", " 'small_bert/bert_en_uncased_L-12_H-128_A-2':\n", " 'https://tfhub.dev/tensorflow/small_bert/bert_en_uncased_L-12_H-128_A-2/1',\n", " 'small_bert/bert_en_uncased_L-12_H-256_A-4':\n", " 'https://tfhub.dev/tensorflow/small_bert/bert_en_uncased_L-12_H-256_A-4/1',\n", " 'small_bert/bert_en_uncased_L-12_H-512_A-8':\n", " 'https://tfhub.dev/tensorflow/small_bert/bert_en_uncased_L-12_H-512_A-8/1',\n", " 'small_bert/bert_en_uncased_L-12_H-768_A-12':\n", " 'https://tfhub.dev/tensorflow/small_bert/bert_en_uncased_L-12_H-768_A-12/1',\n", " 'albert_en_base':\n", " 'https://tfhub.dev/tensorflow/albert_en_base/2',\n", " 'electra_small':\n", " 'https://tfhub.dev/google/electra_small/2',\n", " 'electra_base':\n", " 'https://tfhub.dev/google/electra_base/2',\n", " 'experts_pubmed':\n", " 'https://tfhub.dev/google/experts/bert/pubmed/2',\n", " 'experts_wiki_books':\n", " 'https://tfhub.dev/google/experts/bert/wiki_books/2',\n", " 'talking-heads_base':\n", " 'https://tfhub.dev/tensorflow/talkheads_ggelu_bert_en_base/1',\n", "}\n", "\n", "map_model_to_preprocess = {\n", " 'bert_en_uncased_L-12_H-768_A-12':\n", " 'https://tfhub.dev/tensorflow/bert_en_uncased_preprocess/2',\n", " 'bert_en_cased_L-12_H-768_A-12':\n", " 'https://tfhub.dev/tensorflow/bert_en_cased_preprocess/2',\n", " 'small_bert/bert_en_uncased_L-2_H-128_A-2':\n", " 'https://tfhub.dev/tensorflow/bert_en_uncased_preprocess/2',\n", " 'small_bert/bert_en_uncased_L-2_H-256_A-4':\n", " 'https://tfhub.dev/tensorflow/bert_en_uncased_preprocess/2',\n", " 'small_bert/bert_en_uncased_L-2_H-512_A-8':\n", " 'https://tfhub.dev/tensorflow/bert_en_uncased_preprocess/2',\n", " 'small_bert/bert_en_uncased_L-2_H-768_A-12':\n", " 'https://tfhub.dev/tensorflow/bert_en_uncased_preprocess/2',\n", " 'small_bert/bert_en_uncased_L-4_H-128_A-2':\n", " 'https://tfhub.dev/tensorflow/bert_en_uncased_preprocess/2',\n", " 'small_bert/bert_en_uncased_L-4_H-256_A-4':\n", " 'https://tfhub.dev/tensorflow/bert_en_uncased_preprocess/2',\n", " 'small_bert/bert_en_uncased_L-4_H-512_A-8':\n", " 'https://tfhub.dev/tensorflow/bert_en_uncased_preprocess/2',\n", " 'small_bert/bert_en_uncased_L-4_H-768_A-12':\n", " 'https://tfhub.dev/tensorflow/bert_en_uncased_preprocess/2',\n", " 'small_bert/bert_en_uncased_L-6_H-128_A-2':\n", " 'https://tfhub.dev/tensorflow/bert_en_uncased_preprocess/2',\n", " 'small_bert/bert_en_uncased_L-6_H-256_A-4':\n", " 'https://tfhub.dev/tensorflow/bert_en_uncased_preprocess/2',\n", " 'small_bert/bert_en_uncased_L-6_H-512_A-8':\n", " 'https://tfhub.dev/tensorflow/bert_en_uncased_preprocess/2',\n", " 'small_bert/bert_en_uncased_L-6_H-768_A-12':\n", " 'https://tfhub.dev/tensorflow/bert_en_uncased_preprocess/2',\n", " 'small_bert/bert_en_uncased_L-8_H-128_A-2':\n", " 'https://tfhub.dev/tensorflow/bert_en_uncased_preprocess/2',\n", " 'small_bert/bert_en_uncased_L-8_H-256_A-4':\n", " 'https://tfhub.dev/tensorflow/bert_en_uncased_preprocess/2',\n", " 'small_bert/bert_en_uncased_L-8_H-512_A-8':\n", " 'https://tfhub.dev/tensorflow/bert_en_uncased_preprocess/2',\n", " 'small_bert/bert_en_uncased_L-8_H-768_A-12':\n", " 'https://tfhub.dev/tensorflow/bert_en_uncased_preprocess/2',\n", " 'small_bert/bert_en_uncased_L-10_H-128_A-2':\n", " 'https://tfhub.dev/tensorflow/bert_en_uncased_preprocess/2',\n", " 'small_bert/bert_en_uncased_L-10_H-256_A-4':\n", " 'https://tfhub.dev/tensorflow/bert_en_uncased_preprocess/2',\n", " 'small_bert/bert_en_uncased_L-10_H-512_A-8':\n", " 'https://tfhub.dev/tensorflow/bert_en_uncased_preprocess/2',\n", " 'small_bert/bert_en_uncased_L-10_H-768_A-12':\n", " 'https://tfhub.dev/tensorflow/bert_en_uncased_preprocess/2',\n", " 'small_bert/bert_en_uncased_L-12_H-128_A-2':\n", " 'https://tfhub.dev/tensorflow/bert_en_uncased_preprocess/2',\n", " 'small_bert/bert_en_uncased_L-12_H-256_A-4':\n", " 'https://tfhub.dev/tensorflow/bert_en_uncased_preprocess/2',\n", " 'small_bert/bert_en_uncased_L-12_H-512_A-8':\n", " 'https://tfhub.dev/tensorflow/bert_en_uncased_preprocess/2',\n", " 'small_bert/bert_en_uncased_L-12_H-768_A-12':\n", " 'https://tfhub.dev/tensorflow/bert_en_uncased_preprocess/2',\n", " 'bert_multi_cased_L-12_H-768_A-12':\n", " 'https://tfhub.dev/tensorflow/bert_multi_cased_preprocess/2',\n", " 'albert_en_base':\n", " 'https://tfhub.dev/tensorflow/albert_en_preprocess/2',\n", " 'electra_small':\n", " 'https://tfhub.dev/tensorflow/bert_en_uncased_preprocess/2',\n", " 'electra_base':\n", " 'https://tfhub.dev/tensorflow/bert_en_uncased_preprocess/2',\n", " 'experts_pubmed':\n", " 'https://tfhub.dev/tensorflow/bert_en_uncased_preprocess/2',\n", " 'experts_wiki_books':\n", " 'https://tfhub.dev/tensorflow/bert_en_uncased_preprocess/2',\n", " 'talking-heads_base':\n", " 'https://tfhub.dev/tensorflow/bert_en_uncased_preprocess/2',\n", "}\n", "\n", "tfhub_handle_encoder = map_name_to_handle[bert_model_name]\n", "tfhub_handle_preprocess = map_model_to_preprocess[bert_model_name]\n", "\n", "print(f'BERT model selected : {tfhub_handle_encoder}')\n", "print(f'Preprocess model auto-selected: {tfhub_handle_preprocess}')" ] }, { "cell_type": "markdown", "metadata": { "id": "7WrcxxTRDdHi" }, "source": [ "## The preprocessing model\n", "\n", "Text inputs need to be transformed to numeric token ids and arranged in several Tensors before being input to BERT. TensorFlow Hub provides a matching preprocessing model for each of the BERT models discussed above, which implements this transformation using TF ops from the TF.text library. It is not necessary to run pure Python code outside your TensorFlow model to preprocess text.\n", "\n", "The preprocessing model must be the one referenced by the documentation of the BERT model, which you can read at the URL printed above. For BERT models from the drop-down above, the preprocessing model is selected automatically.\n", "\n", "Note: You will load the preprocessing model into a [hub.KerasLayer](https://www.tensorflow.org/hub/api_docs/python/hub/KerasLayer) to compose your fine-tuned model. This is the preferred API to load a TF2-style SavedModel from TF Hub into a Keras model." ] }, { "cell_type": "code", "execution_count": 15, "metadata": { "execution": { "iopub.execute_input": "2021-01-13T03:08:07.428866Z", "iopub.status.busy": "2021-01-13T03:08:07.427625Z", "iopub.status.idle": "2021-01-13T03:08:10.467605Z", "shell.execute_reply": "2021-01-13T03:08:10.468143Z" }, "id": "0SQi-jWd_jzq" }, "outputs": [], "source": [ "bert_preprocess_model = hub.KerasLayer(tfhub_handle_preprocess)" ] }, { "cell_type": "markdown", "metadata": { "id": "x4naBiEE_cZX" }, "source": [ "Let's try the preprocessing model on some text and see the output:" ] }, { "cell_type": "code", "execution_count": 16, "metadata": {}, "outputs": [ { "data": { "text/plain": [ "array(['listen to westbam alumb allergic on google music'], dtype=object)" ] }, "execution_count": 16, "metadata": {}, "output_type": "execute_result" } ], "source": [ "trainfeatures[0]" ] }, { "cell_type": "code", "execution_count": 17, "metadata": { "execution": { "iopub.execute_input": "2021-01-13T03:08:10.482448Z", "iopub.status.busy": "2021-01-13T03:08:10.478061Z", "iopub.status.idle": "2021-01-13T03:08:10.652900Z", "shell.execute_reply": "2021-01-13T03:08:10.652248Z" }, "id": "r9-zCzJpnuwS" }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Keys : ['input_type_ids', 'input_mask', 'input_word_ids']\n", "Shape : (1, 128)\n", "Word Ids : [ 101 4952 2000 2225 3676 2213 2632 25438 27395 2006 8224 2189]\n", "Input Mask : [1 1 1 1 1 1 1 1 1 1 1 1]\n", "Type Ids : [0 0 0 0 0 0 0 0 0 0 0 0]\n" ] } ], "source": [ "text_test = trainfeatures[0]\n", "text_preprocessed = bert_preprocess_model(text_test)\n", "\n", "print(f'Keys : {list(text_preprocessed.keys())}')\n", "print(f'Shape : {text_preprocessed[\"input_word_ids\"].shape}')\n", "print(f'Word Ids : {text_preprocessed[\"input_word_ids\"][0, :12]}')\n", "print(f'Input Mask : {text_preprocessed[\"input_mask\"][0, :12]}')\n", "print(f'Type Ids : {text_preprocessed[\"input_type_ids\"][0, :12]}')" ] }, { "cell_type": "markdown", "metadata": { "id": "EqL7ihkN_862" }, "source": [ "As can be seen, there are 3 outputs from the preprocessing that a BERT model would use (`input_words_id`, `input_mask` and `input_type_ids`).\n", "\n", "Some other important points:\n", "- The input is truncated to 128 tokens. The number of tokens can be customized and you can see more details on the [Solve GLUE tasks using BERT on a TPU colab](https://www.tensorflow.org/tutorials/text/solve_glue_tasks_using_bert_on_tpu).\n", "- The `input_type_ids` only have one value (0) because this is a single sentence input. For a multiple sentence input, it would have one number for each input.\n", "\n", "Since this text preprocessor is a TensorFlow model, It can be included in your model directly." ] }, { "cell_type": "markdown", "metadata": { "id": "DKnLPSEmtp9i" }, "source": [ "## Using the BERT model\n", "\n", "Before putting BERT into an own model, let's take a look at its outputs. You will load it from TF Hub and see the returned values." ] }, { "cell_type": "code", "execution_count": 18, "metadata": { "execution": { "iopub.execute_input": "2021-01-13T03:08:10.658519Z", "iopub.status.busy": "2021-01-13T03:08:10.657556Z", "iopub.status.idle": "2021-01-13T03:08:19.674983Z", "shell.execute_reply": "2021-01-13T03:08:19.675465Z" }, "id": "tXxYpK8ixL34" }, "outputs": [], "source": [ "bert_model = hub.KerasLayer(tfhub_handle_encoder)" ] }, { "cell_type": "code", "execution_count": 19, "metadata": { "execution": { "iopub.execute_input": "2021-01-13T03:08:19.682552Z", "iopub.status.busy": "2021-01-13T03:08:19.681441Z", "iopub.status.idle": "2021-01-13T03:08:20.297383Z", "shell.execute_reply": "2021-01-13T03:08:20.297932Z" }, "id": "_OoF9mebuSZc" }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Loaded BERT: https://tfhub.dev/tensorflow/small_bert/bert_en_uncased_L-8_H-512_A-8/1\n", "Pooled Outputs Shape:(1, 512)\n", "Pooled Outputs Values:[-0.04969434 -0.16525201 -0.99807066 -0.93279284 -0.6145217 -0.22613084\n", " -0.95588505 -0.50678337 0.29122898 0.2631647 0.7982282 0.49405995]\n", "Sequence Outputs Shape:(1, 128, 512)\n", "Sequence Outputs Values:[[-0.1024768 0.22204846 0.59883934 ... -0.25584042 0.61985433\n", " -0.01822574]\n", " [ 0.4550366 -0.57238305 0.5542101 ... -0.28608793 1.3628979\n", " 0.9131196 ]\n", " [ 0.42473704 0.29045174 0.82693 ... 0.28371704 1.7948036\n", " -0.36674204]\n", " ...\n", " [-0.46153253 0.02829356 0.51673454 ... -0.15035403 1.4651561\n", " 0.6449582 ]\n", " [ 0.7110826 1.0848484 0.66065294 ... 0.4794111 0.723307\n", " -0.08312207]\n", " [ 0.35558882 -0.3890488 0.5101847 ... 0.19970936 0.86474574\n", " 0.12227032]]\n" ] } ], "source": [ "bert_results = bert_model(text_preprocessed)\n", "\n", "print(f'Loaded BERT: {tfhub_handle_encoder}')\n", "print(f'Pooled Outputs Shape:{bert_results[\"pooled_output\"].shape}')\n", "print(f'Pooled Outputs Values:{bert_results[\"pooled_output\"][0, :12]}')\n", "print(f'Sequence Outputs Shape:{bert_results[\"sequence_output\"].shape}')\n", "print(f'Sequence Outputs Values:{bert_results[\"sequence_output\"][0, :12]}')" ] }, { "cell_type": "markdown", "metadata": { "id": "sm61jDrezAll" }, "source": [ "The BERT models return a map with 3 important keys: `pooled_output`, `sequence_output`, `encoder_outputs`:\n", "\n", "- `pooled_output` to represent each input sequence as a whole. The shape is `[batch_size, H]`. You can think of this as an embedding for the entire movie review.\n", "- `sequence_output` represents each input token in the context. The shape is `[batch_size, seq_length, H]`. You can think of this as a contextual embedding for every token in the movie review.\n", "- `encoder_outputs` are the intermediate activations of the `L` Transformer blocks. `outputs[\"encoder_outputs\"][i]` is a Tensor of shape `[batch_size, seq_length, 1024]` with the outputs of the i-th Transformer block, for `0 <= i < L`. The last value of the list is equal to `sequence_output`.\n", "\n", "For the fine-tuning you are going to use the `pooled_output` array." ] }, { "cell_type": "markdown", "metadata": { "id": "pDNKfAXbDnJH" }, "source": [ "## Define your model\n", "\n", "You will create a very simple fine-tuned model, with the preprocessing model, the selected BERT model, one Dense and a Dropout layer.\n", "\n", "Note: for more information about the base model's input and output you can use just follow the model's url for documentation. Here specifically you don't need to worry about it because the preprocessing model will take care of that for you.\n" ] }, { "cell_type": "code", "execution_count": 20, "metadata": { "execution": { "iopub.execute_input": "2021-01-13T03:08:20.306302Z", "iopub.status.busy": "2021-01-13T03:08:20.305016Z", "iopub.status.idle": "2021-01-13T03:08:20.307988Z", "shell.execute_reply": "2021-01-13T03:08:20.307291Z" }, "id": "aksj743St9ga" }, "outputs": [], "source": [ "def build_classifier_model():\n", " text_input = tf.keras.layers.Input(shape=(), dtype=tf.string, name='text')\n", " preprocessing_layer = hub.KerasLayer(tfhub_handle_preprocess, name='preprocessing')\n", " encoder_inputs = preprocessing_layer(text_input)\n", " encoder = hub.KerasLayer(tfhub_handle_encoder, trainable=True, name='BERT_encoder')\n", " outputs = encoder(encoder_inputs)\n", " net = outputs['pooled_output']\n", " net = tf.keras.layers.Dropout(0.1)(net)\n", " net = tf.keras.layers.Dense(7, activation=None, name='classifier')(net)\n", " return tf.keras.Model(text_input, net)" ] }, { "cell_type": "markdown", "metadata": { "id": "Zs4yhFraBuGQ" }, "source": [ "Let's check that the model runs with the output of the preprocessing model." ] }, { "cell_type": "code", "execution_count": 21, "metadata": { "execution": { "iopub.execute_input": "2021-01-13T03:08:20.317706Z", "iopub.status.busy": "2021-01-13T03:08:20.316292Z", "iopub.status.idle": "2021-01-13T03:08:27.279676Z", "shell.execute_reply": "2021-01-13T03:08:27.279042Z" }, "id": "mGMF8AZcB2Zy" }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "tf.Tensor(\n", "[[0.15770487 0.21116826 0.03859028 0.04381749 0.03109054 0.0646299\n", " 0.4529987 ]], shape=(1, 7), dtype=float32)\n" ] } ], "source": [ "classifier_model = build_classifier_model()\n", "bert_raw_result = classifier_model(tf.constant(trainfeatures[0]))\n", "print(tf.keras.activations.softmax(bert_raw_result))" ] }, { "cell_type": "markdown", "metadata": { "id": "ZTUzNV2JE2G3" }, "source": [ "The output is meaningless, of course, because the model has not been trained yet.\n", "\n", "Let's take a look at the model's structure." ] }, { "cell_type": "code", "execution_count": 22, "metadata": {}, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Model: \"model\"\n", "__________________________________________________________________________________________________\n", " Layer (type) Output Shape Param # Connected to \n", "==================================================================================================\n", " text (InputLayer) [(None,)] 0 [] \n", " \n", " preprocessing (KerasLayer) {'input_type_ids': 0 ['text[0][0]'] \n", " (None, 128), \n", " 'input_mask': (Non \n", " e, 128), \n", " 'input_word_ids': \n", " (None, 128)} \n", " \n", " BERT_encoder (KerasLayer) {'encoder_outputs': 41373185 ['preprocessing[0][0]', \n", " [(None, 128, 512), 'preprocessing[0][1]', \n", " (None, 128, 512), 'preprocessing[0][2]'] \n", " (None, 128, 512), \n", " (None, 128, 512), \n", " (None, 128, 512), \n", " (None, 128, 512), \n", " (None, 128, 512), \n", " (None, 128, 512)], \n", " 'default': (None, \n", " 512), \n", " 'sequence_output': \n", " (None, 128, 512), \n", " 'pooled_output': ( \n", " None, 512)} \n", " \n", " dropout (Dropout) (None, 512) 0 ['BERT_encoder[0][9]'] \n", " \n", " classifier (Dense) (None, 7) 3591 ['dropout[0][0]'] \n", " \n", "==================================================================================================\n", "Total params: 41,376,776\n", "Trainable params: 41,376,775\n", "Non-trainable params: 1\n", "__________________________________________________________________________________________________\n" ] } ], "source": [ "classifier_model.summary()" ] }, { "cell_type": "markdown", "metadata": { "id": "WbUWoZMwc302" }, "source": [ "## Model training\n", "\n", "You now have all the pieces to train a model, including the preprocessing module, BERT encoder, data, and classifier." ] }, { "cell_type": "markdown", "metadata": { "id": "WpJ3xcwDT56v" }, "source": [ "Since this is a non-binary classification problem and the model outputs probabilities, you'll use `losses.CategoricalCrossentropy` loss function.\n" ] }, { "cell_type": "code", "execution_count": 23, "metadata": { "execution": { "iopub.execute_input": "2021-01-13T03:08:27.596402Z", "iopub.status.busy": "2021-01-13T03:08:27.595622Z", "iopub.status.idle": "2021-01-13T03:08:27.600436Z", "shell.execute_reply": "2021-01-13T03:08:27.600889Z" }, "id": "OWPOZE-L3AgE" }, "outputs": [], "source": [ "loss = tf.keras.losses.CategoricalCrossentropy(from_logits=True)\n", "metrics = tf.metrics.CategoricalAccuracy()" ] }, { "cell_type": "markdown", "metadata": { "id": "SqlarlpC_v0g" }, "source": [ "### Loading the BERT model and training\n", "\n", "Using the `classifier_model` you created earlier, you can compile the model with the loss, metric and optimizer." ] }, { "cell_type": "code", "execution_count": 24, "metadata": { "execution": { "iopub.execute_input": "2021-01-13T03:08:27.621858Z", "iopub.status.busy": "2021-01-13T03:08:27.621180Z", "iopub.status.idle": "2021-01-13T03:08:27.631397Z", "shell.execute_reply": "2021-01-13T03:08:27.631841Z" }, "id": "-7GPDhR98jsD" }, "outputs": [], "source": [ "epochs=5\n", "optimizer=tf.keras.optimizers.Adam(1e-5)\n", "classifier_model.compile(optimizer=optimizer,\n", " loss=loss,\n", " metrics=metrics)" ] }, { "cell_type": "markdown", "metadata": { "id": "CpBuV5j2cS_b" }, "source": [ "Note: training time will vary depending on the complexity of the BERT model you have selected." ] }, { "cell_type": "code", "execution_count": 25, "metadata": { "execution": { "iopub.execute_input": "2021-01-13T03:08:27.636326Z", "iopub.status.busy": "2021-01-13T03:08:27.635519Z", "iopub.status.idle": "2021-01-13T03:15:50.893395Z", "shell.execute_reply": "2021-01-13T03:15:50.893900Z" }, "id": "HtfDFAnN_Neu", "scrolled": true }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Training model with https://tfhub.dev/tensorflow/small_bert/bert_en_uncased_L-8_H-512_A-8/1\n", "Epoch 1/5\n", " 11/409 [..............................] - ETA: 1:40:36 - loss: 1.9467 - categorical_accuracy: 0.2159" ] } ], "source": [ "print(f'Training model with {tfhub_handle_encoder}')\n", "history = classifier_model.fit(x=trainfeatures,y=trainlabels,\n", " validation_data=(validfeatures,validlabels),\n", " batch_size=32,\n", " epochs=epochs)" ] }, { "cell_type": "markdown", "metadata": { "id": "uBthMlTSV8kn" }, "source": [ "### Evaluate the model\n", "\n", "Let's see how the model performs. Two values will be returned. Loss (a number which represents the error, lower values are better), and accuracy." ] }, { "cell_type": "code", "execution_count": null, "metadata": { "execution": { "iopub.execute_input": "2021-01-13T03:15:50.898967Z", "iopub.status.busy": "2021-01-13T03:15:50.898282Z", "iopub.status.idle": "2021-01-13T03:16:53.613847Z", "shell.execute_reply": "2021-01-13T03:16:53.614285Z" }, "id": "slqB-urBV9sP" }, "outputs": [], "source": [ "loss, accuracy = classifier_model.evaluate(testfeatures,testlabels)\n", "\n", "print(f'Loss: {loss}')\n", "print(f'Accuracy: {accuracy}')" ] }, { "cell_type": "markdown", "metadata": { "id": "uttWpgmSfzq9" }, "source": [ "### Plot the accuracy and loss over time\n", "\n", "Based on the `History` object returned by `model.fit()`. You can plot the training and validation loss for comparison, as well as the training and validation accuracy:" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "execution": { "iopub.execute_input": "2021-01-13T03:16:53.641616Z", "iopub.status.busy": "2021-01-13T03:16:53.638634Z", "iopub.status.idle": "2021-01-13T03:16:53.950276Z", "shell.execute_reply": "2021-01-13T03:16:53.950768Z" }, "id": "fiythcODf0xo" }, "outputs": [], "source": [ "history_dict = history.history\n", "print(history_dict.keys())\n", "\n", "acc = history_dict['categorical_accuracy']\n", "val_acc = history_dict['val_categorical_accuracy']\n", "loss = history_dict['loss']\n", "val_loss = history_dict['val_loss']\n", "\n", "epochs = range(1, len(acc) + 1)\n", "fig = plt.figure(figsize=(10, 8))\n", "fig.tight_layout()\n", "\n", "plt.subplot(2, 1, 1)\n", "# \"bo\" is for \"blue dot\"\n", "plt.plot(epochs, loss, 'r', label='Training loss')\n", "# b is for \"solid blue line\"\n", "plt.plot(epochs, val_loss, 'b', label='Validation loss')\n", "plt.title('Training and validation loss')\n", "plt.grid(True)\n", "# plt.xlabel('Epochs')\n", "plt.ylabel('Loss')\n", "plt.legend()\n", "\n", "plt.subplot(2, 1, 2)\n", "plt.plot(epochs, acc, 'r', label='Training acc')\n", "plt.plot(epochs, val_acc, 'b', label='Validation acc')\n", "plt.title('Training and validation accuracy')\n", "plt.grid(True)\n", "plt.xlabel('Epochs')\n", "plt.ylabel('Accuracy')\n", "plt.legend(loc='lower right')" ] }, { "cell_type": "markdown", "metadata": { "id": "WzJZCo-cf-Jf" }, "source": [ "In this plot, the red lines represents the training loss and accuracy, and the blue lines are the validation loss and accuracy." ] }, { "cell_type": "markdown", "metadata": { "id": "oyTappHTvNCz" }, "source": [ "Classifying arbitrary instructions:" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "execution": { "iopub.execute_input": "2021-01-13T03:17:08.070832Z", "iopub.status.busy": "2021-01-13T03:17:08.068184Z", "iopub.status.idle": "2021-01-13T03:17:08.879352Z", "shell.execute_reply": "2021-01-13T03:17:08.878815Z" }, "id": "VBWzH6exlCPS" }, "outputs": [], "source": [ "def print_my_examples(inputs, results):\n", " result_for_printing = \\\n", " [f'input: {inputs[i]:<30} : estimated intent: {results[i]}'\n", " for i in range(len(inputs))]\n", " print(*result_for_printing, sep='\\n')\n", " print()\n", "\n", "\n", "examples = [\n", " 'play a song from U2', # this is the same sentence tried earlier\n", " 'Will it rain tomorrow',\n", " 'I like to hear greatist hits from beastie boys',\n", " 'I like to book a table for 3 persons',\n", " '5 stars for machines like me'\n", "]\n", "\n", "results = tf.nn.softmax(classifier_model(tf.constant(examples)))" ] }, { "cell_type": "code", "execution_count": null, "metadata": {}, "outputs": [], "source": [ "binarizer.classes_" ] }, { "cell_type": "code", "execution_count": null, "metadata": {}, "outputs": [], "source": [ "intents=binarizer.inverse_transform(results.numpy())" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "execution": { "iopub.execute_input": "2021-01-13T03:17:08.070832Z", "iopub.status.busy": "2021-01-13T03:17:08.068184Z", "iopub.status.idle": "2021-01-13T03:17:08.879352Z", "shell.execute_reply": "2021-01-13T03:17:08.878815Z" }, "id": "VBWzH6exlCPS" }, "outputs": [], "source": [ "print_my_examples(examples, intents)" ] }, { "cell_type": "code", "execution_count": null, "metadata": {}, "outputs": [], "source": [] } ], "metadata": { "accelerator": "GPU", "colab": { "collapsed_sections": [], "name": "classify_text_with_bert.ipynb", "toc_visible": true }, "kernelspec": { "display_name": "Python 3.8.10 ('caesarainl': venv)", "language": "python", "name": "python3" }, "language_info": { "codemirror_mode": { "name": "ipython", "version": 3 }, "file_extension": ".py", "mimetype": "text/x-python", "name": "python", "nbconvert_exporter": "python", "pygments_lexer": "ipython3", "version": "3.8.10" }, "toc": { "base_numbering": 1, "nav_menu": {}, "number_sections": true, "sideBar": true, "skip_h1_title": false, "title_cell": "Table of Contents", "title_sidebar": "Contents", "toc_cell": false, "toc_position": {}, "toc_section_display": true, "toc_window_display": false }, "vscode": { "interpreter": { "hash": "405f94f3dc67f15d7addffc962b8172d0d4960d3524e541166097ab2d7a328e0" } } }, "nbformat": 4, "nbformat_minor": 1 }