ktrain 0.8.0b2

ktrain is a lightweight wrapper for Keras to help train neural networks

ktrain

News and Announcements

• 2020-01-13:
  • ktrain v0.8.x is released and now exposes a simplified interface for text classification with HuggingFace Transformers. See this tutorial notebook for more details.
  • As of v0.8.x, ktrain now uses TensorFlow 2. TensorFlow 1.x is no longer supported. If you're using Google Colab and import tensorflow as tf; print(tf.__version__) shows v1.15 is installed, you must install TensorFlow 2: !pip3 install -q tensorflow_gpu==2.0.
• 2019-12-10:
  • ktrain v0.7.x is released and now uses TensorFlow Keras (i.e., tf.keras) instead of stand-alone Keras. If you're using custom Keras models with ktrain, you must change all keras references to tensorflow.keras. That is, don't import Keras like this: from keras.layers import Dense. Do this instead: from tensorflow.keras.layers import Dense. If you mix calls to tf.keras with Keras, you will experience problems. Supported versions of TensorFlow include 1.14 and 2.0.
• Coming Soon:
  • better support for custom data formats and models

---

Overview

ktrain is a lightweight wrapper for the deep learning library Keras (and other libraries) to help build, train, and deploy neural networks. With only a few lines of code, ktrain allows you to easily and quickly:

• estimate an optimal learning rate for your model given your data using a Learning Rate Finder
• utilize learning rate schedules such as the triangular policy, the 1cycle policy, and SGDR to effectively minimize loss and improve generalization
• employ fast and easy-to-use pre-canned models for text, vision, and graph data:
  • text data:
    • Text Classification: BERT, NBSVM, fastText, GRUs with pretrained word vectors, and other models _{^{[example notebook]}}
    • Sequence Labeling: Bidirectional LSTM-CRF with optional pretrained word embeddings _{^{[example notebook]}}
    • Unsupervised Topic Modeling with LDA _{^{[example notebook]}}
    • Document Similarity with One-Class Learning: given some documents of interest, find and score new documents that are semantically similar to them using One-Class Text Classification _{^{[example notebook]}}
    • Document Recommendation Engine: given text from a sample document, recommend documents that are semantically similar to it from a larger corpus _{^{[example notebook]}}
  • vision data:
    • image classification (e.g., ResNet, Wide ResNet, Inception) _{^{[example notebook]}}
  • graph data:
    • graph node classification with graph neural networks (e.g., GraphSAGE) _{^{[example notebook]}}
• perform multilingual text classification (e.g., Chinese Sentiment Analysis with BERT, Arabic Sentiment Analysis with NBSVM)
• load and preprocess text and image data from a variety of formats
• inspect data points that were misclassified and provide explanations to help improve your model
• leverage a simple prediction API for saving and deploying both models and data-preprocessing steps to make predictions on new raw data

Tutorials

Please see the following tutorial notebooks for a guide on how to use ktrain on your projects:

• Tutorial 1: Introduction
• Tutorial 2: Tuning Learning Rates
• Tutorial 3: Image Classification
• Tutorial 4: Text Classification
• Tutorial 5: Learning from Unlabeled Text Data
• Tutorial 6: Text Sequence Tagging for Named Entity Recognition
• Tutorial 7: Graph Node Classification with Graph Neural Networks
• Tutorial A1: Additional tricks, which covers topics such as previewing data augmentation schemes, inspecting intermediate output of Keras models for debugging, setting global weight decay, and use of built-in and custom callbacks.
• Tutorial A2: Explaining Predictions and Misclassifications
• Tutorial A3: Text Classification with Hugging Face Transformers

Some blog tutorials about ktrain are shown below:

ktrain: A Lightweight Wrapper for Keras to Help Train Neural Networks

BERT Text Classification in 3 Lines of Code

Explainable AI in Practice

Examples

Tasks such as text classification and image classification can be accomplished easily with only a few lines of code.

Example: Text Classification of IMDb Movie Reviews Using BERT

import ktrain
from ktrain import text as txt

# load data
(x_train, y_train), (x_test, y_test), preproc = txt.texts_from_folder('data/aclImdb', maxlen=500, 
                                                                     preprocess_mode='bert',
                                                                     train_test_names=['train', 'test'],
                                                                     classes=['pos', 'neg'])

# load model
model = txt.text_classifier('bert', (x_train, y_train), preproc=preproc)

# wrap model and data in ktrain.Learner object
learner = ktrain.get_learner(model, 
                             train_data=(x_train, y_train), 
                             val_data=(x_test, y_test), 
                             batch_size=6)

# find good learning rate
learner.lr_find()             # briefly simulate training to find good learning rate
learner.lr_plot()             # visually identify best learning rate

# train using 1cycle learning rate schedule for 3 epochs
learner.fit_onecycle(2e-5, 3) 

Example: Classifying Images of Dogs and Cats Using a Pretrained ResNet50 model

import ktrain
from ktrain import vision as vis

# load data
(train_data, val_data, preproc) = vis.images_from_folder(
                                              datadir='data/dogscats',
                                              data_aug = vis.get_data_aug(horizontal_flip=True),
                                              train_test_names=['train', 'valid'], 
                                              target_size=(224,224), color_mode='rgb')

# load model
model = vis.image_classifier('pretrained_resnet50', train_data, val_data, freeze_layers=80)

# wrap model and data in ktrain.Learner object
learner = ktrain.get_learner(model=model, train_data=train_data, val_data=val_data, 
                             workers=8, use_multiprocessing=False, batch_size=64)

# find good learning rate
learner.lr_find()             # briefly simulate training to find good learning rate
learner.lr_plot()             # visually identify best learning rate

# train using triangular policy with ModelCheckpoint and implicit ReduceLROnPlateau and EarlyStopping
learner.autofit(1e-4, checkpoint_folder='/tmp/saved_weights') 

Example: Sequence Labeling for Named Entity Recognition using a randomly initialized Bidirectional LSTM CRF model

import ktrain
from ktrain import text as txt

# load data
(trn, val, preproc) = txt.entities_from_txt('data/ner_dataset.csv',
                                            sentence_column='Sentence #',
                                            word_column='Word',
                                            tag_column='Tag', 
                                            data_format='gmb')

# load model
model = txt.sequence_tagger('bilstm-crf', preproc)

# wrap model and data in ktrain.Learner object
learner = ktrain.get_learner(model, train_data=trn, val_data=val)


# conventional training for 1 epoch using a learning rate of 0.001 (Keras default for Adam optmizer)
learner.fit(1e-3, 1) 

Example: Node Classification on Cora Citation Graph using a GraphSAGE model

import ktrain
from ktrain import graph as gr

# load data with supervision ratio of 10%
(trn, val, preproc)  = gr.graph_nodes_from_csv(
                                               'cora.content', # node attributes/labels
                                               'cora.cites',   # edge list
                                               sample_size=20, 
                                               holdout_pct=None, 
                                               holdout_for_inductive=False,
                                              train_pct=0.1, sep='\t')

# load model
model=gr.graph_node_classifier('graphsage', trn)

# wrap model and data in ktrain.Learner object
learner = ktrain.get_learner(model, train_data=trn, val_data=val, batch_size=64)


# find good learning rate
learner.lr_find(max_epochs=100) # briefly simulate training to find good learning rate
learner.lr_plot()               # visually identify best learning rate

# train using triangular policy with ModelCheckpoint and implicit ReduceLROnPlateau and EarlyStopping
learner.autofit(0.01, checkpoint_folder='/tmp/saved_weights')

Using ktrain on Google Colab? See this simple demo of Multiclass Text Classification with BERT.

Additional examples can be found here.

Installation

Make sure pip is up-to-date with: pip3 install -U pip.

1. Ensure TensorFlow 2 is installed if it is not already

For GPU: pip3 install "tensorflow_gpu>=2.0.0"

For CPU: pip3 install "tensorflow>=2.0.0"

2. Install ktrain: pip3 install ktrain

Some things to note:

• As of v0.8.x, ktrain requires TensorFlow 2. TensorFlow 1.x (1.14, 1.15) is no longer suppoted.
• Since some ktrain dependencies have not yet been migrated to tf.keras in TensorFlow 2 (or may have other issues), ktrain is temporarily using forked versions of some libraries. Specifically, ktrain uses forked versions of the eli5 and stellargraph libraries. If not installed, ktrain will complain when a method or function needing either of these libraries is invoked. To install these forked versions, you can do the following:

pip3 install git+https://github.com/amaiya/eli5@tfkeras_0_10_1
pip3 install git+https://github.com/amaiya/stellargraph@no_tf_dep_082

This code was tested on Ubuntu 18.04 LTS using TensorFlow 2.0 (Keras version 2.2.4-tf).

---

Creator: Arun S. Maiya

Email: arun [at] maiya [dot] net