TensorFlow and Keras: An Overview
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TensorFlow and Keras are popular deep learning frameworks. TensorFlow is an open source library for numerical computation using data flow graphs. It was developed by Google and is widely used for machine learning and deep learning. Keras is a higher-level neural network API that can run on top of TensorFlow. It focuses on user-friendliness, modularization and extensibility. Both frameworks make building and training neural networks easier through modular layers and built-in optimization algorithms.
![Code snippet
import tensorflow as tf
# build a linear model where y = w * x + b
w = tf.Variable([0.2], tf.float32, name='weight')
b = tf.Variable([0.3], tf.float32, name='bias')
X = tf.placeholder(tf.float32, name="X")
Y = tf.placeholder(tf.float32, name='Y')
# the training values for x and y
x = ([2.,3.,4.,5.])
y = ([-1.,-2.,-3.,-4.])
# define the linear model
linear_model = w*X+b
# define the loss function
square_delta = tf.square(linear_model - Y)
loss = tf.reduce_sum(square_delta)
#set the learning rate and training epoch
learning_rate = 0.01
training_epoch = 1000
# optimizer
optimizer = tf.train.GradientDescentOptimizer(learning_rate)
train = optimizer.minimize(loss)
# start a session
init = tf.global_variables_initializer()
with tf.Session() as sess:
sess.run(init)
for i in range(training_epoch):
sess.run(train, feed_dict={X:x,Y:y})
# evaluate training accuracy
curr_w, curr_b, curr_loss = sess.run([w, b, loss], {X:x,Y:y})
print('w: %f b: %f loss: %f '%(curr_w, curr_b, curr_loss))](https://image.slidesharecdn.com/tensorflowkeras-170818142907/85/TensorFlow-and-Keras-An-Overview-16-320.jpg)
![Code-snippet
import numpy as np
from keras.models import Sequential
from keras.layers.core import Activation, Dense
from keras.optimizers import SGD
X = np.array([[0,0],[0,1],[1,0],[1,1]])
y = np.array([[0],[1],[1],[0]])
model = Sequential()
model.add(Dense(2, input_dim=2, activation='sigmoid'))
model.add(Dense(1, activation='sigmoid'))
sgd = SGD(lr=0.1, decay=1e-6, momentum=0.9, nesterov=True)
model.compile(loss='mean_squared_error', optimizer=sgd)
history = model.fit(X, y, nb_epoch=10000, batch_size=4)](https://image.slidesharecdn.com/tensorflowkeras-170818142907/85/TensorFlow-and-Keras-An-Overview-26-320.jpg)
![Keras: Installation
• Theano :
• pip3 install Theano
• CNTK
• $ export CNTK_BINARY_URL=... [choose link here]
• pip3 install $CNTK_BINARY_URL
• TensorFlow :
• $ export TF_BINARY_URL=... [choose link here]
• pip3 install $TF_BINARY_URL
• Keras :
• pip3 install keras
• To enable GPU computing :
• NVidia Cuda
• CuDNN
• CNMeM](https://image.slidesharecdn.com/tensorflowkeras-170818142907/85/TensorFlow-and-Keras-An-Overview-27-320.jpg)
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TensorFlow and Keras: An Overview
- 4. What is TensorFlow? • URL: https://www.tensorflow.org/ • Released under the open source license on November 9, 2015 • Current version 1.2 • Open source software library for numerical computation using data flow graphs • Originally developed by Google Brain Team to conduct machine learning and deep neural networks research • General enough to be applicable in a wide variety of other domains as well • TensorFlow provides an extensive suite of functions and classes that allow users to build various models from scratch.
- 5. Most popular on Github https://github.com/tensorflow/tensorflow
- 6. TensorFlow architecture • Core in C++ • Low overhead • Different front ends for specifying/driving the computation • Python, C++, R and many more
- 7. CPU - GPU • In TensorFlow, the supported device types are CPU and GPU. They are represented as strings. For example: • "/cpu:0": The CPU of your machine. • "/gpu:0": The GPU of your machine, if you have one. • "/gpu:1": The second GPU of your machine, etc.
- 8. What is a Tensor?
- 9. Why it is called TensorFlow? ● TensorFlow is based on computation data flow graph ● TensorFlow separates definition of computations from their execution
- 10. TensorFlow Graph
- 11. Learn Parameters: Optimization ● The Optimizer base class provides methods to compute gradients for a loss and apply gradients to variables. ● A collection of subclasses implement classic optimization algorithms such as GradientDescent and Adagrad. ● TensorFlow provides functions to compute the derivatives for a given TensorFlow computation graph, adding operations to the graph.
- 13. TensorBoard • Visualize your TensorFlow graph • Plot quantitative metrics about the execution of your graph • Show additional data like images that pass through it
- 14. TensorFlow Models https://github.com/tensorflow/models Models • adversarial_crypto: protecting communications with adversarial neural cryptography. • adversarial_text: semi-supervised sequence learning with adversarial training. • attention_ocr: a model for real-world image text extraction. • autoencoder: various autoencoders. • cognitive_mapping_and_planning: implementation of a spatial memory based mapping and planning architecture for visual navigation. • compression: compressing and decompressing images using a pre-trained Residual GRU network. • differential_privacy: privacy-preserving student models from multiple teachers. • domain_adaptation: domain separation networks. • im2txt: image-to-text neural network for image captioning. • inception: deep convolutional networks for computer vision.
- 15. TensorFlow Serving •Flexible, high-performance serving system for machine learning models, designed for production environments. •Easy to deploy new algorithms and experiments, while keeping the same server architecture and APIs
- 16. Code snippet import tensorflow as tf # build a linear model where y = w * x + b w = tf.Variable([0.2], tf.float32, name='weight') b = tf.Variable([0.3], tf.float32, name='bias') X = tf.placeholder(tf.float32, name="X") Y = tf.placeholder(tf.float32, name='Y') # the training values for x and y x = ([2.,3.,4.,5.]) y = ([-1.,-2.,-3.,-4.]) # define the linear model linear_model = w*X+b # define the loss function square_delta = tf.square(linear_model - Y) loss = tf.reduce_sum(square_delta) #set the learning rate and training epoch learning_rate = 0.01 training_epoch = 1000 # optimizer optimizer = tf.train.GradientDescentOptimizer(learning_rate) train = optimizer.minimize(loss) # start a session init = tf.global_variables_initializer() with tf.Session() as sess: sess.run(init) for i in range(training_epoch): sess.run(train, feed_dict={X:x,Y:y}) # evaluate training accuracy curr_w, curr_b, curr_loss = sess.run([w, b, loss], {X:x,Y:y}) print('w: %f b: %f loss: %f '%(curr_w, curr_b, curr_loss))
- 17. TensorFlow: Installation • pip3 install tensorflow or • Anaconda: conda install -c conda-forge tensorflow
- 18. Overview: Keras
- 19. Keras •https://keras.io/ •Minimalist, highly modular neural networks library •Written in Python •Capable of running on top of either TensorFlow/Theano and CNTK •Developed with a focus on enabling fast experimentation
- 20. Guiding Principles •Modularity • A model is understood as a sequence or a graph of standalone, fully-configurable modules that can be plugged together with as little restrictions as possible •Minimalism • Each module should be kept short and simple •Easy extensibility • New modules can be easily added and extended •Python • Supports Python
- 21. General Design •General idea is to based on layers and their input/output • Prepare your inputs and output tensors • Create first layer to handle input tensor • Create output layer to handle targets • Build virtually any model you like in between
- 22. Layers •Keras has a number of pre-built layers. Notable examples include: • Regular dense, MLP type keras.layers.core.Dense(units, activation=None, use_bias=True, kernel_initializer='glorot_uniform', bias_initializer='zeros', kernel_regularizer=None, bias_regularizer=None, activity_regularizer=None, kernel_constraint=None, bias_constraint=None) • Recurrent layers, LTSM, GRU, etc keras.layers.recurrent.Recurrent(return_sequences=False, return_state=False, go_backwards=False, stateful=False, unroll=False, implementation=0)
- 23. Layers • 1D Convolutional layers keras.layers.convolutional.Conv1D(filters, kernel_size, strides=1, padding='valid', dilation_rate=1, activation=None, use_bias=True, kernel_initializer='glorot_uniform', bias_initializer='zeros', kernel_regularizer=None, bias_regularizer=None, activity_regularizer=None, kernel_constraint=None, bias_constraint=None) • 2D Convolutional layers keras.layers.convolutional.Conv2D(filters, kernel_size, strides=(1, 1), padding='valid', data_format=None, dilation_rate=(1, 1), activation=None, use_bias=True, kernel_initializer='glorot_uniform', bias_initializer='zeros', kernel_regularizer=None, bias_regularizer=None, activity_regularizer=None, kernel_constraint=None, bias_constraint=None)
- 24. Why use Keras? •Easy and fast prototyping (through total modularity, minimalism, and extensibility). •Supports both convolutional networks and recurrent networks and combinations of the two. •Supports arbitrary connectivity schemes (including multi-input and multi-output training). •Runs seamlessly on CPU and GPU.
- 25. Keras Code examples •The core data structure of Keras is a model •Model → a way to organize layers Model Sequential Graph
- 26. Code-snippet import numpy as np from keras.models import Sequential from keras.layers.core import Activation, Dense from keras.optimizers import SGD X = np.array([[0,0],[0,1],[1,0],[1,1]]) y = np.array([[0],[1],[1],[0]]) model = Sequential() model.add(Dense(2, input_dim=2, activation='sigmoid')) model.add(Dense(1, activation='sigmoid')) sgd = SGD(lr=0.1, decay=1e-6, momentum=0.9, nesterov=True) model.compile(loss='mean_squared_error', optimizer=sgd) history = model.fit(X, y, nb_epoch=10000, batch_size=4)
- 27. Keras: Installation • Theano : • pip3 install Theano • CNTK • $ export CNTK_BINARY_URL=... [choose link here] • pip3 install $CNTK_BINARY_URL • TensorFlow : • $ export TF_BINARY_URL=... [choose link here] • pip3 install $TF_BINARY_URL • Keras : • pip3 install keras • To enable GPU computing : • NVidia Cuda • CuDNN • CNMeM
- 28. Demo Slides & Codes available from Github: https://github.com/kuanhoong/Magic_DeepLearning