Linear Regression in TensorFlow

In [2]:

    

import tensorflow as tf
import numpy
import matplotlib.pyplot as plt
rng = numpy.random


    

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# Parameters
learning_rate = 0.01
training_epochs = 2000
display_step = 50


    

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# Training Data
train_X = numpy.asarray([3.3,4.4,5.5,6.71,6.93,4.168,9.779,6.182,7.59,2.167,7.042,10.791,5.313,7.997,5.654,9.27,3.1])
train_Y = numpy.asarray([1.7,2.76,2.09,3.19,1.694,1.573,3.366,2.596,2.53,1.221,2.827,3.465,1.65,2.904,2.42,2.94,1.3])
n_samples = train_X.shape[0]


    

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# tf Graph Input
X = tf.placeholder("float")
Y = tf.placeholder("float")


    

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# Create Model

# Set model weights
W = tf.Variable(rng.randn(), name="weight")
b = tf.Variable(rng.randn(), name="bias")


    

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# Construct a linear model
activation = tf.add(tf.mul(X, W), b)


    

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# Minimize the squared errors
cost = tf.reduce_sum(tf.pow(activation-Y, 2))/(2*n_samples) #L2 loss
optimizer = tf.train.GradientDescentOptimizer(learning_rate).minimize(cost) #Gradient descent


    

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# Initializing the variables
init = tf.initialize_all_variables()


    

In [22]:

    

# Launch the graph
with tf.Session() as sess:
    sess.run(init)

    # Fit all training data
    for epoch in range(training_epochs):
        for (x, y) in zip(train_X, train_Y):
            sess.run(optimizer, feed_dict={X: x, Y: y})

        #Display logs per epoch step
        if epoch % display_step == 0:
            print "Epoch:", '%04d' % (epoch+1), "cost=", \
                "{:.9f}".format(sess.run(cost, feed_dict={X: train_X, Y:train_Y})), \
                "W=", sess.run(W), "b=", sess.run(b)

    print "Optimization Finished!"
    print "cost=", sess.run(cost, feed_dict={X: train_X, Y: train_Y}), \
          "W=", sess.run(W), "b=", sess.run(b)

    #Graphic display
    plt.plot(train_X, train_Y, 'ro', label='Original data')
    plt.plot(train_X, sess.run(W) * train_X + sess.run(b), label='Fitted line')
    plt.legend()
    plt.show()


    

    




Epoch: 0001 cost= 3.389688730 W= 0.0198441 b= -0.273522
Epoch: 0051 cost= 0.134034902 W= 0.383208 b= -0.159746
Epoch: 0101 cost= 0.127440125 W= 0.375261 b= -0.102578
Epoch: 0151 cost= 0.121607177 W= 0.367787 b= -0.0488099
Epoch: 0201 cost= 0.116448022 W= 0.360758 b= 0.00175997
Epoch: 0251 cost= 0.111884907 W= 0.354146 b= 0.0493223
Epoch: 0301 cost= 0.107848980 W= 0.347928 b= 0.0940558
Epoch: 0351 cost= 0.104279339 W= 0.34208 b= 0.136129
Epoch: 0401 cost= 0.101122171 W= 0.336579 b= 0.1757
Epoch: 0451 cost= 0.098329842 W= 0.331405 b= 0.212917
Epoch: 0501 cost= 0.095860250 W= 0.32654 b= 0.247921
Epoch: 0551 cost= 0.093676031 W= 0.321963 b= 0.280843
Epoch: 0601 cost= 0.091744311 W= 0.317659 b= 0.311807
Epoch: 0651 cost= 0.090035893 W= 0.313611 b= 0.340929
Epoch: 0701 cost= 0.088524953 W= 0.309804 b= 0.36832
Epoch: 0751 cost= 0.087188691 W= 0.306222 b= 0.394082
Epoch: 0801 cost= 0.086007021 W= 0.302854 b= 0.418311
Epoch: 0851 cost= 0.084961981 W= 0.299687 b= 0.441099
Epoch: 0901 cost= 0.084037818 W= 0.296708 b= 0.462532
Epoch: 0951 cost= 0.083220571 W= 0.293905 b= 0.48269
Epoch: 1001 cost= 0.082497880 W= 0.29127 b= 0.50165
Epoch: 1051 cost= 0.081858821 W= 0.288791 b= 0.519481
Epoch: 1101 cost= 0.081293717 W= 0.28646 b= 0.536251
Epoch: 1151 cost= 0.080794014 W= 0.284267 b= 0.552026
Epoch: 1201 cost= 0.080352172 W= 0.282205 b= 0.566861
Epoch: 1251 cost= 0.079961479 W= 0.280265 b= 0.580815
Epoch: 1301 cost= 0.079616025 W= 0.278441 b= 0.593939
Epoch: 1351 cost= 0.079310589 W= 0.276725 b= 0.606284
Epoch: 1401 cost= 0.079040587 W= 0.275111 b= 0.617893
Epoch: 1451 cost= 0.078801893 W= 0.273594 b= 0.62881
Epoch: 1501 cost= 0.078590907 W= 0.272167 b= 0.639077
Epoch: 1551 cost= 0.078404360 W= 0.270824 b= 0.648734
Epoch: 1601 cost= 0.078239456 W= 0.269562 b= 0.657817
Epoch: 1651 cost= 0.078093678 W= 0.268374 b= 0.66636
Epoch: 1701 cost= 0.077964827 W= 0.267257 b= 0.674395
Epoch: 1751 cost= 0.077850945 W= 0.266207 b= 0.681952
Epoch: 1801 cost= 0.077750273 W= 0.265219 b= 0.68906
Epoch: 1851 cost= 0.077661335 W= 0.264289 b= 0.695745
Epoch: 1901 cost= 0.077582702 W= 0.263416 b= 0.702033
Epoch: 1951 cost= 0.077513263 W= 0.262593 b= 0.707947
Optimization Finished!
cost= 0.077453 W= 0.261835 b= 0.713401

In [23]:

    

from IPython.display import Image
Image(filename='linearreg.png')


    

    
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