Chapter9_Q12.py

from __future__ import division, print_function, unicode_literals               # Needed for interations/loops to work properly!!!
import os
import tensorflow as tf
import numpy as np
from sklearn.metrics import accuracy_score
from datetime import datetime
from scipy.stats import reciprocal
from sklearn.datasets import make_moons

m = 1000
X_moons, y_moons = make_moons(m, noise=0.1, random_state=42)

# plt.plot(X_moons[y_moons == 1, 0], X_moons[y_moons == 1, 1], 'go', label="Positive")
# plt.plot(X_moons[y_moons == 0, 0], X_moons[y_moons == 0, 1], 'r^', label="Negative")
# plt.legend()
# plt.show()

X_moons_with_bias = np.c_[np.ones((m, 1)), X_moons]

y_moons_column_vector = y_moons.reshape(-1, 1)

test_ratio = 0.2
test_size = int(m * test_ratio)
X_train = X_moons_with_bias[:-test_size]
X_test = X_moons_with_bias[-test_size:]
y_train = y_moons_column_vector[:-test_size]
y_test = y_moons_column_vector[-test_size:]

def random_batch(X_train, y_train, batch_size):
    rnd_indices = np.random.randint(0, len(X_train), batch_size)
    X_batch = X_train[rnd_indices]
    y_batch = y_train[rnd_indices]
    return X_batch, y_batch

X_batch, y_batch = random_batch(X_train, y_train, 5)

n_inputs = 2

X = tf.placeholder(tf.float32, shape=(None, n_inputs + 1), name="X")
y = tf.placeholder(tf.float32, shape=(None, 1), name="y")
theta = tf.Variable(tf.random_uniform([n_inputs + 1, 1], -1.0, 1.0, seed=42), name="theta")
logits = tf.matmul(X, theta, name="logits")
# y_proba = 1 / (1 + tf.exp(-logits))
y_proba = tf.sigmoid(logits)

X_train_enhanced = np.c_[X_train,
                         np.square(X_train[:, 1]),
                         np.square(X_train[:, 2]),
                         X_train[:, 1] ** 3,
                         X_train[:, 2] ** 3]
X_test_enhanced = np.c_[X_test,
                        np.square(X_test[:, 1]),
                        np.square(X_test[:, 2]),
                        X_test[:, 1] ** 3,
                        X_test[:, 2] ** 3]

# epsilon = 1e-7  # to avoid an overflow when computing the log
# loss = -tf.reduce_mean(y * tf.log(y_proba + epsilon) + (1 - y) * tf.log(1 - y_proba + epsilon))
# loss = tf.losses.log_loss(y, y_proba)
#
# learning_rate = 0.01
# optimizer = tf.train.GradientDescentOptimizer(learning_rate=learning_rate)
# training_op = optimizer.minimize(loss)
#
# init = tf.global_variables_initializer()
#
# n_epochs = 1001
# batch_size = 50
# n_batches = int(np.ceil(m / batch_size))
#
# with tf.Session() as sess:
#     sess.run(init)
#
#     for epoch in range(n_epochs):
#         for batch_index in range(n_batches):
#             X_batch, y_batch = random_batch(X_train, y_train, batch_size)
#             sess.run(training_op, feed_dict={X: X_batch, y: y_batch})
#         loss_val = loss.eval({X: X_test, y: y_test})
#         if epoch % 100 == 0:
#             print("Epoch:", epoch, "\tLoss:", loss_val)
#
#     y_proba_val = y_proba.eval(feed_dict={X: X_test, y: y_test})

def logistic_regression(X, y, initializer=None, seed=42, learning_rate=0.01):
    n_inputs_including_bias = int(X.get_shape()[1])
    with tf.name_scope("logistic_regression"):
        with tf.name_scope("model"):
            if initializer is None:
                initializer = tf.random_uniform([n_inputs_including_bias, 1], -1.0, 1.0, seed=seed)
            theta = tf.Variable(initializer, name="theta")
            logits = tf.matmul(X, theta, name="logits")
            y_proba = tf.sigmoid(logits)
        with tf.name_scope("train"):
            loss = tf.losses.log_loss(y, y_proba, scope="loss")
            optimizer = tf.train.GradientDescentOptimizer(learning_rate=learning_rate)
            training_op = optimizer.minimize(loss)
            loss_summary = tf.summary.scalar('log_loss', loss)
        with tf.name_scope("init"):
            init = tf.global_variables_initializer()
        with tf.name_scope("save"):
            saver = tf.train.Saver()
    return y_proba, loss, training_op, loss_summary, init, saver


def log_dir(prefix=""):
    """Function to get the name of the log directory to save the summaries for
    TensorBoard"""
    now = datetime.utcnow().strftime("%Y%m%d%H%M%S")
    root_logdir = "tf_logs"
    if prefix:
        prefix += "-"
    name = prefix + "run-" + now
    return "{}/{}/".format(root_logdir, name)


n_inputs = 2 + 4
logdir = log_dir("logreg")

y_proba, loss, training_op, loss_summary, init, saver = logistic_regression(X, y)

file_writer = tf.summary.FileWriter(logdir, tf.get_default_graph())

n_epochs = 10001
batch_size = 50
n_batches = int(np.ceil(m / batch_size))

checkpoint_path = "/tmp/my_logreg_model.ckpt"
checkpoint_epoch_path = checkpoint_path + ".epoch"
final_model_path = "./my_logreg_model"

with tf.Session() as sess:
    if os.path.isfile(checkpoint_epoch_path):
        # if the checkpoint file exists, restore the model and load the epoch number
        with open(checkpoint_epoch_path, "rb") as f:
            start_epoch = int(f.read())
        print("Training was interrupted. Continuing at epoch", start_epoch)
        saver.restore(sess, checkpoint_path)
    else:
        start_epoch = 0
        sess.run(init)

    for epoch in range(start_epoch, n_epochs):
        for batch_index in range(n_batches):
            X_batch, y_batch = random_batch(X_train_enhanced, y_train, batch_size)
            sess.run(training_op, feed_dict={X: X_batch, y: y_batch})
        loss_val, summary_str = sess.run([loss, loss_summary], feed_dict={X: X_test_enhanced, y: y_test})
        file_writer.add_summary(summary_str, epoch)
        if epoch % 500 == 0:
            print("Epoch:", epoch, "\tLoss:", loss_val)
            saver.save(sess, checkpoint_path)
            with open(checkpoint_epoch_path, "wb") as f:
                f.write(b"%d" % (epoch + 1))

    saver.save(sess, final_model_path)
    y_proba_val = y_proba.eval(feed_dict={X: X_test_enhanced, y: y_test})
    os.remove(checkpoint_epoch_path)

n_search_iterations = 10

for search_iteration in range(n_search_iterations):
    batch_size = np.random.randint(1, 100)
    learning_rate = reciprocal(0.0001, 0.1).rvs(random_state=search_iteration)

    n_inputs = 2 + 4
    logdir = log_dir("logreg")

    print("Iteration", search_iteration)
    print("  logdir:", logdir)
    print("  batch size:", batch_size)
    print("  learning_rate:", learning_rate)
    print("  training: ", end="")

    reset_graph()

    X = tf.placeholder(tf.float32, shape=(None, n_inputs + 1), name="X")
    y = tf.placeholder(tf.float32, shape=(None, 1), name="y")

    y_proba, loss, training_op, loss_summary, init, saver = logistic_regression(
        X, y, learning_rate=learning_rate)

    file_writer = tf.summary.FileWriter(logdir, tf.get_default_graph())

    n_epochs = 10001
    n_batches = int(np.ceil(m / batch_size))

    final_model_path = "./my_logreg_model_%d" % search_iteration

    with tf.Session() as sess:
        sess.run(init)

        for epoch in range(n_epochs):
            for batch_index in range(n_batches):
                X_batch, y_batch = random_batch(X_train_enhanced, y_train, batch_size)
                sess.run(training_op, feed_dict={X: X_batch, y: y_batch})
            loss_val, summary_str = sess.run([loss, loss_summary], feed_dict={X: X_test_enhanced, y: y_test})
            file_writer.add_summary(summary_str, epoch)
            if epoch % 500 == 0:
                print(".", end="")

        saver.save(sess, final_model_path)

        print()
        y_proba_val = y_proba.eval(feed_dict={X: X_test_enhanced, y: y_test})
        y_pred = (y_proba_val >= 0.5)

        print("  precision:", precision_score(y_test, y_pred))
        print("  recall:", recall_score(y_test, y_pred))