先日のシグモイド関数(ロジスティック関数)を用いたtensoflow実装。
end0tknr.hateblo.jp
というより、↓こちらの Chapter2の写経。
github.com
import tensorflow as tf
import numpy as np
import matplotlib.pyplot as plt
from numpy.random import multivariate_normal, permutation
import pandas as pd
from pandas import DataFrame, Series
def make_training_data():
np.random.seed(20160512)
mu0, variance0, n0 = [10, 11], 20, 20
data0 = multivariate_normal(mu0, np.eye(2)*variance0 ,n0)
df0 = DataFrame(data0, columns=['x1','x2'])
df0['t'] = 0
mu1, variance1, n1 = [18, 20], 15, 22
data1 = multivariate_normal(mu1, np.eye(2)*variance1 ,n1)
df1 = DataFrame(data1, columns=['x1','x2'])
df1['t'] = 1
df = pd.concat([df0, df1], ignore_index=True)
train_set = df.reindex(permutation(df.index)).reset_index(drop=True)
train_x = train_set[['x1','x2']].as_matrix()
train_t = train_set['t'].as_matrix().reshape([len(train_set), 1])
return train_x, train_t
def make_predict_func():
x = tf.placeholder(tf.float32, [None, 2])
w = tf.Variable(tf.zeros([2, 1]))
w0 = tf.Variable(tf.zeros([1]))
f = tf.matmul(x, w) + w0
p = tf.sigmoid(f)
return p, w, x, w0
def make_err_func(p):
t = tf.placeholder(tf.float32, [None, 1])
loss = -tf.reduce_sum(t*tf.log(p) + (1-t)*tf.log(1-p))
train_step = tf.train.AdamOptimizer().minimize(loss)
correct_prediction = tf.equal(tf.sign(p-0.5), tf.sign(t-0.5))
accuracy = tf.reduce_mean(tf.cast(correct_prediction, tf.float32))
return loss, t, train_step, accuracy
def main():
train_x, train_t = make_training_data()
p ,w, x, w0 = make_predict_func()
loss, t, train_step, accuracy = make_err_func(p)
sess = tf.Session()
sess.run(tf.initialize_all_variables())
i = 0
for _ in range(30000):
i += 1
sess.run(train_step, feed_dict={x:train_x, t:train_t})
if i % 2000 == 0:
loss_val, acc_val = sess.run(
[loss, accuracy], feed_dict={x:train_x, t:train_t})
print ('itep: %d, loss: %f, accuracy: %f'
% (i, loss_val, acc_val))
w0_val, w_val = sess.run([w0, w])
w0_val, w1_val, w2_val = w0_val[0], w_val[0][0], w_val[1][0]
print "w0:", w0_val, " w1:",w1_val, " w2:",w2_val
if __name__ == '__main__':
main()
↑こう書くと↓こう表示されます
$ ./foo_2.py
itep: 2000, loss: 17.505960, accuracy: 0.857143
itep: 4000, loss: 12.778822, accuracy: 0.928571
itep: 6000, loss: 9.999125, accuracy: 0.928571
itep: 8000, loss: 8.244436, accuracy: 0.976190
itep: 10000, loss: 7.087447, accuracy: 0.952381
itep: 12000, loss: 6.303907, accuracy: 0.952381
itep: 14000, loss: 5.765183, accuracy: 0.952381
itep: 16000, loss: 5.393257, accuracy: 0.952381
itep: 18000, loss: 5.138913, accuracy: 0.952381
itep: 20000, loss: 4.969873, accuracy: 0.952381
itep: 22000, loss: 4.863929, accuracy: 0.952381
itep: 24000, loss: 4.804683, accuracy: 0.952381
itep: 26000, loss: 4.778569, accuracy: 0.952381
itep: 28000, loss: 4.772072, accuracy: 0.952381
itep: 30000, loss: 4.771708, accuracy: 0.952381
w0: -21.0061 w1: 0.849911 w2: 0.621193