Twitterで流れていた問題のアレ

kaityo256.py

# https://twitter.com/kaityo256/status/904279527353749509
import tensorflow as tf

a = tf.Variable(0.1)
b = tf.Variable(0.2)
c = tf.Variable(0.3)

result = a / (b + c) + b / (c + a) + c / (a + b)

groundtruth = tf.constant(4.0)

loss = tf.squared_difference(result, groundtruth)

global_step = tf.Variable(0, trainable=False)

opt = tf.train.GradientDescentOptimizer(0.0001)

train_op = opt.minimize(loss, global_step=global_step)

with tf.Session() as sess:
  sess.run(tf.global_variables_initializer())
  while True:
    _, step, value, a_value, b_value, c_value = sess.run([train_op, global_step, result, a, b, c])
    print('%d - a:%f, b:%f, c:%f, result:%f' % (step, a_value, b_value, c_value, value))
    if value == 4.0:
      break

115 - a:-0.006626, b:0.045163, c:0.142721, result:4.000000

自然数の解はないと思ったらちゃんとあった。

https://twitter.com/kaityo256/status/904279898507771905