def simple():
 def build():
  'Builds loss graph.'
  x = tf.get_variable('x', shape=[], dtype=tf.float32, initializer=tf.ones_initializer())
  return tf.square(x, name='x_squared')
 return build

def simple ( ) : def build ( ) : x = tf . get_variable ( 'x' , shape = [ ] , dtype = tf . float32 , initializer = tf . ones_initializer ( ) ) return tf . square ( x , name = 'x_squared' ) return build
simple problem: f(x) = x^2 .