loss.py

import tensorflow as tf

def gol_loss(world_next_probabilities, world_next_target):
  """Calculates loss between 2D Game of Life predictions and targets.

  For a reference on Game of Life, see
  [Wikipedia page](https://en.wikipedia.org/wiki/Conway%27s_Game_of_Life).

  The implementation assumes:
   * 2D square world of fixed size.
   * Edge cells are always dead.

  Args:
    world_next_probabilities: A rank-2 `Tensor` representing probabilities
      that each cell lives.
    targets: A rank-2 `Tensor` representing the targets, that is, whether the
      cell actually lives or not.

  Returns:
    A `float`, the loss value.

  """
  with tf.name_scope("gol_loss"):
    return tf.contrib.losses.log_loss(world_next_probabilities, world_next_target)