# Copyright 2015 The TensorFlow Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ==============================================================================

"""Tests for Adam."""
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function

import numpy as np
import tensorflow as tf


def adam_update_numpy(param, g_t, t, m, v, alpha=0.001, beta1=0.9, beta2=0.999,
                      epsilon=1e-8):
  alpha_t = alpha * np.sqrt(1 - beta2 ** t) / (1 - beta1 ** t)

  m_t = beta1 * m + (1 - beta1) * g_t
  v_t = beta2 * v + (1 - beta2) * g_t * g_t

  param_t = param - alpha_t * m_t / (np.sqrt(v_t) + epsilon)
  return param_t, m_t, v_t


class AdamOptimizerTest(tf.test.TestCase):

  def testSparse(self):
    for dtype in [tf.half, tf.float32, tf.float64]:
      with self.test_session():
        # Initialize variables for numpy implementation.
        m0, v0, m1, v1 = 0.0, 0.0, 0.0, 0.0
        var0_np = np.array([1.0, 2.0], dtype=dtype.as_numpy_dtype)
        grads0_np = np.array([0.1, 0.1], dtype=dtype.as_numpy_dtype)
        var1_np = np.array([3.0, 4.0], dtype=dtype.as_numpy_dtype)
        grads1_np = np.array([0.01, 0.01], dtype=dtype.as_numpy_dtype)

        var0 = tf.Variable(var0_np)
        var1 = tf.Variable(var1_np)
        grads0_np_indices = np.array([0, 1], dtype=np.int32)
        grads0 = tf.IndexedSlices(tf.constant(grads0_np),
                                  tf.constant(grads0_np_indices),
                                  tf.constant([2]))
        grads1_np_indices = np.array([0, 1], dtype=np.int32)
        grads1 = tf.IndexedSlices(tf.constant(grads1_np),
                                  tf.constant(grads1_np_indices),
                                  tf.constant([2]))
        opt = tf.train.AdamOptimizer()
        update = opt.apply_gradients(zip([grads0, grads1], [var0, var1]))
        tf.initialize_all_variables().run()

        # Fetch params to validate initial values
        self.assertAllClose([1.0, 2.0], var0.eval())
        self.assertAllClose([3.0, 4.0], var1.eval())

        beta1_power, beta2_power = opt._get_beta_accumulators()

        # Run 3 steps of Adam
        for t in range(1, 4):
          self.assertAllCloseAccordingToType(0.9 ** t, beta1_power.eval())
          self.assertAllCloseAccordingToType(0.999 ** t, beta2_power.eval())
          update.run()

          var0_np, m0, v0 = adam_update_numpy(var0_np, grads0_np, t, m0, v0)
          var1_np, m1, v1 = adam_update_numpy(var1_np, grads1_np, t, m1, v1)

          # Validate updated params
          self.assertAllCloseAccordingToType(var0_np, var0.eval())
          self.assertAllCloseAccordingToType(var1_np, var1.eval())

  def testBasic(self):
    for dtype in [tf.half, tf.float32, tf.float64]:
      with self.test_session():
        # Initialize variables for numpy implementation.
        m0, v0, m1, v1 = 0.0, 0.0, 0.0, 0.0
        var0_np = np.array([1.0, 2.0], dtype=dtype.as_numpy_dtype)
        grads0_np = np.array([0.1, 0.1], dtype=dtype.as_numpy_dtype)
        var1_np = np.array([3.0, 4.0], dtype=dtype.as_numpy_dtype)
        grads1_np = np.array([0.01, 0.01], dtype=dtype.as_numpy_dtype)

        var0 = tf.Variable(var0_np)
        var1 = tf.Variable(var1_np)
        grads0 = tf.constant(grads0_np)
        grads1 = tf.constant(grads1_np)
        opt = tf.train.AdamOptimizer()
        update = opt.apply_gradients(zip([grads0, grads1], [var0, var1]))
        tf.initialize_all_variables().run()

        # Fetch params to validate initial values
        self.assertAllClose([1.0, 2.0], var0.eval())
        self.assertAllClose([3.0, 4.0], var1.eval())

        beta1_power, beta2_power = opt._get_beta_accumulators()

        # Run 3 steps of Adam
        for t in range(1, 4):
          self.assertAllCloseAccordingToType(0.9 ** t, beta1_power.eval())
          self.assertAllCloseAccordingToType(0.999 ** t, beta2_power.eval())
          update.run()

          var0_np, m0, v0 = adam_update_numpy(var0_np, grads0_np, t, m0, v0)
          var1_np, m1, v1 = adam_update_numpy(var1_np, grads1_np, t, m1, v1)

          # Validate updated params
          self.assertAllCloseAccordingToType(var0_np, var0.eval())
          self.assertAllCloseAccordingToType(var1_np, var1.eval())

  def testTensorLearningRate(self):
    for dtype in [tf.half, tf.float32, tf.float64]:
      with self.test_session():
        # Initialize variables for numpy implementation.
        m0, v0, m1, v1 = 0.0, 0.0, 0.0, 0.0
        var0_np = np.array([1.0, 2.0], dtype=dtype.as_numpy_dtype)
        grads0_np = np.array([0.1, 0.1], dtype=dtype.as_numpy_dtype)
        var1_np = np.array([3.0, 4.0], dtype=dtype.as_numpy_dtype)
        grads1_np = np.array([0.01, 0.01], dtype=dtype.as_numpy_dtype)

        var0 = tf.Variable(var0_np)
        var1 = tf.Variable(var1_np)
        grads0 = tf.constant(grads0_np)
        grads1 = tf.constant(grads1_np)
        opt = tf.train.AdamOptimizer(tf.constant(0.001))
        update = opt.apply_gradients(zip([grads0, grads1], [var0, var1]))
        tf.initialize_all_variables().run()

        # Fetch params to validate initial values
        self.assertAllClose([1.0, 2.0], var0.eval())
        self.assertAllClose([3.0, 4.0], var1.eval())

        beta1_power, beta2_power = opt._get_beta_accumulators()

        # Run 3 steps of Adam
        for t in range(1, 4):
          self.assertAllCloseAccordingToType(0.9 ** t, beta1_power.eval())
          self.assertAllCloseAccordingToType(0.999 ** t, beta2_power.eval())
          update.run()

          var0_np, m0, v0 = adam_update_numpy(var0_np, grads0_np, t, m0, v0)
          var1_np, m1, v1 = adam_update_numpy(var1_np, grads1_np, t, m1, v1)

          # Validate updated params
          self.assertAllCloseAccordingToType(var0_np, var0.eval())
          self.assertAllCloseAccordingToType(var1_np, var1.eval())

  def testSharing(self):
    for dtype in [tf.half, tf.float32, tf.float64]:
      with self.test_session():
        # Initialize variables for numpy implementation.
        m0, v0, m1, v1 = 0.0, 0.0, 0.0, 0.0
        var0_np = np.array([1.0, 2.0], dtype=dtype.as_numpy_dtype)
        grads0_np = np.array([0.1, 0.1], dtype=dtype.as_numpy_dtype)
        var1_np = np.array([3.0, 4.0], dtype=dtype.as_numpy_dtype)
        grads1_np = np.array([0.01, 0.01], dtype=dtype.as_numpy_dtype)

        var0 = tf.Variable(var0_np)
        var1 = tf.Variable(var1_np)
        grads0 = tf.constant(grads0_np)
        grads1 = tf.constant(grads1_np)
        opt = tf.train.AdamOptimizer()
        update1 = opt.apply_gradients(zip([grads0, grads1], [var0, var1]))
        update2 = opt.apply_gradients(zip([grads0, grads1], [var0, var1]))
        tf.initialize_all_variables().run()

        beta1_power, beta2_power = opt._get_beta_accumulators()

        # Fetch params to validate initial values
        self.assertAllClose([1.0, 2.0], var0.eval())
        self.assertAllClose([3.0, 4.0], var1.eval())

        # Run 3 steps of intertwined Adam1 and Adam2.
        for t in range(1, 4):
          self.assertAllCloseAccordingToType(0.9 ** t, beta1_power.eval())
          self.assertAllCloseAccordingToType(0.999 ** t, beta2_power.eval())
          if t % 2 == 0:
            update1.run()
          else:
            update2.run()

          var0_np, m0, v0 = adam_update_numpy(var0_np, grads0_np, t, m0, v0)
          var1_np, m1, v1 = adam_update_numpy(var1_np, grads1_np, t, m1, v1)

          # Validate updated params
          self.assertAllCloseAccordingToType(var0_np, var0.eval())
          self.assertAllCloseAccordingToType(var1_np, var1.eval())

  def testTwoSessions(self):
    optimizer = tf.train.AdamOptimizer()
    g = tf.Graph()
    with g.as_default():
      with tf.Session():
        var0 = tf.Variable(np.array([1.0, 2.0]), name="v0")
        grads0 = tf.constant(np.array([0.1, 0.1]))
        optimizer.apply_gradients([(grads0, var0)])

    gg = tf.Graph()
    with gg.as_default():
      with tf.Session():
        var0 = tf.Variable(np.array([1.0, 2.0]), name="v0")
        grads0 = tf.constant(np.array([0.1, 0.1]))

        # If the optimizer saves any state not keyed by graph the following line
        # fails.
        optimizer.apply_gradients([(grads0, var0)])


if __name__ == "__main__":
  tf.test.main()
