# Copyright 2015 Google Inc. 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.
# ==============================================================================

"""Functional tests for BiasAdd."""
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function

import numpy as np
import tensorflow as tf


def GetTestConfigs():
  """Get all the valid tests configs to run.

  Returns:
    all the valid test configs as tuples of data_format and use_gpu.
  """
  test_configs = [("NHWC", False), ("NHWC", True)]
  if tf.test.is_built_with_cuda():
    # "NCHW" format is not currently supported on CPU.
    test_configs += [("NCHW", True)]
  return test_configs


class BiasAddTest(tf.test.TestCase):

  def _npBias(self, inputs, bias):
    assert len(bias.shape) == 1
    print(inputs.shape)
    print(bias.shape)
    assert inputs.shape[-1] == bias.shape[0]
    return inputs + bias.reshape(([1] * (len(inputs.shape) - 1))
                                 + [bias.shape[0]])

  def testNpBias(self):
    self.assertAllClose(np.array([[11, 22, 33], [41, 52, 63]]),
                        self._npBias(np.array([[10, 20, 30], [40, 50, 60]]),
                                     np.array([1, 2, 3])))

  def _testBias(self, np_inputs, np_bias, use_gpu=False):
    np_val = self._npBias(np_inputs, np_bias)
    with self.test_session(use_gpu=use_gpu):
      tf_val = tf.nn.bias_add(np_inputs, np_bias).eval()
    self.assertAllCloseAccordingToType(np_val, tf_val)

  def _NHWCToNCHW(self, np_value):
    # fill the input value to at least 3-dimension
    if np_value.ndim < 3:
      np_value = np.reshape(np_value,
                            (1,) * (3 - np_value.ndim) + np_value.shape)
    # move the last dimension to third-to-last
    np_dim = list(range(np_value.ndim))
    np_dim_new = list(np_dim[0:-3]) + list(np_dim[-1:]) + list(np_dim[-3:-1])
    return np.transpose(np_value, np_dim_new)

  def _NCHWToNHWC(self, np_value):
    assert len(np_value.shape) >= 3
    np_dim = list(range(np_value.ndim))
    # move the third-to-last dimension to the last
    np_dim_new = list(np_dim[0:-3]) + list(np_dim[-2:]) + list(np_dim[-3:-2])
    return np.transpose(np_value, np_dim_new)

  def _testBiasNCHW(self, np_inputs, np_bias, use_gpu):
    np_val = self._npBias(np_inputs, np_bias)
    np_inputs = self._NHWCToNCHW(np_inputs)
    with self.test_session(use_gpu=use_gpu):
      tf_val = tf.nn.bias_add(np_inputs, np_bias, data_format="NCHW").eval()
    tf_val = self._NCHWToNHWC(tf_val)
    self.assertAllCloseAccordingToType(np_val, tf_val)

  def _testAll(self, np_inputs, np_bias):
    self._testBias(np_inputs, np_bias, use_gpu=False)
    if np_inputs.dtype in [np.float16, np.float32, np.float64]:
      self._testBias(np_inputs, np_bias, use_gpu=True)
      if tf.test.is_built_with_cuda():
        self._testBiasNCHW(np_inputs, np_bias, use_gpu=True)

  def testInputDims(self):
    with self.assertRaises(ValueError):
      tf.nn.bias_add([1, 2], [1])

  def testBiasVec(self):
    with self.assertRaises(ValueError):
      tf.nn.bias_add(tf.reshape([1, 2], shape=[1, 2]),
                      tf.reshape([1, 2], shape=[1, 2]))

  def testBiasInputsMatch(self):
    with self.assertRaises(ValueError):
      tf.nn.bias_add(tf.reshape([1, 2], shape=[1, 2]),
                      tf.reshape([1], shape=[1]))

  def testIntTypes(self):
    for t in [np.int8, np.int16, np.int32, np.int64]:
      self._testAll(np.array([[10, 20, 30], [40, 50, 60]]).astype(t),
                    np.array([1, 2, 3]).astype(t))

  def testFloatTypes(self):
    for t in [np.float16, np.float32, np.float64]:
      self._testAll(np.random.rand(4, 3, 3).astype(t),
                    np.random.rand(3).astype(t))

  def _testGradient(self, np_input, bias, dtype, data_format, use_gpu):
    with self.test_session(use_gpu=use_gpu):
      if data_format == "NCHW":
        np_input = self._NHWCToNCHW(np_input)
      input_tensor = tf.constant(np_input, shape=np_input.shape, dtype=dtype)
      bias_tensor = tf.constant(bias, shape=bias.shape, dtype=dtype)
      output_tensor = tf.nn.bias_add(input_tensor, bias_tensor,
                                     data_format=data_format)
      tensor_jacob_t, tensor_jacob_n = tf.test.compute_gradient(
          input_tensor, np_input.shape, output_tensor, np_input.shape)
      bias_jacob_t, bias_jacob_n = tf.test.compute_gradient(
          bias_tensor, bias.shape, output_tensor, np_input.shape)

      if dtype == np.float16:
        # Compare fp16 theoretical gradients to fp32 numerical gradients,
        # since fp16 numerical gradients are too imprecise unless great
        # care is taken with choosing the inputs and the delta. This is
        # a weaker check (in particular, it does not test the op itself,
        # only its gradient), but it's much better than nothing.
        input_tensor = tf.constant(np_input, shape=np_input.shape,
                                   dtype=np.float32)
        bias_tensor = tf.constant(bias, shape=bias.shape, dtype=np.float32)
        output_tensor = tf.nn.bias_add(input_tensor, bias_tensor,
                                       data_format=data_format)
        _, tensor_jacob_n = tf.test.compute_gradient(
            input_tensor, np_input.shape, output_tensor, np_input.shape)
        _, bias_jacob_n = tf.test.compute_gradient(
            bias_tensor, bias.shape, output_tensor, np_input.shape)

      threshold = 2e-3
      if dtype == tf.float64:
        threshold = 1e-10
      self.assertAllClose(tensor_jacob_t, tensor_jacob_n, threshold, threshold)
      self.assertAllClose(bias_jacob_t, bias_jacob_n, threshold, threshold)

  def testGradientTensor(self):
    for (data_format, use_gpu) in GetTestConfigs():
      for dtype in (tf.float16, tf.float32, tf.float64):
        np_input = np.array([1.0, 2.0, 3.0, 4.0, 5.0, 6.0],
                            dtype=dtype.as_numpy_dtype).reshape(3, 2)
        bias = np.array([1.3, 2.4], dtype=dtype.as_numpy_dtype)
        self._testGradient(np_input, bias, dtype, data_format, use_gpu)

  def testGradientTensor4D(self):
    for (data_format, use_gpu) in GetTestConfigs():
      for dtype in (tf.float16, tf.float32, tf.float64):
        np_input = np.arange(1.0, 49.0, dtype=dtype.as_numpy_dtype).reshape(
            [2, 3, 4, 2]).astype(np.float32)
        bias = np.array([1.3, 2.4], dtype=dtype.as_numpy_dtype)
        self._testGradient(np_input, bias, dtype, data_format, use_gpu)


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