def testSubsampleThreeByThree(self):
   x = array_ops.reshape(math_ops.to_float(math_ops.range(9)), [1, 3, 3, 1])
   x = resnet_utils.subsample(x, 2)
   expected = array_ops.reshape(
       constant_op.constant([0, 2, 6, 8]), [1, 2, 2, 1])
   with self.test_session():
     self.assertAllClose(x.eval(), expected.eval())

 def testSubsampleFourByFour(self):
   x = array_ops.reshape(math_ops.to_float(math_ops.range(16)), [1, 4, 4, 1])
   x = resnet_utils.subsample(x, 2)
   expected = array_ops.reshape(
       constant_op.constant([0, 2, 8, 10]), [1, 2, 2, 1])
   with self.test_session():
     self.assertAllClose(x.eval(), expected.eval())

def bottleneck_hole(inputs,
               depth,
               depth_bottleneck,
               stride,
               rate=2,
               outputs_collections=None,
               scope=None):
  with variable_scope.variable_scope(scope, 'bottleneck_v1', [inputs]) as sc:
    depth_in = utils.last_dimension(inputs.get_shape(), min_rank=4)
    if depth == depth_in:
      shortcut = resnet_utils.subsample(inputs, stride, 'shortcut')
    else:
      shortcut = layers.conv2d(
          inputs,
          depth, [1, 1],
          stride=stride,
          activation_fn=None,
          scope='shortcut')

    residual = layers.conv2d(
        inputs, depth_bottleneck, [1, 1], stride=1, scope='conv1')
    residual = layers_lib.conv2d(residual, depth_bottleneck, [3, 3], stride=1, rate=rate, padding='SAME', scope='conv2')
    residual = layers.conv2d(
        residual, depth, [1, 1], stride=1, activation_fn=None, scope='conv3')

    output = nn_ops.relu(shortcut + residual)

    return utils.collect_named_outputs(outputs_collections, sc.name, output)

 def testAtrousFullyConvolutionalValues(self):
   """Verify dense feature extraction with atrous convolution."""
   nominal_stride = 32
   for output_stride in [4, 8, 16, 32, None]:
     with arg_scope(resnet_utils.resnet_arg_scope()):
       with ops.Graph().as_default():
         with self.test_session() as sess:
           random_seed.set_random_seed(0)
           inputs = create_test_input(2, 81, 81, 3)
           # Dense feature extraction followed by subsampling.
           output, _ = self._resnet_small(
               inputs,
               None,
               is_training=False,
               global_pool=False,
               output_stride=output_stride)
           if output_stride is None:
             factor = 1
           else:
             factor = nominal_stride // output_stride
           output = resnet_utils.subsample(output, factor)
           # Make the two networks use the same weights.
           variable_scope.get_variable_scope().reuse_variables()
           # Feature extraction at the nominal network rate.
           expected, _ = self._resnet_small(
               inputs, None, is_training=False, global_pool=False)
           sess.run(variables.global_variables_initializer())
           self.assertAllClose(
               output.eval(), expected.eval(), atol=1e-4, rtol=1e-4)

def bottleneck(inputs,
               depth,
               depth_bottleneck,
               stride,
               rate=1,
               outputs_collections=None,
               scope=None):
  """Bottleneck residual unit variant with BN before convolutions.

  This is the full preactivation residual unit variant proposed in [2]. See
  Fig. 1(b) of [2] for its definition. Note that we use here the bottleneck
  variant which has an extra bottleneck layer.

  When putting together two consecutive ResNet blocks that use this unit, one
  should use stride = 2 in the last unit of the first block.

  Args:
    inputs: A tensor of size [batch, height, width, channels].
    depth: The depth of the ResNet unit output.
    depth_bottleneck: The depth of the bottleneck layers.
    stride: The ResNet unit's stride. Determines the amount of downsampling of
      the units output compared to its input.
    rate: An integer, rate for atrous convolution.
    outputs_collections: Collection to add the ResNet unit output.
    scope: Optional variable_scope.

  Returns:
    The ResNet unit's output.
  """
  with variable_scope.variable_scope(scope, 'bottleneck_v2', [inputs]) as sc:
    depth_in = utils.last_dimension(inputs.get_shape(), min_rank=4)
    preact = layers.batch_norm(
        inputs, activation_fn=nn_ops.relu, scope='preact')
    if depth == depth_in:
      shortcut = resnet_utils.subsample(inputs, stride, 'shortcut')
    else:
      shortcut = layers_lib.conv2d(
          preact,
          depth, [1, 1],
          stride=stride,
          normalizer_fn=None,
          activation_fn=None,
          scope='shortcut')

    residual = layers_lib.conv2d(
        preact, depth_bottleneck, [1, 1], stride=1, scope='conv1')
    residual = resnet_utils.conv2d_same(
        residual, depth_bottleneck, 3, stride, rate=rate, scope='conv2')
    residual = layers_lib.conv2d(
        residual,
        depth, [1, 1],
        stride=1,
        normalizer_fn=None,
        activation_fn=None,
        scope='conv3')

    output = shortcut + residual

    return utils.collect_named_outputs(outputs_collections, sc.name, output)

def bottleneck(inputs, depth, depth_bottleneck, stride, rate=1, outputs_collections=None, scope=None):
    with tf.variable_scope(scope, 'bottleneck_v1', [inputs]) as sc:
        depth_in = slim.utils.last_dimension(inputs.get_shape(), min_rank=4)
        if depth == depth_in:
            shortcut = resnet_utils.subsample(inputs, stride, 'shortcut')
        else:
            shortcut = slim.conv2d(inputs, depth, [1, 1], stride=stride, activation_fn=None, scope='shortcut')
        residual = slim.conv2d(inputs, depth_bottleneck, [1, 1], stride=1, scope='conv1')
        residual = resnet_utils.conv2d_same(residual, depth_bottleneck, 3, stride, rate=rate, scope='conv2')
        residual = slim.conv2d(residual, depth, [1, 1], stride=1, activation_fn=None, scope='conv3')
        output = tf.nn.relu(shortcut + residual)

    return slim.utils.collect_named_outputs(outputs_collections, sc.original_name_scope, output)

  def _atrousValues(self, bottleneck):
    """Verify the values of dense feature extraction by atrous convolution.

    Make sure that dense feature extraction by stack_blocks_dense() followed by
    subsampling gives identical results to feature extraction at the nominal
    network output stride using the simple self._stack_blocks_nondense() above.

    Args:
      bottleneck: The bottleneck function.
    """
    blocks = [
        resnet_utils.Block('block1', bottleneck, [(4, 1, 1), (4, 1, 2)]),
        resnet_utils.Block('block2', bottleneck, [(8, 2, 1), (8, 2, 2)]),
        resnet_utils.Block('block3', bottleneck, [(16, 4, 1), (16, 4, 2)]),
        resnet_utils.Block('block4', bottleneck, [(32, 8, 1), (32, 8, 1)])
    ]
    nominal_stride = 8

    # Test both odd and even input dimensions.
    height = 30
    width = 31
    with arg_scope(resnet_utils.resnet_arg_scope(is_training=False)):
      for output_stride in [1, 2, 4, 8, None]:
        with ops.Graph().as_default():
          with self.test_session() as sess:
            random_seed.set_random_seed(0)
            inputs = create_test_input(1, height, width, 3)
            # Dense feature extraction followed by subsampling.
            output = resnet_utils.stack_blocks_dense(inputs, blocks,
                                                     output_stride)
            if output_stride is None:
              factor = 1
            else:
              factor = nominal_stride // output_stride

            output = resnet_utils.subsample(output, factor)
            # Make the two networks use the same weights.
            variable_scope.get_variable_scope().reuse_variables()
            # Feature extraction at the nominal network rate.
            expected = self._stack_blocks_nondense(inputs, blocks)
            sess.run(variables.global_variables_initializer())
            output, expected = sess.run([output, expected])
            self.assertAllClose(output, expected, atol=1e-4, rtol=1e-4)

  def testAtrousValuesBottleneck(self):
    """Verify the values of dense feature extraction by atrous convolution.

    Make sure that dense feature extraction by stack_blocks_dense() followed by
    subsampling gives identical results to feature extraction at the nominal
    network output stride using the simple self._stack_blocks_nondense() above.
    """
    block = resnet_v2.resnet_v2_block
    blocks = [
        block('block1', base_depth=1, num_units=2, stride=2),
        block('block2', base_depth=2, num_units=2, stride=2),
        block('block3', base_depth=4, num_units=2, stride=2),
        block('block4', base_depth=8, num_units=2, stride=1),
    ]
    nominal_stride = 8

    # Test both odd and even input dimensions.
    height = 30
    width = 31
    with arg_scope(resnet_utils.resnet_arg_scope()):
      with arg_scope([layers.batch_norm], is_training=False):
        for output_stride in [1, 2, 4, 8, None]:
          with ops.Graph().as_default():
            with self.test_session() as sess:
              random_seed.set_random_seed(0)
              inputs = create_test_input(1, height, width, 3)
              # Dense feature extraction followed by subsampling.
              output = resnet_utils.stack_blocks_dense(inputs, blocks,
                                                       output_stride)
              if output_stride is None:
                factor = 1
              else:
                factor = nominal_stride // output_stride

              output = resnet_utils.subsample(output, factor)
              # Make the two networks use the same weights.
              variable_scope.get_variable_scope().reuse_variables()
              # Feature extraction at the nominal network rate.
              expected = self._stack_blocks_nondense(inputs, blocks)
              sess.run(variables.global_variables_initializer())
              output, expected = sess.run([output, expected])
              self.assertAllClose(output, expected, atol=1e-4, rtol=1e-4)

  def testConv2DSameOdd(self):
    n, n2 = 5, 3

    # Input image.
    x = create_test_input(1, n, n, 1)

    # Convolution kernel.
    w = create_test_input(1, 3, 3, 1)
    w = array_ops.reshape(w, [3, 3, 1, 1])

    variable_scope.get_variable('Conv/weights', initializer=w)
    variable_scope.get_variable('Conv/biases', initializer=array_ops.zeros([1]))
    variable_scope.get_variable_scope().reuse_variables()

    y1 = layers.conv2d(x, 1, [3, 3], stride=1, scope='Conv')
    y1_expected = math_ops.cast([[14, 28, 43, 58, 34],
                                 [28, 48, 66, 84, 46],
                                 [43, 66, 84, 102, 55],
                                 [58, 84, 102, 120, 64],
                                 [34, 46, 55, 64, 30]],
                                dtypes.float32)
    y1_expected = array_ops.reshape(y1_expected, [1, n, n, 1])

    y2 = resnet_utils.subsample(y1, 2)
    y2_expected = math_ops.cast([[14, 43, 34],
                                 [43, 84, 55],
                                 [34, 55, 30]],
                                dtypes.float32)
    y2_expected = array_ops.reshape(y2_expected, [1, n2, n2, 1])

    y3 = resnet_utils.conv2d_same(x, 1, 3, stride=2, scope='Conv')
    y3_expected = y2_expected

    y4 = layers.conv2d(x, 1, [3, 3], stride=2, scope='Conv')
    y4_expected = y2_expected

    with self.cached_session() as sess:
      sess.run(variables.global_variables_initializer())
      self.assertAllClose(y1.eval(), y1_expected.eval())
      self.assertAllClose(y2.eval(), y2_expected.eval())
      self.assertAllClose(y3.eval(), y3_expected.eval())
      self.assertAllClose(y4.eval(), y4_expected.eval())

  def testConv2DSameEven(self):
    n, n2 = 4, 2

    # Input image.
    x = create_test_input(1, n, n, 1)

    # Convolution kernel.
    w = create_test_input(1, 3, 3, 1)
    w = array_ops.reshape(w, [3, 3, 1, 1])

    variable_scope.get_variable('Conv/weights', initializer=w)
    variable_scope.get_variable('Conv/biases', initializer=array_ops.zeros([1]))
    variable_scope.get_variable_scope().reuse_variables()

    y1 = layers.conv2d(x, 1, [3, 3], stride=1, scope='Conv')
    y1_expected = math_ops.to_float([[14, 28, 43, 26], [28, 48, 66, 37],
                                     [43, 66, 84, 46], [26, 37, 46, 22]])
    y1_expected = array_ops.reshape(y1_expected, [1, n, n, 1])

    y2 = resnet_utils.subsample(y1, 2)
    y2_expected = math_ops.to_float([[14, 43], [43, 84]])
    y2_expected = array_ops.reshape(y2_expected, [1, n2, n2, 1])

    y3 = resnet_utils.conv2d_same(x, 1, 3, stride=2, scope='Conv')
    y3_expected = y2_expected

    y4 = layers.conv2d(x, 1, [3, 3], stride=2, scope='Conv')
    y4_expected = math_ops.to_float([[48, 37], [37, 22]])
    y4_expected = array_ops.reshape(y4_expected, [1, n2, n2, 1])

    with self.test_session() as sess:
      sess.run(variables.global_variables_initializer())
      self.assertAllClose(y1.eval(), y1_expected.eval())
      self.assertAllClose(y2.eval(), y2_expected.eval())
      self.assertAllClose(y3.eval(), y3_expected.eval())
      self.assertAllClose(y4.eval(), y4_expected.eval())