Python tensorflow.python.ops.control_flow_ops 模块，Assert() 实例源码

def _assert(cond, ex_type, msg):
    """A polymorphic assert, works with tensors and boolean expressions.
    If `cond` is not a tensor, behave like an ordinary assert statement, except
    that a empty list is returned. If `cond` is a tensor, return a list
    containing a single TensorFlow assert op.
    Args:
      cond: Something evaluates to a boolean value. May be a tensor.
      ex_type: The exception class to use.
      msg: The error message.
    Returns:
      A list, containing at most one assert op.
    """
    if _is_tensor(cond):
        return [control_flow_ops.Assert(cond, [msg])]
    else:
        if not cond:
            raise ex_type(msg)
        else:
            return []

def assert_scalar_int(tensor):
  """Assert `tensor` is 0-D, of type `tf.int32` or `tf.int64`.

  Args:
    tensor: Tensor to test.
  Returns:
    `tensor`, for chaining.
  Raises:
    ValueError: if `tensor` is not 0-D, of type `tf.int32` or `tf.int64`.
  """
  data_type = tensor.dtype
  if data_type.base_dtype not in [dtypes.int32, dtypes.int64]:
    raise ValueError('Unexpected type %s for %s.' % (data_type, tensor.name))
  shape = tensor.get_shape()
  if shape.ndims != 0:
    raise ValueError('Unexpected shape %s for %s.' % (shape, tensor.name))
  return tensor

def _assert_shape_op(expected_shape, actual_tensor):
  """Asserts actual_tensor's shape is expected_shape.

  Args:
    expected_shape: List of integers defining the expected shape, or tensor of
        same.
    actual_tensor: Tensor to test.
  Returns:
    New assert tensor.
  """
  with ops.name_scope('assert_shape', values=[actual_tensor]) as scope:
    actual_shape = array_ops.shape(actual_tensor, name='actual')
    is_shape = _is_shape(expected_shape, actual_tensor, actual_shape)
    return control_flow_ops.Assert(
        is_shape, [
            'Wrong shape for %s [expected] [actual].' % actual_tensor.name,
            expected_shape,
            actual_shape
        ], name=scope)

def assert_integer_form(
    x, data=None, summarize=None, message=None, name="assert_integer_form"):
  """Assert that x has integer components (or floats equal to integers).

  Args:
    x: Numeric `Tensor`
    data: The tensors to print out if the condition is `False`. Defaults to
      error message and first few entries of `x` and `y`.
    summarize: Print this many entries of each tensor.
    message: A string to prefix to the default message.
    name: A name for this operation (optional).

  Returns:
    Op raising `InvalidArgumentError` if round(x) != x.
  """

  message = message or "x has non-integer components"
  x = ops.convert_to_tensor(x, name="x")
  casted_x = math_ops.to_int64(x)
  return check_ops.assert_equal(
      x, math_ops.cast(math_ops.round(casted_x), x.dtype),
      data=data, summarize=summarize, message=message, name=name)

def __init__(self, label_name, weight_column_name, enable_centered_bias,
               head_name, thresholds):
    def loss_fn(logits, labels):
      check_shape_op = control_flow_ops.Assert(
          math_ops.less_equal(array_ops.rank(labels), 2),
          ["labels shape should be either [batch_size, 1] or [batch_size]"])
      with ops.control_dependencies([check_shape_op]):
        labels = array_ops.reshape(
            labels, shape=[array_ops.shape(labels)[0], 1])
      return losses.hinge_loss(logits, labels)

    super(_BinarySvmHead, self).__init__(
        train_loss_fn=loss_fn,
        eval_loss_fn=loss_fn,
        n_classes=2,
        label_name=label_name,
        weight_column_name=weight_column_name,
        enable_centered_bias=enable_centered_bias,
        head_name=head_name,
        thresholds=thresholds)

def _assert(cond, ex_type, msg):
  """A polymorphic assert, works with tensors and boolean expressions.

  If `cond` is not a tensor, behave like an ordinary assert statement, except
  that a empty list is returned. If `cond` is a tensor, return a list
  containing a single TensorFlow assert op.

  Args:
    cond: Something evaluates to a boolean value. May be a tensor.
    ex_type: The exception class to use.
    msg: The error message.

  Returns:
    A list, containing at most one assert op.
  """
  if is_tensor(cond):
    return [logging_ops.Assert(cond, [msg])]
  else:
    if not cond:
      raise ex_type(msg)
    else:
      return []

def _assert(cond, ex_type, msg):
    """A polymorphic assert, works with tensors and boolean expressions.
    If `cond` is not a tensor, behave like an ordinary assert statement, except
    that a empty list is returned. If `cond` is a tensor, return a list
    containing a single TensorFlow assert op.
    Args:
      cond: Something evaluates to a boolean value. May be a tensor.
      ex_type: The exception class to use.
      msg: The error message.
    Returns:
      A list, containing at most one assert op.
    """
    if _is_tensor(cond):
        return [control_flow_ops.Assert(cond, [msg])]
    else:
        if not cond:
            raise ex_type(msg)
        else:
            return []

def _assert(cond, ex_type, msg):
    """A polymorphic assert, works with tensors and boolean expressions.
    If `cond` is not a tensor, behave like an ordinary assert statement, except
    that a empty list is returned. If `cond` is a tensor, return a list
    containing a single TensorFlow assert op.
    Args:
      cond: Something evaluates to a boolean value. May be a tensor.
      ex_type: The exception class to use.
      msg: The error message.
    Returns:
      A list, containing at most one assert op.
    """
    if _is_tensor(cond):
        return [control_flow_ops.Assert(cond, [msg])]
    else:
        if not cond:
            raise ex_type(msg)
        else:
            return []

def _assert(cond, ex_type, msg):
    """A polymorphic assert, works with tensors and boolean expressions.
    If `cond` is not a tensor, behave like an ordinary assert statement, except
    that a empty list is returned. If `cond` is a tensor, return a list
    containing a single TensorFlow assert op.
    Args:
      cond: Something evaluates to a boolean value. May be a tensor.
      ex_type: The exception class to use.
      msg: The error message.
    Returns:
      A list, containing at most one assert op.
    """
    if _is_tensor(cond):
        return [control_flow_ops.Assert(cond, [msg])]
    else:
        if not cond:
            raise ex_type(msg)
        else:
            return []

def assert_scalar_int(tensor, name=None):
  """Assert `tensor` is 0-D, of type `tf.int32` or `tf.int64`.

  Args:
    tensor: `Tensor` to test.
    name: Name of the op and of the new `Tensor` if one is created.
  Returns:
    `tensor`, for chaining.
  Raises:
    ValueError: if `tensor` is not 0-D, of type `tf.int32` or `tf.int64`.
  """
  with ops.name_scope(name, 'assert_scalar_int', [tensor]) as name_scope:
    tensor = ops.convert_to_tensor(tensor)
    data_type = tensor.dtype
    if data_type.base_dtype not in [dtypes.int32, dtypes.int64]:
      raise ValueError('Unexpected type %s for %s.' % (data_type, tensor.name))
    return assert_scalar(tensor, name=name_scope)

def _assert_shape_op(expected_shape, actual_tensor):
  """Asserts actual_tensor's shape is expected_shape.

  Args:
    expected_shape: List of integers defining the expected shape, or tensor of
        same.
    actual_tensor: Tensor to test.
  Returns:
    New assert tensor.
  """
  with ops.name_scope('assert_shape', values=[actual_tensor]) as scope:
    actual_shape = array_ops.shape(actual_tensor, name='actual')
    is_shape = _is_shape(expected_shape, actual_tensor, actual_shape)
    return control_flow_ops.Assert(
        is_shape, [
            'Wrong shape for %s [expected] [actual].' % actual_tensor.name,
            expected_shape,
            actual_shape
        ], name=scope)

def __init__(self, label_name, weight_column_name):

    def loss_fn(logits, target):
      check_shape_op = control_flow_ops.Assert(
          math_ops.less_equal(array_ops.rank(target), 2),
          ["target's shape should be either [batch_size, 1] or [batch_size]"])
      with ops.control_dependencies([check_shape_op]):
        target = array_ops.reshape(
            target, shape=[array_ops.shape(target)[0], 1])
      return loss_ops.hinge_loss(logits, target)

    super(_BinarySvmTargetColumn, self).__init__(
        loss_fn=loss_fn,
        n_classes=2,
        label_name=label_name,
        weight_column_name=weight_column_name)

def random_crop(value, size, seed=None, name=None):
  """Randomly crops a tensor to a given size.

  Slices a shape `size` portion out of `value` at a uniformly chosen offset.
  Requires `value.shape >= size`.

  If a dimension should not be cropped, pass the full size of that dimension.
  For example, RGB images can be cropped with
  `size = [crop_height, crop_width, 3]`.

  Args:
    value: Input tensor to crop.
    size: 1-D tensor with size the rank of `value`.
    seed: Python integer. Used to create a random seed. See
      @{tf.set_random_seed}
      for behavior.
    name: A name for this operation (optional).

  Returns:
    A cropped tensor of the same rank as `value` and shape `size`.
  """
  # TODO(shlens): Implement edge case to guarantee output size dimensions.
  # If size > value.shape, zero pad the result so that it always has shape
  # exactly size.
  with ops.name_scope(name, "random_crop", [value, size]) as name:
    value = ops.convert_to_tensor(value, name="value")
    size = ops.convert_to_tensor(size, dtype=dtypes.int32, name="size")
    shape = array_ops.shape(value)
    check = control_flow_ops.Assert(
        math_ops.reduce_all(shape >= size),
        ["Need value.shape >= size, got ", shape, size],
        summarize=1000)
    shape = control_flow_ops.with_dependencies([check], shape)
    limit = shape - size + 1
    offset = random_uniform(
        array_ops.shape(shape),
        dtype=size.dtype,
        maxval=size.dtype.max,
        seed=seed) % limit
    return array_ops.slice(value, offset, size, name=name)

def _Check3DImage(image, require_static=True):
    """Assert that we are working with properly shaped image.
    Args:
      image: 3-D Tensor of shape [height, width, channels]
        require_static: If `True`, requires that all dimensions of `image` are
        known and non-zero.
    Raises:
      ValueError: if `image.shape` is not a 3-vector.
    Returns:
      An empty list, if `image` has fully defined dimensions. Otherwise, a list
        containing an assert op is returned.
    """
    try:
        image_shape = image.get_shape().with_rank(3)
    except ValueError:
        raise ValueError("'image' must be three-dimensional.")
    if require_static and not image_shape.is_fully_defined():
        raise ValueError("'image' must be fully defined.")
    if any(x == 0 for x in image_shape):
        raise ValueError("all dims of 'image.shape' must be > 0: %s" %
                         image_shape)
    if not image_shape.is_fully_defined():
        return [check_ops.assert_positive(array_ops.shape(image),
                                          ["all dims of 'image.shape' "
                                           "must be > 0."])]
    else:
        return []

def with_same_shape(expected_tensor, tensor):
  """Assert tensors are the same shape, from the same graph.

  Args:
    expected_tensor: Tensor with expected shape.
    tensor: Tensor of actual values.
  Returns:
    Tuple of (actual_tensor, label_tensor), possibly with assert ops added.
  """
  with ops.name_scope('%s/' % tensor.op.name, values=[expected_tensor, tensor]):
    tensor_shape = expected_tensor.get_shape()
    expected_shape = (
        tensor_shape.as_list() if tensor_shape.is_fully_defined()
        else array_ops.shape(expected_tensor, name='expected_shape'))
    return with_shape(expected_shape, tensor)

def _check_multiple_of(value, multiple_of):
  """Checks that value `value` is a non-zero multiple of `multiple_of`.

  Args:
    value: an int32 scalar Tensor.
    multiple_of: an int or int32 scalar Tensor.

  Returns:
    new_value: an int32 scalar Tensor matching `value`, but which includes an
      assertion that `value` is a multiple of `multiple_of`.
  """
  assert isinstance(value, ops.Tensor)
  with ops.control_dependencies([
      control_flow_ops.Assert(
          math_ops.logical_and(
              math_ops.equal(math_ops.mod(value, multiple_of), 0),
              math_ops.not_equal(value, 0)),
          [string_ops.string_join(
              ["Tensor %s should be a multiple of: " % value.name,
               string_ops.as_string(multiple_of),
               ", but saw value: ",
               string_ops.as_string(value),
               ". Consider setting pad=True."])])]):
    new_value = array_ops.identity(
        value, name="multiple_of_checked")
    return new_value

def _check_rank(value, expected_rank):
  """Check the rank of Tensor `value`, via shape inference and assertions.

  Args:
    value: A Tensor, possibly with shape associated shape information.
    expected_rank: int32 scalar (optionally a `Tensor`).

  Returns:
    new_value: A Tensor matching `value`.  Accessing this tensor tests
      assertions on its rank.  If expected_rank is not a `Tensor`, then
      new_value's shape's rank has been set.

  Raises:
    ValueError: if `expected_rank` is not a `Tensor` and the rank of `value`
      is known and is not equal to `expected_rank`.
  """
  assert isinstance(value, ops.Tensor)
  with ops.control_dependencies([
      control_flow_ops.Assert(
          math_ops.equal(expected_rank, array_ops.rank(value)),
          [string_ops.string_join(
              ["Rank of tensor %s should be: " % value.name,
               string_ops.as_string(expected_rank),
               ", shape received:"]),
           array_ops.shape(value)])]):
    new_value = array_ops.identity(value, name="rank_checked")
    if isinstance(expected_rank, ops.Tensor):
      expected_rank_value = tensor_util.constant_value(expected_rank)
      if expected_rank_value is not None:
        expected_rank = int(expected_rank_value)
    if not isinstance(expected_rank, ops.Tensor):
      try:
        new_value.set_shape(new_value.get_shape().with_rank(expected_rank))
      except ValueError as e:
        raise ValueError("Rank check failed for %s: %s"
                         % (value.name, str(e)))
    return new_value

def _log_loss_with_two_classes(logits, target):
  check_shape_op = control_flow_ops.Assert(
      math_ops.less_equal(array_ops.rank(target), 2),
      ["target's shape should be either [batch_size, 1] or [batch_size]"])
  with ops.control_dependencies([check_shape_op]):
    target = array_ops.reshape(target, shape=[array_ops.shape(target)[0], 1])
  return nn.sigmoid_cross_entropy_with_logits(
      logits, math_ops.to_float(target))

def _softmax_cross_entropy_loss(logits, target):
  check_shape_op = control_flow_ops.Assert(
      math_ops.less_equal(array_ops.rank(target), 2),
      ["target's shape should be either [batch_size, 1] or [batch_size]"])
  with ops.control_dependencies([check_shape_op]):
    target = array_ops.reshape(target, shape=[array_ops.shape(target)[0]])
  return nn.sparse_softmax_cross_entropy_with_logits(logits, target)

def _hinge_loss(logits, target):
  check_shape_op = control_flow_ops.Assert(
      math_ops.less_equal(array_ops.rank(target), 2),
      ["target's shape should be either [batch_size, 1] or [batch_size]"])
  with ops.control_dependencies([check_shape_op]):
    target = array_ops.reshape(target, shape=[array_ops.shape(target)[0], 1])
  return losses.hinge_loss(logits, target)

def __init__(self, label_name, weight_column_name):
    def loss_fn(logits, target):
      check_shape_op = control_flow_ops.Assert(
          math_ops.less_equal(array_ops.rank(target), 2),
          ["target's shape should be either [batch_size, 1] or [batch_size]"])
      with ops.control_dependencies([check_shape_op]):
        target = array_ops.reshape(
            target, shape=[array_ops.shape(target)[0], 1])
      return losses.hinge_loss(logits, target)

    super(_BinarySvmTargetColumn, self).__init__(
        loss_fn=loss_fn,
        n_classes=2,
        label_name=label_name,
        weight_column_name=weight_column_name)

def _check_labels_and_scores(boolean_labels, scores, check_shape):
  """Check the rank of labels/scores, return tensor versions."""
  with ops.name_scope('_check_labels_and_scores',
                      values=[boolean_labels, scores]):
    boolean_labels = ops.convert_to_tensor(boolean_labels,
                                           name='boolean_labels')
    scores = ops.convert_to_tensor(scores, name='scores')

    if boolean_labels.dtype != dtypes.bool:
      raise ValueError(
          'Argument boolean_labels should have dtype bool.  Found: %s',
          boolean_labels.dtype)

    if check_shape:
      labels_rank_1 = control_flow_ops.Assert(
          math_ops.equal(1, array_ops.rank(boolean_labels)),
          ['Argument boolean_labels should have rank 1.  Found: ',
           boolean_labels.name, array_ops.shape(boolean_labels)])

      scores_rank_1 = control_flow_ops.Assert(
          math_ops.equal(1, array_ops.rank(scores)),
          ['Argument scores should have rank 1.  Found: ', scores.name,
           array_ops.shape(scores)])

      with ops.control_dependencies([labels_rank_1, scores_rank_1]):
        return boolean_labels, scores
    else:
      return boolean_labels, scores

def kl(dist_a, dist_b, allow_nan=False, name=None):
  """Get the KL-divergence KL(dist_a || dist_b).

  Args:
    dist_a: The first distribution.
    dist_b: The second distribution.
    allow_nan: If `False` (default), a runtime error is raised
      if the KL returns NaN values for any batch entry of the given
      distributions.  If `True`, the KL may return a NaN for the given entry.
    name: (optional) Name scope to use for created operations.

  Returns:
    A Tensor with the batchwise KL-divergence between dist_a and dist_b.

  Raises:
    NotImplementedError: If no KL method is defined for distribution types
      of dist_a and dist_b.
  """
  kl_fn = _DIVERGENCES.get((type(dist_a), type(dist_b)), None)
  if kl_fn is None:
    raise NotImplementedError(
        "No KL(dist_a || dist_b) registered for dist_a type %s and dist_b "
        "type %s" % ((type(dist_a).__name__, type(dist_b).__name__)))
  with ops.name_scope("KullbackLeibler"):
    kl_t = kl_fn(dist_a, dist_b, name=name)
    if allow_nan:
      return kl_t

    # Check KL for NaNs
    kl_t = array_ops.identity(kl_t, name="kl")

    with ops.control_dependencies([
        control_flow_ops.Assert(
            math_ops.logical_not(
                math_ops.reduce_any(math_ops.is_nan(kl_t))),
            ["KL calculation between %s and %s returned NaN values "
             "(and was called with allow_nan=False).  Values:"
             % (dist_a.name, dist_b.name), kl_t])]):
      return array_ops.identity(kl_t, name="checked_kl")

def assert_close(
    x, y, data=None, summarize=None, message=None, name="assert_close"):
  """Assert that that x and y are within machine epsilon of each other.

  Args:
    x: Numeric `Tensor`
    y: Numeric `Tensor`
    data: The tensors to print out if the condition is `False`. Defaults to
      error message and first few entries of `x` and `y`.
    summarize: Print this many entries of each tensor.
    message: A string to prefix to the default message.
    name: A name for this operation (optional).

  Returns:
    Op raising `InvalidArgumentError` if |x - y| > machine epsilon.
  """
  message = message or ""
  x = ops.convert_to_tensor(x, name="x")
  y = ops.convert_to_tensor(y, name="y")

  if x.dtype.is_integer:
    return check_ops.assert_equal(
        x, y, data=data, summarize=summarize, message=message, name=name)

  with ops.name_scope(name, "assert_close", [x, y, data]):
    tol = np.finfo(x.dtype.as_numpy_dtype).resolution
    if data is None:
      data = [
          message,
          "Condition x ~= y did not hold element-wise: x = ", x.name, x, "y = ",
          y.name, y
      ]
    condition = math_ops.reduce_all(math_ops.less_equal(math_ops.abs(x-y), tol))
    return control_flow_ops.Assert(
        condition, data, summarize=summarize)

def assert_scalar_int(tensor):
  """Assert `tensor` is 0-D, of type `tf.int32` or `tf.int64`.

  Args:
    tensor: Tensor to test.
  Returns:
    `tensor`, for chaining.
  Raises:
    ValueError: if `tensor` is not 0-D, of type `tf.int32` or `tf.int64`.
  """
  tensor = ops.convert_to_tensor(tensor)
  data_type = tensor.dtype
  if data_type.base_dtype not in [dtypes.int32, dtypes.int64]:
    raise ValueError('Unexpected type %s for %s.' % (data_type, tensor.name))
  assert_scalar(tensor)

def with_same_shape(expected_tensor, tensor):
  """Assert tensors are the same shape, from the same graph.

  Args:
    expected_tensor: Tensor with expected shape.
    tensor: Tensor of actual values.
  Returns:
    Tuple of (actual_tensor, label_tensor), possibly with assert ops added.
  """
  with ops.name_scope('%s/' % tensor.op.name, values=[expected_tensor, tensor]):
    tensor_shape = expected_tensor.get_shape()
    expected_shape = (
        tensor_shape.as_list() if tensor_shape.is_fully_defined()
        else array_ops.shape(expected_tensor, name='expected_shape'))
    return with_shape(expected_shape, tensor)

def _check_multiple_of(value, multiple_of):
  """Checks that value `value` is a non-zero multiple of `multiple_of`.

  Args:
    value: an int32 scalar Tensor.
    multiple_of: an int or int32 scalar Tensor.

  Returns:
    new_value: an int32 scalar Tensor matching `value`, but which includes an
      assertion that `value` is a multiple of `multiple_of`.
  """
  assert isinstance(value, ops.Tensor)
  with ops.control_dependencies([
      control_flow_ops.Assert(
          math_ops.logical_and(
              math_ops.equal(math_ops.mod(value, multiple_of), 0),
              math_ops.not_equal(value, 0)),
          [string_ops.string_join(
              ["Tensor %s should be a multiple of: " % value.name,
               string_ops.as_string(multiple_of),
               ", but saw value: ",
               string_ops.as_string(value),
               ". Consider setting pad=True."])])]):
    new_value = array_ops.identity(
        value, name="multiple_of_checked")
    return new_value

def _check_rank(value, expected_rank):
  """Check the rank of Tensor `value`, via shape inference and assertions.

  Args:
    value: A Tensor, possibly with shape associated shape information.
    expected_rank: int32 scalar (optionally a `Tensor`).

  Returns:
    new_value: A Tensor matching `value`.  Accessing this tensor tests
      assertions on its rank.  If expected_rank is not a `Tensor`, then
      new_value's shape's rank has been set.

  Raises:
    ValueError: if `expected_rank` is not a `Tensor` and the rank of `value`
      is known and is not equal to `expected_rank`.
  """
  assert isinstance(value, ops.Tensor)
  with ops.control_dependencies([
      control_flow_ops.Assert(
          math_ops.equal(expected_rank, array_ops.rank(value)),
          [string_ops.string_join(
              ["Rank of tensor %s should be: " % value.name,
               string_ops.as_string(expected_rank),
               ", shape received:"]),
           array_ops.shape(value)])]):
    new_value = array_ops.identity(value, name="rank_checked")
    if isinstance(expected_rank, ops.Tensor):
      expected_rank_value = tensor_util.constant_value(expected_rank)
      if expected_rank_value is not None:
        expected_rank = int(expected_rank_value)
    if not isinstance(expected_rank, ops.Tensor):
      try:
        new_value.set_shape(new_value.get_shape().with_rank(expected_rank))
      except ValueError as e:
        raise ValueError("Rank check failed for %s: %s"
                         % (value.name, str(e)))
    return new_value

def __init__(self, label_name, weight_column_name):
    def loss_fn(logits, target):
      check_shape_op = control_flow_ops.Assert(
          math_ops.less_equal(array_ops.rank(target), 2),
          ["target's shape should be either [batch_size, 1] or [batch_size]"])
      with ops.control_dependencies([check_shape_op]):
        target = array_ops.reshape(
            target, shape=[array_ops.shape(target)[0], 1])
      return losses.hinge_loss(logits, target)

    super(_BinarySvmTargetColumn, self).__init__(
        loss_fn=loss_fn,
        n_classes=2,
        label_name=label_name,
        weight_column_name=weight_column_name)

def _check_labels_and_scores(boolean_labels, scores, check_shape):
  """Check the rank of labels/scores, return tensor versions."""
  with ops.name_scope('_check_labels_and_scores',
                      values=[boolean_labels, scores]):
    boolean_labels = ops.convert_to_tensor(boolean_labels,
                                           name='boolean_labels')
    scores = ops.convert_to_tensor(scores, name='scores')

    if boolean_labels.dtype != dtypes.bool:
      raise ValueError(
          'Argument boolean_labels should have dtype bool.  Found: %s',
          boolean_labels.dtype)

    if check_shape:
      labels_rank_1 = control_flow_ops.Assert(
          math_ops.equal(1, array_ops.rank(boolean_labels)),
          ['Argument boolean_labels should have rank 1.  Found: ',
           boolean_labels.name, array_ops.shape(boolean_labels)])

      scores_rank_1 = control_flow_ops.Assert(
          math_ops.equal(1, array_ops.rank(scores)),
          ['Argument scores should have rank 1.  Found: ', scores.name,
           array_ops.shape(scores)])

      with ops.control_dependencies([labels_rank_1, scores_rank_1]):
        return boolean_labels, scores
    else:
      return boolean_labels, scores

def assert_close(
    x, y, data=None, summarize=None, message=None, name="assert_close"):
  """Assert that that x and y are within machine epsilon of each other.

  Args:
    x: Numeric `Tensor`
    y: Numeric `Tensor`
    data: The tensors to print out if the condition is `False`. Defaults to
      error message and first few entries of `x` and `y`.
    summarize: Print this many entries of each tensor.
    message: A string to prefix to the default message.
    name: A name for this operation (optional).

  Returns:
    Op raising `InvalidArgumentError` if |x - y| > machine epsilon.
  """
  message = message or ""
  x = ops.convert_to_tensor(x, name="x")
  y = ops.convert_to_tensor(y, name="y")

  if data is None:
    data = [
        message,
        "Condition x ~= y did not hold element-wise: x = ", x.name, x, "y = ",
        y.name, y
    ]

  if x.dtype.is_integer:
    return check_ops.assert_equal(
        x, y, data=data, summarize=summarize, message=message, name=name)

  with ops.name_scope(name, "assert_close", [x, y, data]):
    tol = np.finfo(x.dtype.as_numpy_dtype).eps
    condition = math_ops.reduce_all(math_ops.less_equal(math_ops.abs(x-y), tol))
    return control_flow_ops.Assert(
        condition, data, summarize=summarize)

def _Check3DImage(image, require_static=True):
  """Assert that we are working with properly shaped image.

  Args:
    image: 3-D Tensor of shape [height, width, channels]
    require_static: If `True`, requires that all dimensions of `image` are
      known and non-zero.

  Raises:
    ValueError: if `image.shape` is not a 3-vector.

  Returns:
    An empty list, if `image` has fully defined dimensions. Otherwise, a list
    containing an assert op is returned.
  """
  try:
    image_shape = image.get_shape().with_rank(3)
  except ValueError:
    raise ValueError("'image' must be three-dimensional.")
  if require_static and not image_shape.is_fully_defined():
    raise ValueError("'image' must be fully defined.")
  if any(x == 0 for x in image_shape):
    raise ValueError("all dims of 'image.shape' must be > 0: %s" %
                     image_shape)
  if not image_shape.is_fully_defined():
    return [check_ops.assert_positive(array_ops.shape(image),
                                      ["all dims of 'image.shape' "
                                       "must be > 0."])]
  else:
    return []

def do_center_crop(value, size, name=None):
    """Randomly crops a tensor to a given size.
    Slices a shape `size` portion out of `value` at a uniformly chosen offset.
    Requires `value.shape >= size`.
    If a dimension should not be cropped, pass the full size of that dimension.
    For example, RGB images can be cropped with
    `size = [crop_height, crop_width, 3]`.
    Args:
        value: Input tensor to crop.
        size: 1-D tensor with size the rank of `value`.
        seed: Python integer. Used to create a random seed. See
            [`set_random_seed`](../../api_docs/python/constant_op.md#set_random_seed)
            for behavior.
        name: A name for this operation (optional).
    Returns:
        A cropped tensor of the same rank as `value` and shape `size`.
    """
    # TODO(shlens): Implement edge case to guarantee output size dimensions.
    # If size > value.shape, zero pad the result so that it always has shape
    # exactly size.
    from tensorflow.python.framework import dtypes
    with ops.op_scope([value, size], name, "center_crop") as name:
        value = ops.convert_to_tensor(value, name="value")
        size = ops.convert_to_tensor(size, dtype=dtypes.int32, name="size")
        shape = array_ops.shape(value)
        check = logging_ops.Assert(
                math_ops.reduce_all(shape >= size),
                ["Need value.shape >= size, got ", shape, size])
        shape = control_flow_ops.with_dependencies([check], shape)
        limit = shape - size + 1
        offset = tf.random_uniform(
                array_ops.shape(shape),
                dtype=size.dtype,
                maxval=size.dtype.max,
                seed=0) % limit
        offset2 = shape // 2 - size // 2
        #import ipdb; ipdb.set_trace()
        return array_ops.slice(value, offset, size, name=name)

def _Check3DImage(image, require_static=True):
    """Assert that we are working with properly shaped image.
    Args:
      image: 3-D Tensor of shape [height, width, channels]
        require_static: If `True`, requires that all dimensions of `image` are
        known and non-zero.
    Raises:
      ValueError: if `image.shape` is not a 3-vector.
    Returns:
      An empty list, if `image` has fully defined dimensions. Otherwise, a list
        containing an assert op is returned.
    """
    try:
        image_shape = image.get_shape().with_rank(3)
    except ValueError:
        raise ValueError("'image' must be three-dimensional.")
    if require_static and not image_shape.is_fully_defined():
        raise ValueError("'image' must be fully defined.")
    if any(x == 0 for x in image_shape):
        raise ValueError("all dims of 'image.shape' must be > 0: %s" %
                         image_shape)
    if not image_shape.is_fully_defined():
        return [check_ops.assert_positive(array_ops.shape(image),
                                          ["all dims of 'image.shape' "
                                           "must be > 0."])]
    else:
        return []

def _Check3DImage(image, require_static=True):
    """Assert that we are working with properly shaped image.
    Args:
      image: 3-D Tensor of shape [height, width, channels]
        require_static: If `True`, requires that all dimensions of `image` are
        known and non-zero.
    Raises:
      ValueError: if `image.shape` is not a 3-vector.
    Returns:
      An empty list, if `image` has fully defined dimensions. Otherwise, a list
        containing an assert op is returned.
    """
    try:
        image_shape = image.get_shape().with_rank(3)
    except ValueError:
        raise ValueError("'image' must be three-dimensional.")
    if require_static and not image_shape.is_fully_defined():
        raise ValueError("'image' must be fully defined.")
    if any(x == 0 for x in image_shape):
        raise ValueError("all dims of 'image.shape' must be > 0: %s" %
                         image_shape)
    if not image_shape.is_fully_defined():
        return [check_ops.assert_positive(array_ops.shape(image),
                                          ["all dims of 'image.shape' "
                                           "must be > 0."])]
    else:
        return []

def _Check3DImage(image, require_static=True):
    """Assert that we are working with properly shaped image.
    Args:
      image: 3-D Tensor of shape [height, width, channels]
        require_static: If `True`, requires that all dimensions of `image` are
        known and non-zero.
    Raises:
      ValueError: if `image.shape` is not a 3-vector.
    Returns:
      An empty list, if `image` has fully defined dimensions. Otherwise, a list
        containing an assert op is returned.
    """
    try:
        image_shape = image.get_shape().with_rank(3)
    except ValueError:
        raise ValueError("'image' must be three-dimensional.")
    if require_static and not image_shape.is_fully_defined():
        raise ValueError("'image' must be fully defined.")
    if any(x == 0 for x in image_shape):
        raise ValueError("all dims of 'image.shape' must be > 0: %s" %
                         image_shape)
    if not image_shape.is_fully_defined():
        return [check_ops.assert_positive(array_ops.shape(image),
                                          ["all dims of 'image.shape' "
                                           "must be > 0."])]
    else:
        return []

def with_same_shape(expected_tensor, tensor):
  """Assert tensors are the same shape, from the same graph.

  Args:
    expected_tensor: Tensor with expected shape.
    tensor: Tensor of actual values.
  Returns:
    Tuple of (actual_tensor, label_tensor), possibly with assert ops added.
  """
  with ops.name_scope('%s/' % tensor.op.name, values=[expected_tensor, tensor]):
    tensor_shape = expected_tensor.get_shape()
    expected_shape = (
        tensor_shape.as_list() if tensor_shape.is_fully_defined()
        else array_ops.shape(expected_tensor, name='expected_shape'))
    return with_shape(expected_shape, tensor)

def test_copy_assert(self):
    ops.reset_default_graph()
    a = constant_op.constant(1)
    b = constant_op.constant(1)
    eq = math_ops.equal(a, b)
    assert_op = control_flow_ops.Assert(eq, [a, b])
    with ops.control_dependencies([assert_op]):
      _ = math_ops.add(a, b)
    sgv = ge.make_view([assert_op, eq.op, a.op, b.op])
    copier = ge.Transformer()
    _, info = copier(sgv, sgv.graph, "", "")
    new_assert_op = info.transformed(assert_op)
    self.assertIsNotNone(new_assert_op)

def _assert_labels_rank(labels):
  return control_flow_ops.Assert(
      math_ops.less_equal(array_ops.rank(labels), 2),
      ("labels shape should be either [batch_size, 1] or [batch_size]",))

def _check_labels_and_scores(boolean_labels, scores, check_shape):
  """Check the rank of labels/scores, return tensor versions."""
  with ops.name_scope('_check_labels_and_scores',
                      values=[boolean_labels, scores]):
    boolean_labels = ops.convert_to_tensor(boolean_labels,
                                           name='boolean_labels')
    scores = ops.convert_to_tensor(scores, name='scores')

    if boolean_labels.dtype != dtypes.bool:
      raise ValueError(
          'Argument boolean_labels should have dtype bool.  Found: %s',
          boolean_labels.dtype)

    if check_shape:
      labels_rank_1 = control_flow_ops.Assert(
          math_ops.equal(1, array_ops.rank(boolean_labels)),
          ['Argument boolean_labels should have rank 1.  Found: ',
           boolean_labels.name, array_ops.shape(boolean_labels)])

      scores_rank_1 = control_flow_ops.Assert(
          math_ops.equal(1, array_ops.rank(scores)),
          ['Argument scores should have rank 1.  Found: ', scores.name,
           array_ops.shape(scores)])

      with ops.control_dependencies([labels_rank_1, scores_rank_1]):
        return boolean_labels, scores
    else:
      return boolean_labels, scores

def assert_close(
    x, y, data=None, summarize=None, message=None, name="assert_close"):
  """Assert that that x and y are within machine epsilon of each other.

  Args:
    x: Numeric `Tensor`
    y: Numeric `Tensor`
    data: The tensors to print out if the condition is `False`. Defaults to
      error message and first few entries of `x` and `y`.
    summarize: Print this many entries of each tensor.
    message: A string to prefix to the default message.
    name: A name for this operation (optional).

  Returns:
    Op raising `InvalidArgumentError` if |x - y| > machine epsilon.
  """
  message = message or ""
  x = ops.convert_to_tensor(x, name="x")
  y = ops.convert_to_tensor(y, name="y")

  if data is None:
    data = [
        message,
        "Condition x ~= y did not hold element-wise: x = ", x.name, x, "y = ",
        y.name, y
    ]

  if x.dtype.is_integer:
    return check_ops.assert_equal(
        x, y, data=data, summarize=summarize, message=message, name=name)

  with ops.name_scope(name, "assert_close", [x, y, data]):
    tol = np.finfo(x.dtype.as_numpy_dtype).eps
    condition = math_ops.reduce_all(math_ops.less_equal(math_ops.abs(x-y), tol))
    return control_flow_ops.Assert(
        condition, data, summarize=summarize)

def _padding(sequences, num_unroll):
  """For a dictionary of sequences, pads tensors to a multiple of `num_unroll`.

  Args:
    sequences: dictionary with `Tensor` values.
    num_unroll: int specifying to what multiple to pad sequences to.
  Returns:
    length: Scalar `Tensor` of dimension 0 of all the values in sequences.
    padded_sequence: Dictionary of sequences that are padded to a multiple of
      `num_unroll`.
  Raises:
    ValueError: If `num_unroll` not an int or sequences not a dictionary from
                string to `Tensor`.
  """
  if not isinstance(num_unroll, numbers.Integral):
    raise ValueError("Unsupported num_unroll expected int, got: %s" %
                     str(num_unroll))
  if not isinstance(sequences, dict):
    raise TypeError("Unsupported sequences expected dict, got: %s" %
                    str(sequences))
  for key, value in sequences.items():
    if not isinstance(key, six.string_types):
      raise TypeError("Unsupported sequences key expected string, got: %s" %
                      str(key))
  if not sequences:
    return 0, {}

  sequences_dict = {}
  for key, value in sequences.items():
    sequences_dict[key] = ops.convert_to_tensor(value)

  lengths = [array_ops.shape(value)[0] for value in sequences_dict.values()]
  length = lengths[0]
  all_lengths_equal = [
      control_flow_ops.Assert(
          math_ops.equal(l, length), [string_ops.string_join(
              ["All sequence lengths must match, but received lengths: ",
               string_ops.as_string(lengths)])])
      for l in lengths]

  length = control_flow_ops.with_dependencies(all_lengths_equal, length)
  unroll = array_ops.constant(num_unroll)
  padded_length = length + ((unroll - (length % unroll)) % unroll)
  padded_sequences = {}
  for key, value in sequences_dict.items():
    # 1. create shape of paddings
    # first dimension of value will be increased by num_paddings to
    # padded_length
    num_paddings = [padded_length - array_ops.shape(value)[0]]
    # the shape of the paddings that we concat with the original value will be
    # [num_paddings, tf.shape(value)[1], tf.shape(value)[2], ...,
    #  tf.shape(value)[tf.rank(value) - 1])]
    padding_shape = array_ops.concat(0, (
        num_paddings, array_ops.shape(value)[1:]))
    # 2. fill padding shape with dummies
    dummy = array_ops.constant("" if value.dtype == dtypes.string else 0,
                               dtype=value.dtype)
    paddings = array_ops.fill(dims=padding_shape, value=dummy)
    # 3. concat values with paddings
    padded_sequences[key] = array_ops.concat(0, [value, paddings])
  return length, padded_sequences

def _check_shape(value, expected_shape):
  """Check the shape of Tensor `value`, via shape inference and assertions.

  Args:
    value: A Tensor, possibly with shape associated shape information.
    expected_shape: a `TensorShape`, list of `int32`, or a vector `Tensor`.

  Returns:
    new_value: A Tensor matching `value`.  Accessing this tensor tests
      assertions on its shape.  If expected_shape is not a `Tensor`, then
      new_value's shape has been set.

  Raises:
    ValueError: if `expected_shape` is not a `Tensor` and the shape of `value`
      is known and is not equal to `expected_shape`.
  """
  assert isinstance(value, ops.Tensor)
  if isinstance(expected_shape, tensor_shape.TensorShape):
    expected_shape = expected_shape.as_list()
  if isinstance(expected_shape, ops.Tensor):
    expected_shape_value = tensor_util.constant_value(expected_shape)
    if expected_shape_value is not None:
      expected_shape = [int(d) for d in expected_shape_value]
  if isinstance(expected_shape, ops.Tensor):
    value = _check_rank(value, array_ops.size(expected_shape))
  else:
    value = _check_rank(value, len(expected_shape))
  with ops.control_dependencies([
      control_flow_ops.Assert(
          math_ops.reduce_all(math_ops.equal(expected_shape, array_ops.shape(
              value))), [string_ops.string_join([
                  "Shape of tensor %s should be: " % value.name,
                  string_ops.as_string(expected_shape), ", shape received: ",
                  string_ops.as_string(array_ops.shape(value))
              ])])
  ]):
    new_value = array_ops.identity(value, name="shape_checked")
    if not isinstance(expected_shape, ops.Tensor):
      try:
        new_value.set_shape(new_value.get_shape().merge_with(expected_shape))
      except ValueError as e:
        raise ValueError("Shape check failed for %s: %s"
                         % (value.name, str(e)))
    return new_value

def _padding(sequences, num_unroll):
  """For a dictionary of sequences, pads tensors to a multiple of `num_unroll`.

  Args:
    sequences: dictionary with `Tensor` values.
    num_unroll: int specifying to what multiple to pad sequences to.
  Returns:
    length: Scalar `Tensor` of dimension 0 of all the values in sequences.
    padded_sequence: Dictionary of sequences that are padded to a multiple of
      `num_unroll`.
  Raises:
    ValueError: If `num_unroll` not an int or sequences not a dictionary from
                string to `Tensor`.
  """
  if not isinstance(num_unroll, numbers.Integral):
    raise ValueError("Unsupported num_unroll expected int, got: %s" %
                     str(num_unroll))
  if not isinstance(sequences, dict):
    raise TypeError("Unsupported sequences expected dict, got: %s" %
                    str(sequences))
  for key, value in sequences.items():
    if not isinstance(key, six.string_types):
      raise TypeError("Unsupported sequences key expected string, got: %s" %
                      str(key))
  if not sequences:
    return 0, {}

  sequences_dict = {}
  for key, value in sequences.items():
    sequences_dict[key] = ops.convert_to_tensor(value)

  lengths = [array_ops.shape(value)[0] for value in sequences_dict.values()]
  length = lengths[0]
  all_lengths_equal = [
      control_flow_ops.Assert(
          math_ops.equal(l, length), [string_ops.string_join(
              ["All sequence lengths must match, but received lengths: ",
               string_ops.as_string(lengths)])])
      for l in lengths]

  length = control_flow_ops.with_dependencies(all_lengths_equal, length)
  unroll = array_ops.constant(num_unroll)
  padded_length = length + ((unroll - (length % unroll)) % unroll)
  padded_sequences = {}
  for key, value in sequences_dict.items():
    # 1. create shape of paddings
    # first dimension of value will be increased by num_paddings to
    # padded_length
    num_paddings = [padded_length - array_ops.shape(value)[0]]
    # the shape of the paddings that we concat with the original value will be
    # [num_paddings, tf.shape(value)[1], tf.shape(value)[2], ...,
    #  tf.shape(value)[tf.rank(value) - 1])]
    padding_shape = array_ops.concat(0, (
        num_paddings, array_ops.shape(value)[1:]))
    # 2. fill padding shape with dummies
    dummy = array_ops.constant("" if value.dtype == dtypes.string else 0,
                               dtype=value.dtype)
    paddings = array_ops.fill(dims=padding_shape, value=dummy)
    # 3. concat values with paddings
    padded_sequences[key] = array_ops.concat(0, [value, paddings])
  return length, padded_sequences

def kl(dist_a, dist_b, allow_nan=False, name=None):
  """Get the KL-divergence KL(dist_a || dist_b).

  If there is no KL method registered specifically for `type(dist_a)` and
  `type(dist_b)`, then the class hierarchies of these types are searched.

  If one KL method is registered between any pairs of classes in these two
  parent hierarchies, it is used.

  If more than one such registered method exists, the method whose registered
  classes have the shortest sum MRO paths to the input types is used.

  If more than one such shortest path exists, the first method
  identified in the search is used (favoring a shorter MRO distance to
  `type(dist_a)`).

  Args:
    dist_a: The first distribution.
    dist_b: The second distribution.
    allow_nan: If `False` (default), a runtime error is raised
      if the KL returns NaN values for any batch entry of the given
      distributions.  If `True`, the KL may return a NaN for the given entry.
    name: (optional) Name scope to use for created operations.

  Returns:
    A Tensor with the batchwise KL-divergence between dist_a and dist_b.

  Raises:
    NotImplementedError: If no KL method is defined for distribution types
      of dist_a and dist_b.
  """
  kl_fn = _registered_kl(type(dist_a), type(dist_b))
  if kl_fn is None:
    raise NotImplementedError(
        "No KL(dist_a || dist_b) registered for dist_a type %s and dist_b "
        "type %s" % ((type(dist_a).__name__, type(dist_b).__name__)))

  with ops.name_scope("KullbackLeibler"):
    kl_t = kl_fn(dist_a, dist_b, name=name)
    if allow_nan:
      return kl_t

    # Check KL for NaNs
    kl_t = array_ops.identity(kl_t, name="kl")

    with ops.control_dependencies([
        control_flow_ops.Assert(
            math_ops.logical_not(
                math_ops.reduce_any(math_ops.is_nan(kl_t))),
            ["KL calculation between %s and %s returned NaN values "
             "(and was called with allow_nan=False).  Values:"
             % (dist_a.name, dist_b.name), kl_t])]):
      return array_ops.identity(kl_t, name="checked_kl")

def _process_scale(self, scale, event_ndims):
    """Helper to __init__ which gets scale in batch-ready form.

    This function expands dimensions of `scale` according to the following
    table:
                     event_ndims
    scale.ndims   0            1
              0  [1]+S+[1,1]   "silent error"
              1  [ ]+S+[1,1]   "silent error"
              2  [ ]+S+[1,1]   [1]+S+[ ]
              3  [ ]+S+[1,1]   [ ]+S+[ ]
            ...  (same)        (same)

    The idea is that we want to convert `scale` into something which can always
    work for, say, the left-hand argument of `batch_matmul`.

    Args:
      scale: `Tensor`.
      event_ndims: `Tensor` (0D, `int32`).

    Returns:
      scale: `Tensor` with dims expanded according to [above] table.
      batch_ndims: `Tensor` (0D, `int32`).  The ndims of the `batch` portion.
    """
    ndims = array_ops.rank(scale)
    left = math_ops.select(
        math_ops.reduce_any([
            math_ops.reduce_all([
                math_ops.equal(ndims, 0),
                math_ops.equal(event_ndims, 0)
            ]),
            math_ops.reduce_all([
                math_ops.equal(ndims, 2),
                math_ops.equal(event_ndims, 1)
            ])]), 1, 0)
    right = math_ops.select(math_ops.equal(event_ndims, 0), 2, 0)
    pad = array_ops.concat(0, (
        array_ops.ones([left], dtype=dtypes.int32),
        array_ops.shape(scale),
        array_ops.ones([right], dtype=dtypes.int32)))
    scale = array_ops.reshape(scale, pad)
    batch_ndims = ndims - 2 + right
    # For safety, explicitly zero-out the upper triangular part.
    scale = array_ops.matrix_band_part(scale, -1, 0)
    if self.validate_args:
      # matrix_band_part will fail if scale is not at least rank 2.
      shape = array_ops.shape(scale)
      assert_square = check_ops.assert_equal(
          shape[-2], shape[-1],
          message="Input must be a (batch of) square matrix.")
      # Assuming lower-triangular means we only need check diag != 0.
      diag = array_ops.matrix_diag_part(scale)
      is_non_singular = math_ops.logical_not(
          math_ops.reduce_any(
              math_ops.equal(diag, ops.convert_to_tensor(0, dtype=diag.dtype))))
      assert_non_singular = control_flow_ops.Assert(
          is_non_singular, ["Singular matrix encountered", diag])
      scale = control_flow_ops.with_dependencies(
          [assert_square, assert_non_singular], scale)
    return scale, batch_ndims

def decode_image(contents, channels=None, name=None):
  """Convenience function for `decode_gif`, `decode_jpeg`, and `decode_png`.
  Detects whether an image is a GIF, JPEG, or PNG, and performs the appropriate
  operation to convert the input bytes `string` into a `Tensor` of type `uint8`.

  Note: `decode_gif` returns a 4-D array `[num_frames, height, width, 3]`, as
  opposed to `decode_jpeg` and `decode_png`, which return 3-D arrays
  `[height, width, num_channels]`. Make sure to take this into account when
  constructing your graph if you are intermixing GIF files with JPEG and/or PNG
  files.

  Args:
    contents: 0-D `string`. The encoded image bytes.
    channels: An optional `int`. Defaults to `0`. Number of color channels for
      the decoded image.
    name: A name for the operation (optional)

  Returns:
    `Tensor` with type `uint8` with shape `[height, width, num_channels]` for
      JPEG and PNG images and shape `[num_frames, height, width, 3]` for GIF
      images.
  """
  with ops.name_scope(name, 'decode_image') as scope:
    if channels not in (None, 0, 1, 3):
      raise ValueError('channels must be in (None, 0, 1, 3)')
    substr = tf.substr(contents, 0, 4)

    def _gif():
      # Create assert op to check that bytes are GIF decodable
      is_gif = tf.equal(substr, b'\x47\x49\x46\x38', name='is_gif')
      decode_msg = 'Unable to decode bytes as JPEG, PNG, or GIF'
      assert_decode = control_flow_ops.Assert(is_gif, [decode_msg])
      # Create assert to make sure that channels is not set to 1
      # Already checked above that channels is in (None, 0, 1, 3)
      gif_channels = 0 if channels is None else channels
      good_channels = tf.not_equal(gif_channels, 1, name='check_channels')
      channels_msg = 'Channels must be in (None, 0, 3) when decoding GIF images'
      assert_channels = control_flow_ops.Assert(good_channels, [channels_msg])
      with ops.control_dependencies([assert_decode, assert_channels]):
        return gen_image_ops.decode_gif(contents)

    def _png():
      return gen_image_ops.decode_png(contents, channels)

    def check_png():
      is_png = tf.equal(substr, b'\211PNG', name='is_png')
      return control_flow_ops.cond(is_png, _png, _gif, name='cond_png')

    def _jpeg():
      return gen_image_ops.decode_jpeg(contents, channels)

    is_jpeg = tf.logical_or(tf.equal(substr, b'\xff\xd8\xff\xe0', name='is_jpeg0'),
                           tf.equal(substr, b'\xff\xd8\xff\xe1', name='is_jpeg0'))

    return control_flow_ops.cond(is_jpeg, _jpeg, check_png, name='cond_jpeg')

def make_dense_examples_and_variables_dicts(dense_features_values, weights,
                                            labels):
  """Creates examples and variables dictionaries for dense features.

  Variables shapes are inferred from the list of dense feature values passed as
  argument.

  Args:
    dense_features_values: The values of the dense features
    weights: The example weights.
    labels: The example labels.
  Returns:
    One dictionary for the examples and one for the variables.
  """
  dense_tensors = []
  dense_weights = []
  for dense_feature in dense_features_values:
    dense_tensor = ops.convert_to_tensor(dense_feature, dtype=dtypes.float32)
    check_shape_op = control_flow_ops.Assert(
        math_ops.less_equal(array_ops.rank(dense_tensor), 2),
        ['dense_tensor shape must be [batch_size, dimension] or [batch_size]'])
    # Reshape to [batch_size, dense_column_dimension].
    with ops.control_dependencies([check_shape_op]):
      dense_tensor = array_ops.reshape(
          dense_tensor, [dense_tensor.get_shape().as_list()[0], -1])
    dense_tensors.append(dense_tensor)
    # Add variables of shape [feature_column_dimension].
    dense_weights.append(
        variables_lib.Variable(
            array_ops.zeros(
                [dense_tensor.get_shape().as_list()[1]], dtype=dtypes.float32)))

  examples_dict = dict(
      sparse_features=[],
      dense_features=dense_tensors,
      example_weights=weights,
      example_labels=labels,
      example_ids=['%d' % i for i in range(0, len(labels))])
  variables_dict = dict(
      sparse_features_weights=[], dense_features_weights=dense_weights)

  return examples_dict, variables_dict

def kl(dist_a, dist_b, allow_nan=False, name=None):
  """Get the KL-divergence KL(dist_a || dist_b).

  If there is no KL method registered specifically for `type(dist_a)` and
  `type(dist_b)`, then the class hierarchies of these types are searched.

  If one KL method is registered between any pairs of classes in these two
  parent hierarchies, it is used.

  If more than one such registered method exists, the method whose registered
  classes have the shortest sum MRO paths to the input types is used.

  If more than one such shortest path exists, the first method
  identified in the search is used (favoring a shorter MRO distance to
  `type(dist_a)`).

  Args:
    dist_a: The first distribution.
    dist_b: The second distribution.
    allow_nan: If `False` (default), a runtime error is raised
      if the KL returns NaN values for any batch entry of the given
      distributions.  If `True`, the KL may return a NaN for the given entry.
    name: (optional) Name scope to use for created operations.

  Returns:
    A Tensor with the batchwise KL-divergence between dist_a and dist_b.

  Raises:
    NotImplementedError: If no KL method is defined for distribution types
      of dist_a and dist_b.
  """
  kl_fn = _registered_kl(type(dist_a), type(dist_b))
  if kl_fn is None:
    raise NotImplementedError(
        "No KL(dist_a || dist_b) registered for dist_a type %s and dist_b "
        "type %s" % ((type(dist_a).__name__, type(dist_b).__name__)))

  with ops.name_scope("KullbackLeibler"):
    kl_t = kl_fn(dist_a, dist_b, name=name)
    if allow_nan:
      return kl_t

    # Check KL for NaNs
    kl_t = array_ops.identity(kl_t, name="kl")

    with ops.control_dependencies([
        control_flow_ops.Assert(
            math_ops.logical_not(
                math_ops.reduce_any(math_ops.is_nan(kl_t))),
            ["KL calculation between %s and %s returned NaN values "
             "(and was called with allow_nan=False).  Values:"
             % (dist_a.name, dist_b.name), kl_t])]):
      return array_ops.identity(kl_t, name="checked_kl")