Python functional_ops.map_fn函数代码示例

  def testMap_Scoped(self):
    with self.cached_session() as sess:

      def double_scoped(x):
        """2x with a dummy 2 that is scoped."""
        with variable_scope.variable_scope("body"):
          # Dummy variable, just to check that scoping works as intended.
          two = variable_scope.get_variable(
              "two", [],
              dtype=dtypes.int32,
              initializer=init_ops.constant_initializer(2))
          return math_ops.multiply(x, two)

      with variable_scope.variable_scope("root") as varscope:
        elems = constant_op.constant([1, 2, 3, 4, 5, 6], name="data")
        doubles = np.array([2 * x for x in [1, 2, 3, 4, 5, 6]])

        r = functional_ops.map_fn(double_scoped, elems)
        # Check that we have the one variable we asked for here.
        self.assertEqual(len(variables.trainable_variables()), 1)
        self.assertEqual(variables.trainable_variables()[0].name,
                         "root/body/two:0")
        sess.run([variables.global_variables_initializer()])
        self.assertAllEqual(doubles, self.evaluate(r))

        # Now let's reuse our single variable.
        varscope.reuse_variables()
        r = functional_ops.map_fn(double_scoped, elems)
        self.assertEqual(len(variables.trainable_variables()), 1)
        self.assertAllEqual(doubles, self.evaluate(r))

 def testMapSparseTensor(self):
   with self.cached_session():
     with self.assertRaises(TypeError):
       functional_ops.map_fn(
           lambda x: x,
           sparse_tensor.SparseTensor(
               indices=[[0, 0], [0, 1], [1, 0]],
               values=constant_op.constant([0, 1, 2]),
               dense_shape=[2, 2]))

 def testMap_MultiOutputMismatchedDtype(self):
   nums = np.array([1, 2, 3, 4, 5, 6])
   with self.assertRaisesRegexp(
       TypeError, r"two structures don't have the same nested structure"):
     # lambda emits tuple, but dtype is a list
     functional_ops.map_fn(
         lambda x: ((x + 3) * 2, -(x + 3) * 2),
         nums,
         dtype=[dtypes.int64, dtypes.int64])

 def testMap_Simple(self):
   nums = [1, 2, 3, 4, 5, 6]
   elems = constant_op.constant(nums, name="data")
   r = functional_ops.map_fn(
       lambda x: math_ops.multiply(math_ops.add(x, 3), 2), elems)
   self.assertAllEqual(
       np.array([(x + 3) * 2 for x in nums]), self.evaluate(r))

  def _sample_n(self, n, seed=None):
    n_draws = math_ops.cast(self.total_count, dtype=dtypes.int32)
    k = self.event_shape_tensor()[0]

    # broadcast the total_count and logits to same shape
    n_draws = array_ops.ones_like(
        self.logits[..., 0], dtype=n_draws.dtype) * n_draws
    logits = array_ops.ones_like(
        n_draws[..., array_ops.newaxis], dtype=self.logits.dtype) * self.logits

    # flatten the total_count and logits
    flat_logits = array_ops.reshape(logits, [-1, k])  # [B1B2...Bm, k]
    flat_ndraws = n * array_ops.reshape(n_draws, [-1])  # [B1B2...Bm]

    # computes each total_count and logits situation by map_fn
    def _sample_single(args):
      logits, n_draw = args[0], args[1]  # [K], []
      x = random_ops.multinomial(logits[array_ops.newaxis, ...], n_draw,
                                 seed)  # [1, n*n_draw]
      x = array_ops.reshape(x, shape=[n, -1])  # [n, n_draw]
      x = math_ops.reduce_sum(array_ops.one_hot(x, depth=k), axis=-2)  # [n, k]
      return x

    x = functional_ops.map_fn(
        _sample_single, [flat_logits, flat_ndraws],
        dtype=self.dtype)  # [B1B2...Bm, n, k]

    # reshape the results to proper shape
    x = array_ops.transpose(x, perm=[1, 0, 2])
    final_shape = array_ops.concat([[n], self.batch_shape_tensor(), [k]], 0)
    x = array_ops.reshape(x, final_shape)  # [n, B1, B2,..., Bm, k]
    return x

 def testMap_SimpleNotTensor(self):
   with self.test_session():
     nums = np.array([1, 2, 3, 4, 5, 6])
     r = functional_ops.map_fn(
         lambda x: math_ops.multiply(math_ops.add(x, 3), 2), nums)
     self.assertAllEqual(
         np.array([(x + 3) * 2 for x in nums]), self.evaluate(r))

 def compute_activations(elems):
   return functional_ops.map_fn(fn=classifier_fn,
                                elems=elems,
                                parallel_iterations=1,
                                back_prop=False,
                                swap_memory=True,
                                name='RunClassifier')

def sparse_boolean_mask(sparse_tensor, mask, name="sparse_boolean_mask"):
  """Boolean mask for `SparseTensor`s.

  Args:
    sparse_tensor: a `SparseTensor`.
    mask: a 1D boolean dense`Tensor` whose length is equal to the 0th dimension
      of `sparse_tensor`.
    name: optional name for this operation.
  Returns:
    A `SparseTensor` that contains row `k` of `sparse_tensor` iff `mask[k]` is
    `True`.
  """
  # TODO(jamieas): consider mask dimension > 1 for symmetry with `boolean_mask`.
  with ops.op_scope([sparse_tensor, mask], name):
    mask = ops.convert_to_tensor(mask)
    mask_rows = array_ops.where(mask)
    first_indices = array_ops.squeeze(array_ops.slice(sparse_tensor.indices,
                                                      [0, 0], [-1, 1]))

    # Identify indices corresponding to the rows identified by mask_rows.
    sparse_entry_matches = functional_ops.map_fn(
        lambda x: math_ops.equal(first_indices, x),
        mask_rows,
        dtype=dtypes.bool)
    # Combine the rows of index_matches to form a mask for the sparse indices
    # and values.
    to_retain = array_ops.reshape(
        functional_ops.foldl(math_ops.logical_or, sparse_entry_matches), [-1])

    return sparse_ops.sparse_retain(sparse_tensor, to_retain)

def ctc_unique_labels(labels, name=None):
  """Get unique labels and indices for batched labels for tf.nn.ctc_loss.

  For use with tf.nn.ctc_loss_v2 optional argument `unique`: This op can be
  used to preprocess labels in input pipeline to for better speed/memory use
  computing the ctc loss on TPU.

  Example:
    ctc_unique_labels([[3, 4, 4, 3]]) ->
      unique labels padded with 0: [[3, 4, 0, 0]]
      indices of original labels in unique: [0, 1, 1, 0]

  Args:
    labels: tensor of shape [batch_size, max_label_length] padded with 0.
    name: A name for this `Op`. Defaults to "ctc_unique_labels".

  Returns:
    tuple of
      - unique labels, tensor of shape `[batch_size, max_label_length]`
      - indices into unique labels, shape `[batch_size, max_label_length]`
  """

  with ops.name_scope(name, "ctc_unique_labels", [labels]):
    labels = ops.convert_to_tensor(labels, name="labels")
    def _unique(x):
      u = array_ops.unique(x)
      y = array_ops.pad(
          u.y, [[0, _get_dim(u.idx, 0) - _get_dim(u.y, 0)]])
      y = math_ops.cast(y, dtypes.int64)
      return [y, u.idx]
    return functional_ops.map_fn(
        _unique, labels, dtype=[dtypes.int64, dtypes.int32])

  def compress(self, inputs):
    """Compress inputs and store their binary representations into strings.

    Args:
      inputs: `Tensor` with values to be compressed.

    Returns:
      String `Tensor` vector containing the compressed representation of each
      batch element of `inputs`.
    """
    with ops.name_scope(self._name_scope()):
      inputs = ops.convert_to_tensor(inputs)
      if not self.built:
        # Check input assumptions set before layer building, e.g. input rank.
        self._assert_input_compatibility(inputs)
        if self.dtype is None:
          self._dtype = inputs.dtype.base_dtype.name
        self.build(inputs.shape)

      # Check input assumptions set after layer building, e.g. input shape.
      if not context.executing_eagerly():
        self._assert_input_compatibility(inputs)

      ndim = self.input_spec.ndim
      channel_axis = self._channel_axis(ndim)
      # Tuple of slices for expanding dimensions of tensors below.
      slices = ndim * [None] + [slice(None)]
      slices[channel_axis] = slice(None)
      slices = tuple(slices)

      # Expand dimensions of CDF to input dimensions, keeping the channels along
      # the right dimension.
      cdf = self._quantized_cdf[slices[1:]]
      num_levels = array_ops.shape(cdf)[-1] - 1

      # Bring inputs to the right range by centering the range on the medians.
      half = constant_op.constant(.5, dtype=self.dtype)
      medians = array_ops.squeeze(self._medians, [1, 2])
      offsets = (math_ops.cast(num_levels // 2, self.dtype) + half) - medians
      # Expand offsets to input dimensions and add to inputs.
      values = inputs + offsets[slices[:-1]]

      # Clip to range and cast to integers. Because we have added .5 above, and
      # all values are positive, the cast effectively implements rounding.
      values = math_ops.maximum(values, half)
      values = math_ops.minimum(
          values, math_ops.cast(num_levels, self.dtype) - half)
      values = math_ops.cast(values, dtypes.int16)

      def loop_body(tensor):
        return coder_ops.range_encode(
            tensor, cdf, precision=self.range_coder_precision)
      strings = functional_ops.map_fn(
          loop_body, values, dtype=dtypes.string, back_prop=False)

      if not context.executing_eagerly():
        strings.set_shape(inputs.shape[:1])

      return strings

 def testMap_MultiInputSingleOutput(self):
   nums = np.array([1, 2, 3, 4, 5, 6])
   r = functional_ops.map_fn(
       lambda x: x[0] * x[1][0] + x[1][1], (nums, (nums, -nums)),
       dtype=dtypes.int64)
   self.assertEqual((6,), r.get_shape())
   received = self.evaluate(r)
   self.assertAllEqual(nums * nums + (-nums), received)

 def testWhileAndTensorArray(self):
   with self.cached_session() as sess:
     param = constant_op.constant(2.0)
     y0 = constant_op.constant([1.0, 2.0, 3.0, 4.0, 5.0, 6.0], name="elems")
     # map_fn uses TensorArray internally.
     r = functional_ops.map_fn(lambda x: math_ops.multiply(x, param), y0)
     self.assertAllClose([2.0, 4.0, 6.0, 8.0, 10.0, 12.0], self.evaluate(r))
     r = gradients_impl.gradients(r, param)[0]
     self.assertAllClose(21.0, self.evaluate(r))

 def build_dataset(row, num):
   # pylint: disable=g-long-lambda
   iterator = dataset_ops.make_initializable_iterator(
       dataset_ops.Dataset.from_tensors(row).map(
           lambda elems: functional_ops.map_fn(
               lambda x: control_map_fn(x, num), elems)))
   init_op = iterator.initializer
   get_next = iterator.get_next()
   return init_op, get_next

def loop():
  random_seed.set_random_seed(0)
  x1 = random_ops.truncated_normal([1, 784], seed=0)
  x2 = random_ops.truncated_normal([1, 784], seed=0)
  x3 = random_ops.truncated_normal([1, 784], seed=0)
  x4 = random_ops.truncated_normal([1, 784], seed=0)
  elems = (x1, x2, x3, x4)
  outputs = functional_ops.map_fn(two_layer_model, elems, dtype=dtypes.float32)
  return outputs

def _loop_with_vec_and_4d():
  random_seed.set_random_seed(0)
  x1 = random_ops.truncated_normal([1, 784], seed=0)
  x2 = random_ops.truncated_normal([1, 784], seed=0)
  x3 = random_ops.truncated_normal([1, 784], seed=0)
  x4 = random_ops.truncated_normal([1, 784], seed=0)
  elems = (x1, x2, x3, x4)
  outputs = functional_ops.map_fn(
      _model_with_vec_and_4d, elems, dtype=dtypes.float32)
  return outputs