Python standard_ops.constant函数代码示例

 def testGroup_MultiDevice(self):
     with ops.Graph().as_default() as g:
         with g.device("/task:0"):
             a = tf.constant(0, name="a")
             b = tf.constant(0, name="b")
         with g.device("/task:1"):
             c = tf.constant(0, name="c")
             d = tf.constant(0, name="d")
         with g.device("/task:2"):
             tf.group(a.op, b.op, c.op, d.op, name="root")
     gd = g.as_graph_def()
     self.assertProtoEquals(
         """
   node { name: "a" op: "Const" device: "/task:0"}
   node { name: "b" op: "Const" device: "/task:0"}
   node { name: "c" op: "Const" device: "/task:1"}
   node { name: "d" op: "Const" device: "/task:1"}
   node { name: "root/NoOp" op: "NoOp" input: "^a" input: "^b"
          device: "/task:0" }
   node { name: "root/NoOp_1" op: "NoOp" input: "^c" input: "^d"
          device: "/task:1" }
   node { name: "root" op: "NoOp" input: "^root/NoOp" input: "^root/NoOp_1"
          device: "/task:2" }
 """,
         self._StripGraph(gd),
     )

  def testIndexedSlicesGradientInCondInWhileLoop(self):
    with ops.Graph().as_default():
      embedding_matrix = tf.get_variable(
          "embedding_matrix", [5, 5],
          initializer=tf.random_normal_initializer())

      def Cond(it, _):
        return it < 5
      def Body(it, cost):
        embedding = embedding_ops.embedding_lookup(embedding_matrix, [0])
        cost = tf.cond(tf.equal(it, 3),
                       lambda: tf.square(cost),
                       lambda: cost + tf.reduce_sum(embedding))
        return it + 1, cost
      _, cost = control_flow_ops.While(
          Cond, Body, [tf.constant(0), tf.constant(0.0)])

      dynamic_grads = tf.gradients(cost, [embedding_matrix])[0]
      dynamic_grads = tf.segment_sum(dynamic_grads.values,
                                     dynamic_grads.indices)

      embedding = embedding_ops.embedding_lookup(embedding_matrix, [0])
      static = tf.square(
          tf.reduce_sum(embedding) +
          tf.reduce_sum(embedding) +
          tf.reduce_sum(embedding)) + tf.reduce_sum(embedding)
      static_grads = tf.gradients(static, [embedding_matrix])[0]
      static_grads = tf.segment_sum(static_grads.values, static_grads.indices)

      with self.test_session() as sess:
        sess.run(tf.initialize_all_variables())
        self.assertAllEqual(*sess.run([static_grads, dynamic_grads]))

 def testShape(self):
   with ops.Graph().as_default():
     tensor = tf.constant([1.0, 2.0])
     self.assertEquals([2], tensor.get_shape())
     self.assertEquals([2],
                       control_flow_ops.with_dependencies(
                           [tf.constant(1.0)], tensor).get_shape())

 def testIndexedSlicesWithDenseShape(self):
     with self.test_session():
         data = ops.IndexedSlices(tf.constant([1, 2, 3]), tf.constant([0, 1]), dense_shape=tf.constant([3]))
         zero = tf.constant(0)
         one = tf.constant(1)
         less_op = tf.less(zero, one)
         switch_false, switch_true = control_flow_ops.switch(data, less_op)
         self.assertAllEqual([1, 2, 3], switch_true.values.eval())
         self.assertAllEqual([0, 1], switch_true.indices.eval())

 def testGroup_OneDevice(self):
   with ops.Graph().as_default() as g:
     with g.device("/task:0"):
       a = tf.constant(0, name="a")
       b = tf.constant(0, name="b")
     tf.group(a.op, b.op, name="root")
   gd = g.as_graph_def()
   self.assertProtoEquals("""
     node { name: "a" op: "Const" device: "/task:0" }
     node { name: "b" op: "Const" device: "/task:0" }
     node { name: "root" op: "NoOp" input: "^a" input: "^b" device: "/task:0" }
   """, self._StripGraph(gd))

 def testGroup_NoDevices(self):
   with ops.Graph().as_default() as g:
     a = tf.constant(0, name="a")
     b = tf.constant(0, name="b")
     c = tf.constant(0, name="c")
     tf.group(a.op, b.op, c.op, name="root")
   gd = g.as_graph_def()
   self.assertProtoEquals("""
     node { name: "a" op: "Const"}
     node { name: "b" op: "Const"}
     node { name: "c" op: "Const"}
     node { name: "root" op: "NoOp" input: "^a" input: "^b" input: "^c" }
   """, self._StripGraph(gd))

 def testCondContext(self):
   with self.test_session() as sess:
     x = tf.constant(2)
     y = tf.constant(5)
     control_flow_ops.cond(tf.less(x, y),
                           lambda: tf.mul(x, 17),
                           lambda: tf.add(y, 23))
     for op in sess.graph.get_operations():
       c = op._get_control_flow_context()
       if c:
         compare.ProtoEq(
             c.to_proto(),
             control_flow_ops.CondContext.from_proto(c.to_proto()).to_proto())

  def testIndexedSlicesWithShapeGradientInWhileLoop(self):
    with self.test_session() as sess:
      num_steps = 9

      inputs = tf.placeholder(dtype="float32", shape=[num_steps])
      initial_outputs = tf.TensorArray(dtype="float32", size=num_steps)
      initial_i = tf.constant(0, dtype="int32")

      def Cond(i, _):
        return i < num_steps

      def Body(i, outputs):
        x = tf.gather(inputs, i)
        outputs = outputs.write(i, x)
        return i + 1, outputs

      _, outputs = tf.while_loop(Cond, Body, [initial_i, initial_outputs])

      outputs = tf.reduce_sum(outputs.pack())
      r = tf.gradients([outputs], [inputs])[0]
      grad_wr_inputs = ops.convert_to_tensor(r)
      o, grad = sess.run([outputs, grad_wr_inputs],
                         feed_dict={inputs: [4, 6, 0, 7, 0, 0, 1, 2, 0]})
      self.assertEquals(o, 20)
      self.assertAllEqual(grad, [1] * num_steps)

def _maximal_eigenvector_power_method(matrix,
                                      epsilon=1e-6,
                                      maximum_iterations=100):
  """Returns the maximal right-eigenvector of `matrix` using the power method.

  Args:
    matrix: 2D Tensor, the matrix of which we will find the maximal
      right-eigenvector.
    epsilon: nonnegative float, if two iterations of the power method differ (in
      L2 norm) by no more than epsilon, we will terminate.
    maximum_iterations: nonnegative int, if we perform this many iterations, we
      will terminate.

  Result:
    The maximal right-eigenvector of `matrix`.

  Raises:
    ValueError: If the `matrix` tensor is not floating-point, or if the
      `epsilon` or `maximum_iterations` parameters violate their bounds.
  """
  if not matrix.dtype.is_floating:
    raise ValueError("multipliers must have a floating-point dtype")
  if epsilon <= 0.0:
    raise ValueError("epsilon must be strictly positive")
  if maximum_iterations <= 0:
    raise ValueError("maximum_iterations must be strictly positive")

  def while_loop_condition(iteration, eigenvector, old_eigenvector):
    """Returns false if the while loop should terminate."""
    not_done = (iteration < maximum_iterations)
    not_converged = (standard_ops.norm(eigenvector - old_eigenvector) > epsilon)
    return standard_ops.logical_and(not_done, not_converged)

  def while_loop_body(iteration, eigenvector, old_eigenvector):
    """Performs one iteration of the power method."""
    del old_eigenvector  # Needed by the condition, but not the body.
    iteration += 1
    # We need to use tf.matmul() and tf.expand_dims(), instead of
    # tf.tensordot(), since the former will infer the shape of the result, while
    # the latter will not (tf.while_loop() needs the shapes).
    new_eigenvector = standard_ops.matmul(
        matrix, standard_ops.expand_dims(eigenvector, 1))[:, 0]
    new_eigenvector /= standard_ops.norm(new_eigenvector)
    return (iteration, new_eigenvector, eigenvector)

  iteration = standard_ops.constant(0)
  eigenvector = standard_ops.ones_like(matrix[:, 0])
  eigenvector /= standard_ops.norm(eigenvector)

  # We actually want a do-while loop, so we explicitly call while_loop_body()
  # once before tf.while_loop().
  iteration, eigenvector, old_eigenvector = while_loop_body(
      iteration, eigenvector, eigenvector)
  iteration, eigenvector, old_eigenvector = control_flow_ops.while_loop(
      while_loop_condition,
      while_loop_body,
      loop_vars=(iteration, eigenvector, old_eigenvector),
      name="power_method")

  return eigenvector

  def testIndexedSlicesWithDynamicShapeGradientInWhileLoop(self):
    for dtype in [dtypes.float32, dtypes.float64]:
      with self.test_session() as sess:
        inputs = tf.placeholder(dtype=dtype)
        initial_outputs = tf.TensorArray(dtype=dtype, dynamic_size=True,
                                         size=1)
        initial_i = tf.constant(0, dtype=dtypes.int32)

        def Cond(i, _):
          return i < tf.size(inputs)  # pylint: disable=cell-var-from-loop

        def Body(i, outputs):
          x = tf.gather(inputs, i)  # pylint: disable=cell-var-from-loop
          outputs = outputs.write(i, x)
          return i + 1, outputs

        _, outputs = tf.while_loop(Cond, Body, [initial_i, initial_outputs])

        outputs = tf.reduce_sum(outputs.pack())
        r = tf.gradients([outputs], [inputs])[0]
        grad_wr_inputs = ops.convert_to_tensor(r)
        o, grad = sess.run([outputs, grad_wr_inputs],
                           feed_dict={inputs: [1, 3, 2]})
        self.assertEquals(o, 6)
        self.assertAllEqual(grad, [1] * 3)

 def _initial_state(self, num_constraints):
   # For a MultiplicativeSwapRegretOptimizer, the internal state is a tensor of
   # shape (m+1,m+1), where m is the number of constraints, representing the
   # element-wise logarithm of a left-stochastic matrix.
   dimension = num_constraints + 1
   # Initialize by putting as much weight as possible on the objective, and as
   # little as possible on the constraints.
   log_initial_one = math.log(1.0 - (self._initial_multiplier_radius *
                                     (dimension - 1) / (dimension)))
   log_initial_zero = math.log(self._initial_multiplier_radius / dimension)
   return standard_ops.concat(
       (standard_ops.constant(
           log_initial_one, dtype=dtypes.float32, shape=(1, dimension)),
        standard_ops.constant(
            log_initial_zero,
            dtype=dtypes.float32,
            shape=(dimension - 1, dimension))),
       axis=0)

 def testIndexedSlicesGradient(self):
   with ops.Graph().as_default():
     embedding_matrix = tf.get_variable(
         "embedding_matrix", [5, 5],
         initializer=tf.random_normal_initializer())
     def Cond(it, _):
       return it < 5
     def Body(it, cost):
       embedding = embedding_ops.embedding_lookup(embedding_matrix + 0.0, [0])
       cost += tf.reduce_sum(embedding)
       return it + 1, cost
     _, cost = control_flow_ops.While(
         Cond, Body, [tf.constant(0), tf.constant(0.0)])
     optimizer = momentum.MomentumOptimizer(0.1, 0.9)
     train_op = optimizer.minimize(cost)
     with self.test_session() as sess:
       sess.run(tf.initialize_all_variables())
       for _ in range(10):
         sess.run([train_op])

  def test_maximum_eigenvector_power_method(self):
    """Tests power method routine on some known left-stochastic matrices."""
    matrix1 = np.matrix([[0.6, 0.1, 0.1], [0.0, 0.6, 0.9], [0.4, 0.3, 0.0]])
    matrix2 = np.matrix([[0.4, 0.4, 0.2], [0.2, 0.1, 0.5], [0.4, 0.5, 0.3]])

    with self.test_session() as session:
      eigenvector1 = session.run(
          swap_regret_optimizer._maximal_eigenvector_power_method(
              standard_ops.constant(matrix1)))
      eigenvector2 = session.run(
          swap_regret_optimizer._maximal_eigenvector_power_method(
              standard_ops.constant(matrix2)))

    # Check that eigenvector1 and eigenvector2 are eigenvectors of matrix1 and
    # matrix2 (respectively) with associated eigenvalue 1.
    matrix_eigenvector1 = np.tensordot(matrix1, eigenvector1, axes=1)
    matrix_eigenvector2 = np.tensordot(matrix2, eigenvector2, axes=1)
    self.assertAllClose(eigenvector1, matrix_eigenvector1, rtol=0, atol=1e-6)
    self.assertAllClose(eigenvector2, matrix_eigenvector2, rtol=0, atol=1e-6)

 def testWhileContext(self):
   with self.test_session() as sess:
     i = tf.constant(0)
     c = lambda i: tf.less(i, 10)
     b = lambda i: tf.add(i, 1)
     tf.while_loop(c, b, [i])
     for op in sess.graph.get_operations():
       c = op._get_control_flow_context()
       if c:
         compare.ProtoEq(
             c.to_proto(),
             control_flow_ops.WhileContext.from_proto(c.to_proto()).to_proto())

  def __init__(self, constraints):
    """Constructs a new `ConstantMinimizationProblem'.

    Args:
      constraints: 1d numpy array, the constant constraint violations.

    Returns:
      A new `ConstantMinimizationProblem'.
    """
    # We make an fake 1-parameter linear objective so that we don't get a "no
    # variables to optimize" error.
    self._objective = standard_ops.Variable(0.0, dtype=dtypes.float32)
    self._constraints = standard_ops.constant(constraints, dtype=dtypes.float32)