Python math_ops.floor函数代码示例

    def compute_step(x_val, geometric=False):
      if geometric:
        # Consider geometric series where t_mul != 1
        # 1 + t_mul + t_mul^2 ... = (1 - t_mul^i_restart) / (1 - t_mul)

        # First find how many restarts were performed for a given x_val
        # Find maximal integer i_restart value for which this equation holds
        # x_val >= (1 - t_mul^i_restart) / (1 - t_mul)
        # x_val * (1 - t_mul) <= (1 - t_mul^i_restart)
        # t_mul^i_restart <= (1 - x_val * (1 - t_mul))

        # tensorflow allows only log with base e
        # i_restart <= log(1 - x_val * (1 - t_mul) / log(t_mul)
        # Find how many restarts were performed

        i_restart = math_ops.floor(
            math_ops.log(c_one - x_val * (c_one - t_mul)) / math_ops.log(t_mul))
        # Compute the sum of all restarts before the current one
        sum_r = (c_one - t_mul ** i_restart) / (c_one - t_mul)
        # Compute our position within the current restart
        x_val = (x_val - sum_r) / t_mul ** i_restart

      else:
        # Find how many restarts were performed
        i_restart = math_ops.floor(x_val)
        # Compute our position within the current restart
        x_val = x_val - i_restart
      return i_restart, x_val

    def compute_step(completed_fraction, geometric=False):
      if geometric:
        i_restart = math_ops.floor(math_ops.log(1.0 - completed_fraction * (
            1.0 - t_mul)) / math_ops.log(t_mul))

        sum_r = (1.0 - t_mul ** i_restart) / (1.0 - t_mul)
        completed_fraction = (completed_fraction - sum_r) / t_mul ** i_restart

      else:
        i_restart = math_ops.floor(completed_fraction)
        completed_fraction = completed_fraction - i_restart

      return i_restart, completed_fraction

      def compute_step(completed_fraction, geometric=False):
        """Helper for `cond` operation."""
        if geometric:
          i_restart = math_ops.floor(
              math_ops.log(1.0 - completed_fraction * (1.0 - t_mul)) /
              math_ops.log(t_mul))

          sum_r = (1.0 - t_mul**i_restart) / (1.0 - t_mul)
          completed_fraction = (completed_fraction - sum_r) / t_mul**i_restart

        else:
          i_restart = math_ops.floor(completed_fraction)
          completed_fraction -= i_restart

        return i_restart, completed_fraction

    def dropout_selu_impl(x, rate, alpha, noise_shape, seed, name):
        keep_prob = 1.0 - rate
        x = ops.convert_to_tensor(x, name="x")
        if isinstance(keep_prob, numbers.Real) and not 0. < keep_prob <= 1.:
            raise ValueError("keep_prob must be a scalar tensor or a float in the "
                                             "range (0, 1], got %g" % keep_prob)
        keep_prob = ops.convert_to_tensor(keep_prob, dtype=x.dtype, name="keep_prob")
        keep_prob.get_shape().assert_is_compatible_with(tensor_shape.scalar())

        alpha = ops.convert_to_tensor(alpha, dtype=x.dtype, name="alpha")
        keep_prob.get_shape().assert_is_compatible_with(tensor_shape.scalar())

        if tensor_util.constant_value(keep_prob) == 1:
            return x

        noise_shape = noise_shape if noise_shape is not None else array_ops.shape(x)
        random_tensor = keep_prob
        random_tensor += random_ops.random_uniform(noise_shape, seed=seed, dtype=x.dtype)
        binary_tensor = math_ops.floor(random_tensor)
        ret = x * binary_tensor + alpha * (1-binary_tensor)

        a = tf.sqrt(fixedPointVar / (keep_prob *((1-keep_prob) * tf.pow(alpha-fixedPointMean,2) + fixedPointVar)))

        b = fixedPointMean - a * (keep_prob * fixedPointMean + (1 - keep_prob) * alpha)
        ret = a * ret + b
        ret.set_shape(x.get_shape())
        return ret

 def _log_unnormalized_prob(self, x):
   if self.validate_args:
     x = distribution_util.embed_check_nonnegative_integer_form(x)
   else:
     # For consistency with cdf, we take the floor.
     x = math_ops.floor(x)
   return x * self.log_rate - math_ops.lgamma(1. + x)

  def _log_cdf(self, y):
    low = self._low
    high = self._high

    # Recall the promise:
    # cdf(y) := P[Y <= y]
    #         = 1, if y >= high,
    #         = 0, if y < low,
    #         = P[X <= y], otherwise.

    # P[Y <= j] = P[floor(Y) <= j] since mass is only at integers, not in
    # between.
    j = math_ops.floor(y)

    result_so_far = self.distribution.log_cdf(j)

    # Broadcast, because it's possible that this is a single distribution being
    # evaluated on a number of samples, or something like that.
    j += array_ops.zeros_like(result_so_far)

    # Re-define values at the cutoffs.
    if low is not None:
      neg_inf = -np.inf * array_ops.ones_like(result_so_far)
      result_so_far = array_ops.where(j < low, neg_inf, result_so_far)
    if high is not None:
      result_so_far = array_ops.where(j >= high,
                                      array_ops.zeros_like(result_so_far),
                                      result_so_far)

    return result_so_far

def exponential_decay(learning_rate, global_step, decay_steps, decay_rate,
                      staircase=False, name=None):
  """Applies exponential decay to the learning rate.

  When training a model, it is often recommended to lower the learning rate as
  the training progresses.  This function applies an exponential decay function
  to a provided initial learning rate.  It requires a `global_step` value to
  compute the decayed learning rate.  You can just pass a TensorFlow variable
  that you increment at each training step.

  The function returns the decayed learning rate.  It is computed as:

  ```python
  decayed_learning_rate = learning_rate *
                          decay_rate ^ (global_step / decay_steps)
  ```

  If the argument `staircase` is `True`, then `global_step /decay_steps` is an
  integer division and the decayed learning rate follows a staircase function.

  Example: decay every 100000 steps with a base of 0.96:

  ```python
  ...
  global_step = tf.Variable(0, trainable=False)
  starter_learning_rate = 0.1
  learning_rate = tf.exponential_decay(starter_learning_rate, global_step,
                                       100000, 0.96, staircase=True)
  optimizer = tf.GradientDescent(learning_rate)
  # Passing global_step to minimize() will increment it at each step.
  optimizer.minimize(...my loss..., global_step=global_step)
  ```

  Args:
    learning_rate: A scalar `float32` or `float64` `Tensor` or a
      Python number.  The initial learning rate.
    global_step: A scalar `int32` or `int64` `Tensor` or a Python number.
      Global step to use for the decay computation.  Must not be negative.
    decay_steps: A scalar `int32` or `int64` `Tensor` or a Python number.
      Must be positive.  See the decay computation above.
    decay_rate: A scalar `float32` or `float64` `Tensor` or a
      Python number.  The decay rate.
    staircase: Boolean.  It `True` decay the learning rate at discrete intervals.
    name: string.  Optional name of the operation.  Defaults to 'ExponentialDecay'

  Returns:
    A scalar `Tensor` of the same type as `learning_rate`.  The decayed
    learning rate.
  """
  with ops.op_scope([learning_rate, global_step, decay_steps, decay_rate],
                   name, "ExponentialDecay") as name:
    learning_rate = ops.convert_to_tensor(learning_rate, name="learning_rate")
    dtype = learning_rate.dtype
    global_step = math_ops.cast(global_step, dtype)
    decay_steps = math_ops.cast(decay_steps, dtype)
    decay_rate = math_ops.cast(decay_rate, dtype)
    p = global_step / decay_steps
    if staircase:
      p = math_ops.floor(p)
    return math_ops.mul(learning_rate, math_ops.pow(decay_rate, p), name=name)

 def _cdf(self, x):
   if self.validate_args:
     # We set `check_integer=False` since the CDF is defined on whole real
     # line.
     x = distribution_util.embed_check_nonnegative_discrete(
         x, check_integer=False)
   return math_ops.igammac(math_ops.floor(x + 1), self.rate)

 def testChi2WithAbsDf(self):
   with self.cached_session():
     df_v = np.array([-1.3, -3.2, 5], dtype=np.float64)
     chi2 = chi2_lib.Chi2WithAbsDf(df=df_v)
     self.assertAllClose(
         math_ops.floor(math_ops.abs(df_v)).eval(),
         chi2.df.eval())

  def _cdf(self, y):
    lower_cutoff = self._lower_cutoff
    upper_cutoff = self._upper_cutoff

    # Recall the promise:
    # cdf(y) := P[Y <= y]
    #         = 1, if y >= upper_cutoff,
    #         = 0, if y < lower_cutoff,
    #         = P[X <= y], otherwise.

    # P[Y <= j] = P[floor(Y) <= j] since mass is only at integers, not in
    # between.
    j = math_ops.floor(y)

    # P[X <= j], used when lower_cutoff < X < upper_cutoff.
    result_so_far = self.distribution.cdf(j)

    # Broadcast, because it's possible that this is a single distribution being
    # evaluated on a number of samples, or something like that.
    j += array_ops.zeros_like(result_so_far)

    # Re-define values at the cutoffs.
    if lower_cutoff is not None:
      result_so_far = math_ops.select(j < lower_cutoff,
                                      array_ops.zeros_like(result_so_far),
                                      result_so_far)
    if upper_cutoff is not None:
      result_so_far = math_ops.select(j >= upper_cutoff,
                                      array_ops.ones_like(result_so_far),
                                      result_so_far)

    return result_so_far

def inverse_time_decay(learning_rate, global_step, decay_steps, decay_rate,
                       staircase=False, name=None):
  """Applies inverse time decay to the initial learning rate.

  When training a model, it is often recommended to lower the learning rate as
  the training progresses.  This function applies an inverse decay function
  to a provided initial learning rate.  It requires an `global_step` value to
  compute the decayed learning rate.  You can just pass a TensorFlow variable
  that you increment at each training step.

  The function returns the decayed learning rate.  It is computed as:

  ```python
  decayed_learning_rate = learning_rate / (1 + decay_rate * t)
  ```

  Example: decay 1/t with a rate of 0.5:

  ```python
  ...
  global_step = tf.Variable(0, trainable=False)
  learning_rate = 0.1
  k = 0.5
  learning_rate = tf.train.inverse_time_decay(learning_rate, global_step, k)

  # Passing global_step to minimize() will increment it at each step.
  learning_step = (
      tf.train.GradientDescentOptimizer(learning_rate)
      .minimize(...my loss..., global_step=global_step)
  )
  ```

  Args:
    learning_rate: A scalar `float32` or `float64` `Tensor` or a
      Python number.  The initial learning rate.
    global_step: A Python number.
      Global step to use for the decay computation.  Must not be negative.
    decay_rate: A Python number.  The decay rate.
    name: String.  Optional name of the operation.  Defaults to
      'InverseTimeDecay'

  Returns:
    A scalar `Tensor` of the same type as `learning_rate`.  The decayed
    learning rate.
  """

  with ops.name_scope(name, "InverseTimeDecay",
                      [learning_rate, global_step, decay_rate]) as name:
    learning_rate = ops.convert_to_tensor(learning_rate, name="learning_rate")
    dtype = learning_rate.dtype
    global_step = math_ops.cast(global_step, dtype)
    decay_steps = math_ops.cast(decay_steps, dtype)
    decay_rate = math_ops.cast(decay_rate, dtype)
    p = global_step / decay_steps
    if staircase:
      p = math_ops.floor(p)
    const = math_ops.cast(constant_op.constant(1), learning_rate.dtype)
    denom = math_ops.add(const, math_ops.mul(decay_rate, p))
    return math_ops.div(learning_rate, denom, name=name)

 def dropout(self, input_, keep_prob):
     with ops.op_scope([input_], None, "dropout") as name:
         rands = keep_prob + random_ops.random_uniform(
             array_ops.shape(input_))
         floored = math_ops.floor(rands)
         ret = input_ * math_ops.inv(keep_prob) * floored
         ret.set_shape(input_.get_shape())
         return ret

 def _cdf(self, positive_counts):
   if self.validate_args:
     positive_counts = math_ops.floor(
         distribution_util.embed_check_nonnegative_discrete(
             positive_counts, check_integer=False))
   return math_ops.betainc(
       self.total_count, positive_counts + 1.,
       math_ops.sigmoid(-self.logits))

 def decayed_lr():
   """Helper to recompute learning rate; most helpful in eager-mode."""
   global_step_recomp = math_ops.cast(global_step, dtype)
   p = global_step_recomp / decay_steps
   if staircase:
     p = math_ops.floor(p)
   return math_ops.multiply(
       learning_rate, math_ops.pow(decay_rate, p), name=name)

 def __init__(self, df, validate_args=False, allow_nan_stats=True,
              name="Chi2WithAbsDf"):
   with ops.name_scope(name, values=[df]) as ns:
     super(Chi2WithAbsDf, self).__init__(
         df=math_ops.floor(math_ops.abs(df)),
         validate_args=validate_args,
         allow_nan_stats=allow_nan_stats,
         name=ns)