Python tensorflow.square函数代码示例

    def loss(self):
        # 1. The margin loss

        # [batch_size, 10, 1, 1]
        # max_l = max(0, m_plus-||v_c||)^2
        max_l = tf.square(tf.maximum(0., cfg.m_plus - self.v_length))
        # max_r = max(0, ||v_c||-m_minus)^2
        max_r = tf.square(tf.maximum(0., self.v_length - cfg.m_minus))
        assert max_l.get_shape() == [cfg.batch_size, 10, 1, 1]

        # reshape: [batch_size, 10, 1, 1] => [batch_size, 10]
        max_l = tf.reshape(max_l, shape=(cfg.batch_size, -1))
        max_r = tf.reshape(max_r, shape=(cfg.batch_size, -1))

        # calc T_c: [batch_size, 10]
        # T_c = Y, is my understanding correct? Try it.
        T_c = self.Y
        # [batch_size, 10], element-wise multiply
        L_c = T_c * max_l + cfg.lambda_val * (1 - T_c) * max_r

        self.margin_loss = tf.reduce_mean(tf.reduce_sum(L_c, axis=1))

        # 2. The reconstruction loss
        orgin = tf.reshape(self.X, shape=(cfg.batch_size, -1))
        squared = tf.square(self.decoded - orgin)
        self.reconstruction_err = tf.reduce_mean(squared)

        # 3. Total loss
        # The paper uses sum of squared error as reconstruction error, but we
        # have used reduce_mean in `# 2 The reconstruction loss` to calculate
        # mean squared error. In order to keep in line with the paper,the
        # regularization scale should be 0.0005*784=0.392
        self.total_loss = self.margin_loss + cfg.regularization_scale * self.reconstruction_err

def multilinear_square_product(emb, tuples, l2=0):
    """
     Compute the square-product of real vectors at selected embeddings.
     This is the sum over all dimensions of the square of summed embedding vectors.
    :param emb: embedding matrix of size [n_emb, rank] containing float numbers
    :param tuples: tuple matrix of size [n_t, arity] containing integers
    :param l2: optional l2 regularization strength that is added to the score. If it is different from 0, the function
    returns a pair (pred, l2norm) where pred is the sample prediction, but l2norm is the l2 norm of the selected
    embeddings
    :return: the multilinear square product between selected embeddings
    S[i] = sum_k ( sum_j  E[I[i,k],j] )^2

    >>> emb = [[12., 0, 0], [0, 1, 0], [-1, 1, 1]]
    >>> idx = tf.Variable([[1,0,0],[1,1,0]])
    >>> g = multilinear_square_product(emb, idx)
    >>> print(tf_eval(g))
    [ 577.  148.]
    """
    emb_sel = tf.gather(emb, tuples)
    pred = tf.reduce_sum(tf.square(tf.reduce_sum(emb_sel, 1)), 1)

    if l2 == 0:  # unregularized prediction ==> returns only the predictions
        return pred
    else:  # l2 regularization of the selected embeddings
        reg = l2 * tf.reduce_sum(tf.square(emb_sel))
        return pred, reg

def standard_reg():
    reg = tf.constant(0.0, dtype=tf.float32)
    reg = reg + standard_w_weight_reg * tf.reduce_mean(tf.square(net_params['sDW1']))
    #reg = reg + standard_w_weight_reg * tf.reduce_mean(tf.square(net_params['sDW2']))    
    reg = reg + regressor_w_weight_reg * tf.reduce_mean(tf.square(net_params['sRW']))

    return reg

def triplet_loss(y_true, y_pred, alpha = 0.2):
    """
    Implementation of the triplet loss as defined by formula

    Arguments:
    y_true -- true labels, required when you define a loss in Keras, you don't need it in this function.
    y_pred -- python list containing three objects:
            anchor -- the encodings for the anchor images, of shape (None, 128)
            positive -- the encodings for the positive images, of shape (None, 128)
            negative -- the encodings for the negative images, of shape (None, 128)

    Returns:
    loss -- real number, value of the loss
    """

    anchor, positive, negative = y_pred[0], y_pred[1], y_pred[2]

    ### START CODE HERE ### (≈ 4 lines)
    # Step 1: Compute the (encoding) distance between the anchor and the positive, you will need to sum over axis=-1
    pos_dist = tf.reduce_sum(tf.square(tf.subtract(anchor, positive)))
    # Step 2: Compute the (encoding) distance between the anchor and the negative, you will need to sum over axis=-1
    neg_dist = tf.reduce_sum(tf.square(tf.subtract(anchor, negative)))
    # Step 3: subtract the two previous distances and add alpha.
    basic_loss = tf.add(tf.subtract(pos_dist,neg_dist), alpha)
    # Step 4: Take the maximum of basic_loss and 0.0. Sum over the training examples.
    loss = tf.reduce_sum(tf.maximum(basic_loss, 0.))
    ### END CODE HERE ###

    return loss

    def e_step(o_mean, o_stdv, o_activations, votes):
      """The E-Step in EM Routing.

      :param o_mean: (24, 6, 6, 1, 32, 16)
      :param o_stdv: (24, 6, 6, 1, 32, 16)
      :param o_activations: (24, 6, 6, 1, 32, 1)
      :param votes: (24, 6, 6, 288, 32, 16)

      :return: rr
      """

      o_p_unit0 = - tf.reduce_sum(
        tf.square(votes - o_mean) / (2 * tf.square(o_stdv)), axis=-1, keep_dims=True
      )

      o_p_unit2 = - tf.reduce_sum(
        tf.log(o_stdv + epsilon), axis=-1, keep_dims=True
      )

      # o_p is the probability density of the h-th component of the vote from i to j
      # (24, 6, 6, 1, 32, 16)
      o_p = o_p_unit0 + o_p_unit2

      # rr: (24, 6, 6, 288, 32, 1)
      zz = tf.log(o_activations + epsilon) + o_p
      rr = tf.nn.softmax(
        zz, dim=len(zz.get_shape().as_list())-2
      )

      return rr

        def _ssim_helper(var_x, var_y, max_val, kernel, compensation=1.0):
            """
            Helper function for computing SSIM.
            SSIM estimates covariances with weighted sums.  The default parameters
            use a biased estimate of the covariance:
            Suppose `reducer` is a weighted sum, then the mean estimators are
            mu_x = sum_i w_i x_i,
            mu_y = sum_i w_i y_i,
            where w_i's are the weighted-sum weights, and covariance estimator is
            cov_{xy} = sum_i w_i (x_i - mu_x) (y_i - mu_y)
            with assumption sum_i w_i = 1. This covariance estimator is biased, since
            E[cov_{xy}] = (1 - sum_i w_i ^ 2) Cov(X, Y).
            For SSIM measure with unbiased covariance estimators, pass as `compensation`
            argument (1 - sum_i w_i ^ 2).
            Arguments:
            x: First set of images.
            y: Second set of images.
            reducer: Function that computes 'local' averages from set of images.
              For non-covolutional version, this is usually tf.reduce_mean(x, [1, 2]),
              and for convolutional version, this is usually tf.nn.avg_pool or
              tf.nn.conv2d with weighted-sum kernel.
            max_val: The dynamic range (i.e., the difference between the maximum
              possible allowed value and the minimum allowed value).
            compensation: Compensation factor. See above.
            Returns:
            A pair containing the luminance measure, and the contrast-structure measure.
            """

            def reducer(var_x, kernel):
                shape = tf.shape(var_x)
                var_x = tf.reshape(var_x, shape=tf.concat([[-1], shape[-3:]], 0))
                var_y = tf.nn.depthwise_conv2d(var_x, kernel, strides=[1, 1, 1, 1], padding='VALID')
                return tf.reshape(var_y, tf.concat([shape[:-3], tf.shape(var_y)[1:]], 0))

            _ssim_k1 = 0.01
            _ssim_k2 = 0.03

            c_1 = (_ssim_k1 * max_val) ** 2
            c_2 = (_ssim_k2 * max_val) ** 2

            # SSIM luminance measure is
            # (2 * mu_x * mu_y + c_1) / (mu_x ** 2 + mu_y ** 2 + c_1).
            mean0 = reducer(var_x, kernel)
            mean1 = reducer(var_y, kernel)
            num0 = mean0 * mean1 * 2.0
            den0 = tf.square(mean0) + tf.square(mean1)
            luminance = (num0 + c_1) / (den0 + c_1)

            # SSIM contrast-structure measure is
            #   (2 * cov_{xy} + c_2) / (cov_{xx} + cov_{yy} + c_2).
            # Note that `reducer` is a weighted sum with weight w_k, \sum_i w_i = 1, then
            #   cov_{xy} = \sum_i w_i (x_i - \mu_x) (y_i - \mu_y)
            #          = \sum_i w_i x_i y_i - (\sum_i w_i x_i) (\sum_j w_j y_j).
            num1 = reducer(var_x * var_y, kernel) * 2.0
            den1 = reducer(tf.square(var_x) + tf.square(var_y), kernel)
            c_2 *= compensation
            c_s = (num1 - num0 + c_2) / (den1 - den0 + c_2)

            # SSIM score is the product of the luminance and contrast-structure measures.
            return luminance, c_s

def build_psi_stats_rbf_plus_linear(Z, kern, mu, S):
    # TODO: make sure the acvite dimensions are overlapping completely

    # use only active dimensions
    mu, S = kern._slice(mu, S)  # only use the active dimensions.
    Z, _ = kern._slice(Z, None)

    psi0_lin, psi1_lin, psi2_lin = build_psi_stats_linear(Z, kern.linear, mu, S)
    psi0_rbf, psi1_rbf, psi2_rbf = build_psi_stats_rbf(Z, kern.rbf, mu, S)
    psi0, psi1, psi2 = psi0_lin + psi0_rbf, psi1_lin + psi1_rbf, psi2_lin + psi2_rbf

    # extra terms for the 'interaction' of linear and rbf
    l2 = tf.square(kern.rbf.lengthscales)
    A = tf.expand_dims(1./S + 1./l2, 1)  # N x 1 x Q
    m = (tf.expand_dims(mu/S, 1) + tf.expand_dims(Z/l2, 0)) / A  # N x M x Q
    mTAZ = tf.reduce_sum(tf.expand_dims(m * kern.linear.variance, 1) *
                         tf.expand_dims(tf.expand_dims(Z, 0), 0), 3)  # N x M x M
    Z2 = tf.reduce_sum(tf.square(Z) / l2, 1)  # M,
    mu2 = tf.reduce_sum(tf.square(mu) / S, 1)  # N
    mAm = tf.reduce_sum(tf.square(m) * A, 2)  # N x M
    exp_term = tf.exp(-(tf.reshape(Z2, (1, -1)) + tf.reshape(mu2, (-1, 1))-mAm) / 2.)  # N x M
    psi2_extra = tf.reduce_sum(kern.rbf.variance *
                               tf.expand_dims(exp_term, 2) *
                               tf.expand_dims(tf.expand_dims(tf.reduce_prod(S, 1), 1), 2) *
                               tf.expand_dims(tf.reduce_prod(A, 2), 1) *
                               mTAZ, 0)

    psi2 = psi2 + psi2_extra + tf.transpose(psi2_extra)
    return psi0, psi1, psi2

def gaussian(y, mu_k, sigma_k):
	y = tf.reshape(y, [batchDim,1,L_out])
	norm = tf.reduce_sum(tf.square(y-mu_k),axis=2)	# sums over the L dimensions -> we get shape (N,K) again
	phi_k = -tf.div(norm, 2*tf.square(sigma_k))		
	phi_k = tf.exp(phi_k)
	phi_k = tf.divide(phi_k, sigma_k)
	return phi_k

def gauss_kl(q_mu, q_sqrt, K):
    """
    Compute the KL divergence from

          q(x) = N(q_mu, q_sqrt^2)
    to
          p(x) = N(0, K)

    We assume multiple independent distributions, given by the columns of
    q_mu and the last dimension of q_sqrt.

    q_mu is a matrix, each column contains a mean.

    q_sqrt is a 3D tensor, each matrix within is a lower triangular square-root
        matrix of the covariance of q.

    K is a positive definite matrix: the covariance of p.
    """
    L = tf.cholesky(K)
    alpha = tf.matrix_triangular_solve(L, q_mu, lower=True)
    KL = 0.5 * tf.reduce_sum(tf.square(alpha))  # Mahalanobis term.
    num_latent = tf.cast(tf.shape(q_sqrt)[2], float_type)
    KL += num_latent * 0.5 * tf.reduce_sum(tf.log(tf.square(tf.diag_part(L))))  # Prior log-det term.
    KL += -0.5 * tf.cast(tf.reduce_prod(tf.shape(q_sqrt)[1:]), float_type)  # constant term
    Lq = tf.matrix_band_part(tf.transpose(q_sqrt, (2, 0, 1)), -1, 0)  # force lower triangle
    KL += -0.5*tf.reduce_sum(tf.log(tf.square(tf.matrix_diag_part(Lq))))  # logdet
    L_tiled = tf.tile(tf.expand_dims(L, 0), tf.pack([tf.shape(Lq)[0], 1, 1]))
    LiLq = tf.matrix_triangular_solve(L_tiled, Lq, lower=True)
    KL += 0.5 * tf.reduce_sum(tf.square(LiLq))  # Trace term
    return KL

	def build_rmsprop_optimizer(self, learning_rate, rmsprop_decay, rmsprop_constant, gradient_clip, version):

		with tf.name_scope('rmsprop'):
			optimizer = tf.train.GradientDescentOptimizer(learning_rate)

			grads_and_vars = optimizer.compute_gradients(self.loss)
			grads = [gv[0] for gv in grads_and_vars]
			params = [gv[1] for gv in grads_and_vars]

			if gradient_clip > 0:
				grads = tf.clip_by_global_norm(grads, gradient_clip)

			if version == 'rmsprop':
				return optimizer.apply_gradients(zip(grads, params))
			elif version == 'graves_rmsprop':
				square_grads = [tf.square(grad) for grad in grads]

				avg_grads = [tf.Variable(tf.ones(var.get_shape())) for var in params]
				avg_square_grads = [tf.Variable(tf.ones(var.get_shape())) for var in params]

				update_avg_grads = [grad_pair[0].assign((rmsprop_decay * grad_pair[0]) + ((1 - rmsprop_decay) * grad_pair[1])) 
					for grad_pair in zip(avg_grads, grads)]
				update_avg_square_grads = [grad_pair[0].assign((rmsprop_decay * grad_pair[0]) + ((1 - rmsprop_decay) * tf.square(grad_pair[1]))) 
					for grad_pair in zip(avg_square_grads, grads)]
				avg_grad_updates = update_avg_grads + update_avg_square_grads

				rms = [tf.sqrt(avg_grad_pair[1] - tf.square(avg_grad_pair[0]) + rmsprop_constant)
					for avg_grad_pair in zip(avg_grads, avg_square_grads)]


				rms_updates = [grad_rms_pair[0] / grad_rms_pair[1] for grad_rms_pair in zip(grads, rms)]
				train = optimizer.apply_gradients(zip(rms_updates, params))

				return tf.group(train, tf.group(*avg_grad_updates))

def gauss_kl(q_mu, q_sqrt, K, num_latent):
    """
    Compute the KL divergence from

          q(x) = N(q_mu, q_sqrt^2)
    to
          p(x) = N(0, K)

    We assume num_latent independent distributions, given by the columns of
    q_mu and the last dimension of q_sqrt.

    q_mu is a matrix, each column contains a mean.

    q_sqrt is a 3D tensor, each matrix within is a lower triangular square-root
        matrix of the covariance of q.

    K is a positive definite matrix: the covariance of p.

    num_latent is an integer: the number of independent distributions (equal to
        the columns of q_mu and the last dim of q_sqrt).
    """
    L = tf.cholesky(K)
    alpha = tf.matrix_triangular_solve(L, q_mu, lower=True)
    KL = 0.5 * tf.reduce_sum(tf.square(alpha))  # Mahalanobis term.
    KL += num_latent * 0.5 * tf.reduce_sum(
        tf.log(tf.square(tf.diag_part(L))))  # Prior log-det term.
    KL += -0.5 * tf.cast(tf.shape(q_sqrt)[0] * num_latent, tf.float64)
    for d in range(num_latent):
        Lq = tf.batch_matrix_band_part(q_sqrt[:, :, d], -1, 0)
        # Log determinant of q covariance:
        KL += -0.5*tf.reduce_sum(tf.log(tf.square(tf.diag_part(Lq))))
        LiLq = tf.matrix_triangular_solve(L, Lq, lower=True)
        KL += 0.5 * tf.reduce_sum(tf.square(LiLq))  # Trace term
    return KL

	def build_loss(self, error_clip, num_actions, double_dqn):
		''' build loss graph '''
		with tf.name_scope("loss"):

			predictions = tf.reduce_sum(tf.mul(self.gpu_q_layer, self.actions), 1)
			
			max_action_values = None
			if double_dqn: # Double Q-Learning:
				max_actions = tf.to_int32(tf.argmax(self.gpu_q_layer, 1))
				# tf.gather doesn't support multidimensional indexing yet, so we flatten output activations for indexing
				indices = tf.range(0, tf.size(max_actions) * num_actions, num_actions) + max_actions
				max_action_values = tf.gather(tf.reshape(self.target_q_layer, shape=[-1]), indices)
			else:
				max_action_values = tf.reduce_max(self.target_q_layer, 1)

			targets = tf.stop_gradient(self.rewards + (self.discount_factor * max_action_values * self.terminals))

			difference = tf.abs(predictions - targets)

			if error_clip >= 0:
				quadratic_part = tf.clip_by_value(difference, 0.0, error_clip)
				linear_part = difference - quadratic_part
				errors = (0.5 * tf.square(quadratic_part)) + (error_clip * linear_part)
			else:
				errors = (0.5 * tf.square(difference))

			return tf.reduce_sum(errors)

        def __graph__():
            """Building the inference graph"""

            with tf.name_scope('input'):
                # [BATCH_SIZE, NUM_FEATURES]
                x_input = tf.placeholder(dtype=tf.float32, shape=[None, self.num_features], name='x_input')

                # [BATCH_SIZE]
                y_input = tf.placeholder(dtype=tf.uint8, shape=[None], name='y_input')

                # [BATCH_SIZE, NUM_CLASSES]
                y_onehot = tf.one_hot(indices=y_input, depth=self.num_classes, on_value=1, off_value=-1,
                                      name='y_onehot')

            learning_rate = tf.placeholder(dtype=tf.float32, name='learning_rate')

            with tf.name_scope('training_ops'):
                with tf.name_scope('weights'):
                    weight = tf.get_variable(name='weights',
                                             initializer=tf.random_normal([self.num_features, self.num_classes],
                                                                          stddev=0.01))
                    self.variable_summaries(weight)
                with tf.name_scope('biases'):
                    bias = tf.get_variable(name='biases', initializer=tf.constant([0.1], shape=[self.num_classes]))
                    self.variable_summaries(bias)
                with tf.name_scope('Wx_plus_b'):
                    output = tf.matmul(x_input, weight) + bias
                    tf.summary.histogram('pre-activations', output)

            with tf.name_scope('svm'):
                regularization = tf.reduce_mean(tf.square(weight))
                hinge_loss = tf.reduce_mean(tf.square(tf.maximum(tf.zeros([self.batch_size, self.num_classes]),
                                                                 1 - tf.cast(y_onehot, tf.float32) * output)))
                with tf.name_scope('loss'):
                    loss = regularization + self.svm_c * hinge_loss
            tf.summary.scalar('loss', loss)

            optimizer = tf.train.AdamOptimizer(learning_rate=learning_rate).minimize(loss)

            with tf.name_scope('accuracy'):
                predicted_class = tf.sign(output)
                predicted_class = tf.identity(predicted_class, name='prediction')
                with tf.name_scope('correct_prediction'):
                    correct = tf.equal(tf.argmax(predicted_class, 1), tf.argmax(y_onehot, 1))
                with tf.name_scope('accuracy'):
                    accuracy = tf.reduce_mean(tf.cast(correct, 'float'))
            tf.summary.scalar('accuracy', accuracy)

            merged = tf.summary.merge_all()

            self.x_input = x_input
            self.y_input = y_input
            self.y_onehot = y_onehot
            self.learning_rate = learning_rate
            self.loss = loss
            self.optimizer = optimizer
            self.output = output
            self.predicted_class = predicted_class
            self.accuracy = accuracy
            self.merged = merged

    def _build_loss(self):

        with tf.variable_scope("loss"):

            # Compute y_j = r_j * discount*best_qvalue
            self.tf_discount = tf.constant(self.discount)
            self.qtarget = tf.add(self.pl_rewards, tf.mul(1.0-self.pl_terminals, tf.mul(self.tf_discount, self.pl_qtargets)))

            # Select Q-values for given actions
            self.actions_one_hot = tf.one_hot(self.pl_actions, self.num_actions, 1.0, 0.0)
            self.qvalue_pred = tf.reduce_sum(tf.mul(self.qvalues, self.actions_one_hot), reduction_indices=1)

            # Difference between target and predicted Q-network output
            self.delta = tf.sub(self.qtarget, self.qvalue_pred)

            if self.clip_delta > 0:
                # Perform clipping of the error term, default clipping is to (-1, +1) range
                self.quadratic_part = tf.minimum(tf.abs(self.delta), tf.constant(self.clip_delta))
                self.linear_part    = tf.sub(tf.abs(self.delta), self.quadratic_part)
                self.delta_square   = tf.mul(tf.constant(0.5), tf.square(self.quadratic_part)) + (self.clip_delta*self.linear_part)
                #self.delta_clipped = tf.clip_by_value(self.delta, -1.0*self.clip_delta, self.clip_delta)
                #self.delta_square  = tf.square(self.delta_clipped)
            else:
                # No error clipping
                self.delta_square  = tf.square(self.delta)

        # Actual loss
        if self.batch_accumulator == "sum":
           self.loss = tf.reduce_sum(self.delta_square)
        else:
           self.loss = tf.reduce_mean(self.delta_square)

        # Running average of the loss for TensorBoard
        self.loss_moving_avg    = tf.train.ExponentialMovingAverage(decay=0.999)
        self.loss_moving_avg_op = self.loss_moving_avg.apply([self.loss])

def batchnormalize(X, eps=1e-8, g=None, b=None):
    if X.get_shape().ndims == 4:
        mean = tf.reduce_mean(X, [0,1,2])
        std = tf.reduce_mean( tf.square(X-mean), [0,1,2] )
        X = (X-mean) / tf.sqrt(std+eps)

        if g is not None and b is not None:
            g = tf.reshape(g, [1,1,1,-1])
            b = tf.reshape(b, [1,1,1,-1])
            X = X*g + b

    elif X.get_shape().ndims == 2:
        mean = tf.reduce_mean(X, 0)
        std = tf.reduce_mean(tf.square(X-mean), 0)
        X = (X-mean) / tf.sqrt(std+eps)#std

        if g is not None and b is not None:
            g = tf.reshape(g, [1,-1])
            b = tf.reshape(b, [1,-1])
            X = X*g + b

    else:
        raise NotImplementedError

    return X