# Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserve. # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. """ All layers just related to the neural network. """ from ..layer_helper import LayerHelper from ..initializer import Normal, Constant from ..framework import Variable from ..param_attr import ParamAttr from layer_function_generator import autodoc from tensor import concat __all__ = [ 'fc', 'embedding', 'dynamic_lstm', 'dynamic_gru', 'gru_unit', 'linear_chain_crf', 'crf_decoding', 'cos_sim', 'cross_entropy', 'square_error_cost', 'accuracy', 'chunk_eval', 'sequence_conv', 'conv2d', 'sequence_pool', 'pool2d', 'batch_norm', 'beam_search_decode', 'conv2d_transpose', 'sequence_expand', 'lstm_unit', 'reduce_sum', 'reduce_mean', 'reduce_max', 'reduce_min', 'sequence_first_step', 'sequence_last_step', 'dropout', 'split', 'ctc_greedy_decoder', 'edit_distance', 'l2_normalize', 'matmul', 'warpctc', 'sequence_reshape', 'transpose', 'im2sequence', 'nce', ] def fc(input, size, num_flatten_dims=1, param_attr=None, bias_attr=None, act=None, name=None): """ **Fully Connected Layer** The fully connected layer can take multiple tensors as its inputs. It creates a variable (one for each input tensor) called weights for each input tensor, which represents a fully connected weight matrix from each input unit to each output unit. The fully connected layer multiplies each input tensor with its coresponding weight to produce an output Tensor. If multiple input tensors are given, the results of multiple multiplications will be sumed up. If bias_attr is not None, a biases variable will be created and added to the output. Finally, if activation is not None, it will be applied to the output as well. This process can be formulated as follows: .. math:: Out = Act({\sum_{i=0}^{N-1}W_iX_i + b}) In the above equation: * :math:`N`: Number of the input. * :math:`X_i`: The input tensor. * :math:`W`: The weights created by this layer. * :math:`b`: The bias parameter created by this layer (if needed). * :math:`Act`: The activation funtion. * :math:`Out`: The output tensor. Args: input(Variable|list): The input tensor(s) to the fully connected layer. size(int): The number of output units in the fully connected layer. num_flatten_dims(int): The fc layer can accept an input tensor with more than two dimensions. If this happens, the multidimensional tensor will first be flattened into a 2-dimensional matrix. The parameter `num_flatten_dims` determines how the input tensor is flattened: the first `num_flatten_dims` dimensions will be flatten to form the first dimension of the final matrix (height of the matrix), and the rest `rank(X) - num_flatten_dims` dimensions are flattened to form the second dimension of the final matrix (width of the matrix). For example, suppose `X` is a 6-dimensional tensor with a shape [2, 3, 4, 5, 6], and `num_flatten_dims` = 3. Then, the flattened matrix will have a shape [2 x 3 x 4, 5 x 6] = [24, 30]. By default, `num_flatten_dims` is set to 1. param_attr(ParamAttr|list): The parameter attribute for learnable parameters/weights of the fully connected layer. param_initializer(ParamAttr|list): The initializer used for the weight/parameter. If set None, XavierInitializer() will be used. bias_attr(ParamAttr|list): The parameter attribute for the bias parameter for this layer. If set None, no bias will be added to the output units. bias_initializer(ParamAttr|list): The initializer used for the bias. If set None, then ConstantInitializer() will be used. act(str): Activation to be applied to the output of the fully connected layer. name(str): Name/alias of the fully connected layer. Returns: Variable: The output tensor variable. Raises: ValueError: If rank of the input tensor is less than 2. Examples: .. code-block:: python data = fluid.layers.data(name="data", shape=[32, 32], dtype="float32") fc = fluid.layers.fc(input=data, size=1000, act="tanh") """ helper = LayerHelper("fc", **locals()) dtype = helper.input_dtype() mul_results = [] for input_var, param_attr in helper.iter_inputs_and_params(): input_shape = input_var.shape param_shape = [ reduce(lambda a, b: a * b, input_shape[num_flatten_dims:], 1) ] + [size] w = helper.create_parameter( attr=param_attr, shape=param_shape, dtype=dtype, is_bias=False) tmp = helper.create_tmp_variable(dtype) helper.append_op( type="mul", inputs={ "X": input_var, "Y": w, }, outputs={"Out": tmp}, attrs={"x_num_col_dims": num_flatten_dims, "y_num_col_dims": 1}) mul_results.append(tmp) # sum if len(mul_results) == 1: pre_bias = mul_results[0] else: pre_bias = helper.create_tmp_variable(dtype) helper.append_op( type="sum", inputs={"X": mul_results}, outputs={"Out": pre_bias}) # add bias pre_activation = helper.append_bias_op(pre_bias) # add activation return helper.append_activation(pre_activation) def embedding(input, size, is_sparse=False, param_attr=None, dtype='float32'): """ **Embedding Layer** This layer is used to lookup a vector of IDs, provided by *input*, in a lookup table. The result of this lookup is the embedding of each ID in the *input*. All the input variables are passed in as local variables to the LayerHelper constructor. Args: input(Variable): Input to the function size(tuple|list|None): Shape of the look up table parameter is_sparse(bool): Boolean flag that specifying whether the input is sparse param_attr(ParamAttr): Parameters for this layer dtype(np.dtype|core.DataType|str): The type of data : float32, float_16, int etc Returns: Variable: The tensor variable storing the embeddings of the \ supplied inputs. Examples: .. code-block:: python dict_size = len(dataset.ids) data = fluid.layers.data(name='ids', shape=[32, 32], dtype='float32') fc = fluid.layers.embedding(input=data, size=[dict_size, 16]) """ helper = LayerHelper('embedding', **locals()) w = helper.create_parameter( attr=helper.param_attr, shape=size, dtype=dtype, is_bias=False) tmp = helper.create_tmp_variable(dtype) helper.append_op( type='lookup_table', inputs={'Ids': input, 'W': w}, outputs={'Out': tmp}, attrs={'is_sparse': is_sparse}) return tmp # TODO(qijun): expose H0 and C0 def dynamic_lstm(input, size, param_attr=None, bias_attr=None, use_peepholes=True, is_reverse=False, gate_activation='sigmoid', cell_activation='tanh', candidate_activation='tanh', dtype='float32'): """ **Dynamic LSTM Layer** The defalut implementation is diagonal/peephole connection (https://arxiv.org/pdf/1402.1128.pdf), the formula is as follows: .. math:: i_t & = \sigma(W_{ix}x_{t} + W_{ih}h_{t-1} + W_{ic}c_{t-1} + b_i) f_t & = \sigma(W_{fx}x_{t} + W_{fh}h_{t-1} + W_{fc}c_{t-1} + b_f) \\tilde{c_t} & = act_g(W_{cx}x_t + W_{ch}h_{t-1} + b_c) o_t & = \sigma(W_{ox}x_{t} + W_{oh}h_{t-1} + W_{oc}c_t + b_o) c_t & = f_t \odot c_{t-1} + i_t \odot \\tilde{c_t} h_t & = o_t \odot act_h(c_t) where the :math:`W` terms denote weight matrices (e.g. :math:`W_{xi}` is the matrix of weights from the input gate to the input), :math:`W_{ic}, \ W_{fc}, W_{oc}` are diagonal weight matrices for peephole connections. In our implementation, we use vectors to reprenset these diagonal weight matrices. The :math:`b` terms denote bias vectors (:math:`b_i` is the input gate bias vector), :math:`\sigma` is the non-line activations, such as logistic sigmoid function, and :math:`i, f, o` and :math:`c` are the input gate, forget gate, output gate, and cell activation vectors, respectively, all of which have the same size as the cell output activation vector :math:`h`. The :math:`\odot` is the element-wise product of the vectors. :math:`act_g` and :math:`act_h` are the cell input and cell output activation functions and `tanh` is usually used for them. :math:`\\tilde{c_t}` is also called candidate hidden state, which is computed based on the current input and the previous hidden state. Set `use_peepholes` to `False` to disable peephole connection. The formula is omitted here, please refer to the paper http://www.bioinf.jku.at/publications/older/2604.pdf for details. Note that these :math:`W_{xi}x_{t}, W_{xf}x_{t}, W_{xc}x_{t}, W_{xo}x_{t}` operations on the input :math:`x_{t}` are NOT included in this operator. Users can choose to use fully-connect layer before LSTM layer. Args: input(Variable): The input of dynamic_lstm layer, which supports variable-time length input sequence. The underlying tensor in this Variable is a matrix with shape (T X 4D), where T is the total time steps in this mini-batch, D is the hidden size. size(int): 4 * hidden size. param_attr(ParamAttr): The parameter attribute for the learnable hidden-hidden weights. - The shape is (D x 4D), where D is the hidden size. - Weights = {:math:`W_{ch}, W_{ih}, \ W_{fh}, W_{oh}`} bias_attr(ParamAttr): The bias attribute for the learnable bias weights, which contains two parts, input-hidden bias weights and peephole connections weights if setting `use_peepholes` to `True`. 1. `use_peepholes = False` - The shape is (1 x 4D). - Biases = {:math:`b_c, b_i, b_f, b_o`}. 2. `use_peepholes = True` - The shape is (1 x 7D). - Biases = { :math:`b_c, b_i, b_f, b_o, W_{ic}, \ W_{fc}, W_{oc}`}. use_peepholes(bool): Whether to enable diagonal/peephole connections, default `True`. is_reverse(bool): Whether to compute reversed LSTM, default `False`. gate_activation(str): The activation for input gate, forget gate and output gate. Choices = ["sigmoid", "tanh", "relu", "identity"], default "sigmoid". cell_activation(str): The activation for cell output. Choices = ["sigmoid", "tanh", "relu", "identity"], default "tanh". candidate_activation(str): The activation for candidate hidden state. Choices = ["sigmoid", "tanh", "relu", "identity"], default "tanh". dtype(str): Data type. Choices = ["float32", "float64"], default "float32". Returns: tuple: The hidden state, and cell state of LSTM. The shape of both \ is (T x D), and lod is the same with the `input`. Examples: .. code-block:: python hidden_dim = 512 forward_proj = fluid.layers.fc(input=input_seq, size=hidden_dim * 4, act=None, bias_attr=None) forward, _ = fluid.layers.dynamic_lstm( input=forward_proj, size=hidden_dim * 4, use_peepholes=False) """ helper = LayerHelper('lstm', **locals()) size = size / 4 weight = helper.create_parameter( attr=helper.param_attr, shape=[size, 4 * size], dtype=dtype) bias_size = [1, 7 * size] if not use_peepholes: bias_size[1] = 4 * size bias = helper.create_parameter( attr=helper.bias_attr, shape=bias_size, dtype=dtype, is_bias=True) hidden = helper.create_tmp_variable(dtype) cell = helper.create_tmp_variable(dtype) batch_gate = helper.create_tmp_variable(dtype) batch_cell_pre_act = helper.create_tmp_variable(dtype) helper.append_op( type='lstm', inputs={'Input': input, 'Weight': weight, 'Bias': bias}, outputs={ 'Hidden': hidden, 'Cell': cell, 'BatchGate': batch_gate, 'BatchCellPreAct': batch_cell_pre_act }, attrs={ 'use_peepholes': use_peepholes, 'is_reverse': is_reverse, 'gate_activation': gate_activation, 'cell_activation': cell_activation, 'candidate_activation': candidate_activation }) return hidden, cell def dynamic_gru(input, size, param_attr=None, bias_attr=None, is_reverse=False, gate_activation='sigmoid', candidate_activation='tanh', h_0=None): """ **Dynamic GRU Layer** Refer to `Empirical Evaluation of Gated Recurrent Neural Networks on Sequence Modeling `_ The formula is as follows: .. math:: u_t & = act_g(W_{ux}x_{t} + W_{uh}h_{t-1} + b_u) r_t & = act_g(W_{rx}x_{t} + W_{rh}h_{t-1} + b_r) \\tilde{h_t} & = act_c(W_{cx}x_{t} + W_{ch}(r_t \odot h_{t-1}) + b_c) h_t & = (1-u_t) \odot h_{t-1} + u_t \odot \\tilde{h_t} The :math:`\odot` is the element-wise product of the vectors. :math:`act_g` is the update gate and reset gate activation function and :math:`sigmoid` is usually used for it. :math:`act_c` is the activation function for candidate hidden state and :math:`tanh` is usually used for it. Note that these :math:`W_{ux}x_{t}, W_{rx}x_{t}, W_{cx}x_{t}` operations on the input :math:`x_{t}` are NOT included in this operator. Users can choose to use fully-connect layer before GRU layer. Args: input(Variable): The input of dynamic_gru layer, which supports variable-time length input sequence. The underlying tensor in this Variable is a matrix with shape :math:`(T \\times 3D)`, where :math:`T` is the total time steps in this mini-batch, :math:`D` is the hidden size. size(int): The dimension of the gru cell. param_attr(ParamAttr|None): The parameter attribute for the learnable hidden-hidden weight matrix. Note: - The shape of the weight matrix is :math:`(T \\times 3D)`, where :math:`D` is the hidden size. - All elements in the weight matrix can be divided into two parts. The first part are weights of the update gate and reset gate with shape :math:`(D \\times 2D)`, and the second part are weights for candidate hidden state with shape :math:`(D \\times D)`. bias_attr(ParamAttr): The parameter attribute for learnable the hidden-hidden bias. is_reverse(bool): Whether to compute reversed GRU, default :attr:`False`. gate_activation(str): The activation for update gate and reset gate. Choices = ["sigmoid", "tanh", "relu", "identity"], default "sigmoid". activation(str): The activation for candidate hidden state. Choices = ["sigmoid", "tanh", "relu", "identity"], default "tanh". Returns: Variable: The hidden state of GRU. The shape is (T \\times D), and lod \ is the same with the input. Examples: .. code-block:: python hidden_dim = 512 x = fluid.layers.fc(input=data, size=hidden_dim * 3) hidden = fluid.layers.dynamic_gru(input=x, dim=hidden_dim) """ helper = LayerHelper('gru', **locals()) dtype = helper.input_dtype() weight = helper.create_parameter( attr=helper.param_attr, shape=[size, 3 * size], dtype=dtype) bias = helper.create_parameter( attr=helper.bias_attr, shape=[1, 3 * size], dtype=dtype, is_bias=True) inputs = {'Input': input, 'Weight': weight, 'Bias': bias} if h_0 != None: assert h_0.shape == ( size, size), 'The shape of h0 should be(%d, %d)' % (size, size) inputs['h0'] = h_0 hidden = helper.create_tmp_variable(dtype) batch_gate = helper.create_tmp_variable(dtype) batch_reset_hidden_prev = helper.create_tmp_variable(dtype) batch_hidden = helper.create_tmp_variable(dtype) helper.append_op( type='gru', inputs=inputs, outputs={ 'Hidden': hidden, 'BatchGate': batch_gate, 'BatchResetHiddenPrev': batch_reset_hidden_prev, 'BatchHidden': batch_hidden }, attrs={ 'is_reverse': is_reverse, 'gate_activation': gate_activation, 'activation': candidate_activation }) return hidden def gru_unit(input, hidden, size, weight=None, bias=None, activation='tanh', gate_activation='sigmoid'): """ GRU unit layer. The equation of a gru step is: .. math:: u_t & = actGate(xu_{t} + W_u h_{t-1} + b_u) r_t & = actGate(xr_{t} + W_r h_{t-1} + b_r) m_t & = actNode(xm_t + W_c dot(r_t, h_{t-1}) + b_m) h_t & = dot((1-u_t), m_t) + dot(u_t, h_{t-1}) The inputs of gru unit includes :math:`z_t`, :math:`h_{t-1}`. In terms of the equation above, the :math:`z_t` is split into 3 parts - :math:`xu_t`, :math:`xr_t` and :math:`xm_t`. This means that in order to implement a full GRU unit operator for an input, a fully connected layer has to be applied, such that :math:`z_t = W_{fc}x_t`. The terms :math:`u_t` and :math:`r_t` represent the update and reset gates of the GRU cell. Unlike LSTM, GRU has one lesser gate. However, there is an intermediate candidate hidden output, which is denoted by :math:`m_t`. This layer has three outputs :math:`h_t`, :math:`dot(r_t, h_{t-1})` and concatenation of :math:`u_t`, :math:`r_t` and :math:`m_t`. Args: input (Variable): The fc transformed input value of current step. hidden (Variable): The hidden value of lstm unit from previous step. size (integer): The input dimension value. weight (ParamAttr): The weight parameters for gru unit. Default: None bias (ParamAttr): The bias parameters for gru unit. Default: None activation (string): The activation type for cell (actNode). Default: 'tanh' gate_activation (string): The activation type for gates (actGate). Default: 'sigmoid' Returns: tuple: The hidden value, reset-hidden value and gate values. Examples: .. code-block:: python # assuming we have x_t_data and prev_hidden of size=10 x_t = fluid.layers.fc(input=x_t_data, size=30) hidden_val, r_h_val, gate_val = fluid.layers.gru_unit(input=x_t, hidden = prev_hidden) """ activation_dict = dict( identity=0, sigmoid=1, tanh=2, relu=3, ) activation = activation_dict[activation] gate_activation = activation_dict[gate_activation] helper = LayerHelper('gru_unit', **locals()) dtype = helper.input_dtype() size = size / 3 # create weight if weight is None: weight = helper.create_parameter( attr=helper.param_attr, shape=[size, 3 * size], dtype=dtype) # create bias if bias is None: bias_size = [1, 3 * size] bias = helper.create_parameter( attr=helper.bias_attr, shape=bias_size, dtype=dtype, is_bias=True) gate = helper.create_tmp_variable(dtype) reset_hidden_pre = helper.create_tmp_variable(dtype) updated_hidden = helper.create_tmp_variable(dtype) helper.append_op( type='gru_unit', inputs={'Input': input, 'HiddenPrev': hidden, 'Weight': weight}, outputs={ 'Gate': gate, 'ResetHiddenPrev': reset_hidden_pre, 'Hidden': updated_hidden, }, attrs={ 'activation': 0, 'gate_activation': 1, }) return updated_hidden, reset_hidden_pre, gate def linear_chain_crf(input, label, param_attr=None): helper = LayerHelper('linear_chain_crf', **locals()) size = input.shape[1] transition = helper.create_parameter( attr=helper.param_attr, shape=[size + 2, size], dtype=helper.input_dtype()) alpha = helper.create_tmp_variable(dtype=helper.input_dtype()) emission_exps = helper.create_tmp_variable(dtype=helper.input_dtype()) transition_exps = helper.create_tmp_variable(dtype=helper.input_dtype()) log_likelihood = helper.create_tmp_variable(dtype=helper.input_dtype()) helper.append_op( type='linear_chain_crf', inputs={"Emission": [input], "Transition": transition, "Label": label}, outputs={ "Alpha": [alpha], "EmissionExps": [emission_exps], "TransitionExps": transition_exps, "LogLikelihood": log_likelihood }) return log_likelihood def crf_decoding(input, param_attr, label=None): helper = LayerHelper('crf_decoding', **locals()) transition = helper.get_parameter(param_attr.name) viterbi_path = helper.create_tmp_variable(dtype=helper.input_dtype()) helper.append_op( type='crf_decoding', inputs={"Emission": [input], "Transition": transition, "Label": label}, outputs={"ViterbiPath": [viterbi_path]}) return viterbi_path def cos_sim(X, Y, **kwargs): """ This function performs the cosine similarity between two tensors X and Y and returns that as the output. """ helper = LayerHelper('cos_sim', **kwargs) out = helper.create_tmp_variable(dtype=X.dtype) xnorm = helper.create_tmp_variable(dtype=X.dtype) ynorm = helper.create_tmp_variable(dtype=X.dtype) helper.append_op( type='cos_sim', inputs={'X': [X], 'Y': [Y]}, outputs={'Out': [out], 'XNorm': [xnorm], 'YNorm': [ynorm]}) return out def dropout(x, dropout_prob, is_test=False, seed=0, **kwargs): helper = LayerHelper('dropout', **kwargs) out = helper.create_tmp_variable(dtype=x.dtype) mask = helper.create_tmp_variable(dtype=x.dtype, stop_gradient=True) helper.append_op( type='dropout', inputs={'X': [x]}, outputs={'Out': [out], 'Mask': [mask]}, attrs={'dropout_prob': dropout_prob, 'is_test': is_test, 'seed': seed}) return out def cross_entropy(input, label, **kwargs): """ **Cross Entropy Layer** This layer computes the cross entropy between `input` and `label`. It supports both standard cross-entropy and soft-label cross-entropy loss computation. 1) One-hot cross-entropy: `soft_label = False`, `Label[i, 0]` indicates the class index for sample i: .. math:: Y[i] = -\log(X[i, Label[i]]) 2) Soft-label cross-entropy: `soft_label = True`, `Label[i, j]` indicates the soft label of class j for sample i: .. math:: Y[i] = \sum_j{-Label[i, j] * log(X[i, j])} Please make sure that in this case the summation of each row of `label` equals one. 3) One-hot cross-entropy with vecterized `label`: As a special case of 2), when each row of 'label' has only one non-zero element which is equal to 1, soft-label cross-entropy degenerates to a one-hot cross-entropy with one-hot label representation. Args: input (Variable|list): a 2-D tensor with shape [N x D], where N is the batch size and D is the number of classes. This input is a probability computed by the previous operator, which is almost always the result of a softmax operator. label (Variable|list): the ground truth which is a 2-D tensor. When `soft_label` is set to `False`, `label` is a tensor with shape [N x 1]. When `soft_label` is set to `True`, `label` is a tensor with shape [N x D]. soft_label (bool, via `**kwargs`): a flag indicating whether to interpretate the given labels as soft labels, default `False`. Returns: A 2-D tensor with shape [N x 1], the cross entropy loss. Raises: `ValueError`: 1) the 1st dimension of `input` and `label` are not equal; 2) when \ `soft_label == True`, and the 2nd dimension of `input` and `label` are not \ equal; 3) when `soft_label == False`, and the 2nd dimension of `label` is not 1. Examples: .. code-block:: python predict = fluid.layers.fc(input=net, size=classdim, act='softmax') cost = fluid.layers.cross_entropy(input=predict, label=label) """ helper = LayerHelper('cross_entropy', **kwargs) out = helper.create_tmp_variable(dtype=input.dtype) helper.append_op( type='cross_entropy', inputs={'X': [input], 'Label': [label]}, outputs={'Y': [out]}, attrs=kwargs) return out def square_error_cost(input, label, **kwargs): """ **Square error cost layer** This layer accepts input predictions and target label and returns the squared error cost. For predictions, :math:`X`, and target labels, :math:`Y`, the equation is: .. math:: Out = (X - Y)^2 In the above equation: * :math:`X`: Input predictions, a tensor. * :math:`Y`: Input labels, a tensor. * :math:`Out`: Output value, same shape with :math:`X`. Args: input(Variable): Input tensor, has predictions. label(Variable): Label tensor, has target labels. Returns: Variable: The tensor variable storing the element-wise squared error difference \ of input and label. Examples: .. code-block:: python y = layers.data(name='y', shape=[1], dtype='float32') y_predict = layers.data(name='y_predict', shape=[1], dtype='float32') cost = layers.square_error_cost(input=y_predict, label=y) """ helper = LayerHelper('square_error_cost', **kwargs) minus_out = helper.create_tmp_variable(dtype=input.dtype) helper.append_op( type='elementwise_sub', inputs={'X': [input], 'Y': [label]}, outputs={'Out': [minus_out]}) square_out = helper.create_tmp_variable(dtype=input.dtype) helper.append_op( type='square', inputs={'X': [minus_out]}, outputs={'Out': [square_out]}) return square_out def accuracy(input, label, k=1, correct=None, total=None, **kwargs): """ This function computes the accuracy using the input and label. The output is the top_k inputs and their indices. """ helper = LayerHelper("accuracy", **kwargs) topk_out = helper.create_tmp_variable(dtype=input.dtype) topk_indices = helper.create_tmp_variable(dtype="int64") helper.append_op( type="top_k", inputs={"X": [input]}, outputs={"Out": [topk_out], "Indices": [topk_indices]}, attrs={"k": k}) acc_out = helper.create_tmp_variable(dtype="float32") if correct is None: correct = helper.create_tmp_variable(dtype="int64") if total is None: total = helper.create_tmp_variable(dtype="int64") helper.append_op( type="accuracy", inputs={ "Out": [topk_out], "Indices": [topk_indices], "Label": [label] }, outputs={ "Accuracy": [acc_out], "Correct": [correct], "Total": [total], }) return acc_out def chunk_eval(input, label, chunk_scheme, num_chunk_types, excluded_chunk_types=None, **kwargs): """ This function computes and outputs the precision, recall and F1-score of chunk detection. """ helper = LayerHelper("chunk_eval", **kwargs) # prepare output precision = helper.create_tmp_variable(dtype="float32") recall = helper.create_tmp_variable(dtype="float32") f1_score = helper.create_tmp_variable(dtype="float32") num_infer_chunks = helper.create_tmp_variable(dtype="int64") num_label_chunks = helper.create_tmp_variable(dtype="int64") num_correct_chunks = helper.create_tmp_variable(dtype="int64") helper.append_op( type="chunk_eval", inputs={"Inference": [input], "Label": [label]}, outputs={ "Precision": [precision], "Recall": [recall], "F1-Score": [f1_score], "NumInferChunks": [num_infer_chunks], "NumLabelChunks": [num_label_chunks], "NumCorrectChunks": [num_correct_chunks] }, attrs={ "num_chunk_types": num_chunk_types, "chunk_scheme": chunk_scheme, "excluded_chunk_types": excluded_chunk_types or [] }) return precision, recall, f1_score, num_infer_chunks, num_label_chunks, num_correct_chunks def sequence_conv(input, num_filters, filter_size=3, filter_stride=1, padding=None, bias_attr=None, param_attr=None, act=None): """ This function creates the op for sequence_conv, using the inputs and other convolutional configurations for the filters and stride as given in the input parameters to the function. """ # FIXME(dzh) : want to unify the argument of python layer # function. So we ignore some unecessary attributes. # such as, padding_trainable, context_start. helper = LayerHelper('sequence_conv', **locals()) dtype = helper.input_dtype() filter_shape = [filter_size * input.shape[1], num_filters] filter_param = helper.create_parameter( attr=helper.param_attr, shape=filter_shape, dtype=dtype) pre_bias = helper.create_tmp_variable(dtype) helper.append_op( type='sequence_conv', inputs={ 'X': [input], 'Filter': [filter_param], }, outputs={"Out": pre_bias}, attrs={ 'contextStride': filter_stride, 'contextStart': -int(filter_size / 2), 'contextLength': filter_size }) pre_act = helper.append_bias_op(pre_bias) return helper.append_activation(pre_act) def conv2d(input, num_filters, filter_size, stride=None, padding=None, groups=None, param_attr=None, bias_attr=None, use_cudnn=True, act=None): """ **Convlution2D Layer** The convolution2D layer calculates the output based on the input, filter and strides, paddings, dilations, groups parameters. Input(Input) and Output(Output) are in NCHW format. Where N is batch size, C is the number of channels, H is the height of the feature, and W is the width of the feature. The details of convolution layer, please refer UFLDL's `convolution, `_ . If bias attribution and activation type are provided, bias is added to the output of the convolution, and the corresponding activation function is applied to the final result. For each input :math:`X`, the equation is: .. math:: Out = \sigma (W \\ast X + b) In the above equation: * :math:`X`: Input value, a tensor with NCHW format. * :math:`W`: Filter value, a tensor with MCHW format. * :math:`\\ast`: Convolution operation. * :math:`b`: Bias value, a 2-D tensor with shape [M, 1]. * :math:`\\sigma`: Activation function. * :math:`Out`: Output value, the shape of :math:`Out` and :math:`X` may be different. Example: - Input: Input shape: $(N, C_{in}, H_{in}, W_{in})$ Filter shape: $(C_{out}, C_{in}, H_f, W_f)$ - Output: Output shape: $(N, C_{out}, H_{out}, W_{out})$ Where .. math:: H_{out}&= \\frac{(H_{in} + 2 * paddings[0] - (dilations[0] * (H_f - 1) + 1))}{strides[0]} + 1 \\\\ W_{out}&= \\frac{(W_{in} + 2 * paddings[1] - (dilations[1] * (W_f - 1) + 1))}{strides[1]} + 1 Args: input(Variable): The input image with [N, C, H, W] format. num_filters(int): The number of filter. It is as same as the output image channel. filter_size(int|tuple|None): The filter size. If filter_size is a tuple, it must contain two integers, (filter_size_H, filter_size_W). Otherwise, the filter will be a square. stride(int|tuple): The stride size. If stride is a tuple, it must contain two integers, (stride_H, stride_W). Otherwise, the stride_H = stride_W = stride. Default: stride = 1. padding(int|tuple): The padding size. If padding is a tuple, it must contain two integers, (padding_H, padding_W). Otherwise, the padding_H = padding_W = padding. Default: padding = 0. groups(int): The groups number of the Conv2d Layer. According to grouped convolution in Alex Krizhevsky's Deep CNN paper: when group=2, the first half of the filters is only connected to the first half of the input channels, while the second half of the filters is only connected to the second half of the input channels. Default: groups=1 param_attr(ParamAttr): The parameters to the Conv2d Layer. Default: None bias_attr(ParamAttr): Bias parameter for the Conv2d layer. Default: None use_cudnn(bool): Use cudnn kernel or not, it is valid only when the cudnn library is installed. Default: True act(str): Activation type. Default: None Returns: Variable: The tensor variable storing the convolution and \ non-linearity activation result. Raises: ValueError: If the shapes of input, filter_size, stride, padding and groups mismatch. Examples: .. code-block:: python data = fluid.layers.data(name='data', shape=[3, 32, 32], dtype='float32') conv2d = fluid.layers.conv2d(input=data, num_filters=2, filter_size=3, act="relu") """ if stride is None: stride = [1, 1] helper = LayerHelper('conv2d', **locals()) dtype = helper.input_dtype() num_channels = input.shape[1] if groups is None: num_filter_channels = num_channels else: if num_channels % groups != 0: raise ValueError("num_channels must be divisible by groups.") num_filter_channels = num_channels / groups if isinstance(filter_size, int): filter_size = [filter_size, filter_size] if isinstance(stride, int): stride = [stride, stride] if isinstance(padding, int): padding = [padding, padding] if not isinstance(use_cudnn, bool): raise ValueError("use_cudnn should be True or False") input_shape = input.shape filter_shape = [num_filters, num_filter_channels] + filter_size def _get_default_param_initializer(): std = (2.0 / (filter_size[0]**2 * num_channels))**0.5 return Normal(0.0, std, 0) filter_param = helper.create_parameter( attr=helper.param_attr, shape=filter_shape, dtype=dtype, default_initializer=_get_default_param_initializer()) pre_bias = helper.create_tmp_variable(dtype) helper.append_op( type='conv2d', inputs={ 'Input': input, 'Filter': filter_param, }, outputs={"Output": pre_bias}, attrs={ 'strides': stride, 'paddings': padding, 'groups': groups, 'use_cudnn': use_cudnn }) pre_act = helper.append_bias_op(pre_bias, dim_start=1, dim_end=2) return helper.append_activation(pre_act) def sequence_pool(input, pool_type, **kwargs): """ This function add the operator for sequence pooling. It pools features of all time-steps of each instance, and is applied on top of the input using pool_type mentioned in the parameters. It supports four pool_type: - average: :math:`Out[i] = \\frac{\sum_i X_i}{N}` - sum: :math:`Out[i] = \sum_jX_{ij}` - sqrt: :math:`Out[i] = \\frac{\sum_jX_{ij}}{\sqrt{len(X_i)}}` - max: :math:`Out[i] = max(X_i)` .. code-block:: text x is a 1-level LoDTensor: x.lod = [[0, 2, 5, 7]] x.data = [1, 3, 2, 4, 6, 5, 1] x.dims = [7, 1] then output is a Tensor: out.dim = [3, 1] with condition len(x.lod[-1]) - 1 == out.dims[0] for different pool_type: average: out.data = [2, 4, 3], where 2=(1+3)/2, 4=(2+4+6)/3, 3=(5+1)/2 sum : out.data = [4, 12, 6], where 4=1+3, 12=2+4+6, 6=5+1 sqrt : out.data = [2.82, 6.93, 4.24], where 2.82=(1+3)/sqrt(2), 6.93=(2+4+6)/sqrt(3), 4.24=(5+1)/sqrt(2) max : out.data = [3, 6, 5], where 3=max(1,3), 6=max(2,4,6), 5=max(5,1) Args: input(variable): The input variable which is a LoDTensor. pool_type (string): The pooling type of sequence_pool. It supports average, sum, sqrt and max. Returns: The sequence pooling variable which is a Tensor. Examples: .. code-block:: python x = fluid.layers.data(name='x', shape=[7, 1], dtype='float32', lod_level=1) avg_x = fluid.layers.sequence_pool(input=x, pool_type='average') sum_x = fluid.layers.sequence_pool(input=x, pool_type='sum') sqrt_x = fluid.layers.sequence_pool(input=x, pool_type='sqrt') max_x = fluid.layers.sequence_pool(input=x, pool_type='max') """ helper = LayerHelper('sequence_pool', input=input, **kwargs) dtype = helper.input_dtype() pool_out = helper.create_tmp_variable(dtype) max_index = helper.create_tmp_variable(dtype) helper.append_op( type="sequence_pool", inputs={"X": input}, outputs={"Out": pool_out, "MaxIndex": max_index}, attrs={"pooltype": pool_type.upper()}) # when pool_type is max, variable max_index is initialized, # so we stop the gradient explicitly here if pool_type == 'max': max_index.stop_gradient = True return pool_out def sequence_first_step(input, **kwargs): """ This funciton get the first step of sequence. .. code-block:: text x is a 1-level LoDTensor: x.lod = [[0, 2, 5, 7]] x.data = [1, 3, 2, 4, 6, 5, 1] x.dims = [7, 1] then output is a Tensor: out.dim = [3, 1] with condition len(x.lod[-1]) - 1 == out.dims[0] out.data = [1, 2, 5], where 1=first(1,3), 2=first(2,4,6), 5=first(5,1) Args: input(variable): The input variable which is a LoDTensor. Returns: The sequence's first step variable which is a Tensor. Examples: .. code-block:: python x = fluid.layers.data(name='x', shape=[7, 1], dtype='float32', lod_level=1) x_first_step = fluid.layers.sequence_first_step(input=x) """ return sequence_pool(input=input, pool_type="first") def sequence_last_step(input, **kwargs): """ This funciton get the last step of sequence. .. code-block:: text x is a 1-level LoDTensor: x.lod = [[0, 2, 5, 7]] x.data = [1, 3, 2, 4, 6, 5, 1] x.dims = [7, 1] then output is a Tensor: out.dim = [3, 1] with condition len(x.lod[-1]) - 1 == out.dims[0] out.data = [3, 6, 1], where 3=last(1,3), 6=last(2,4,6), 1=last(5,1) Args: input(variable): The input variable which is a LoDTensor. Returns: The sequence's last step variable which is a Tensor. Examples: .. code-block:: python x = fluid.layers.data(name='x', shape=[7, 1], dtype='float32', lod_level=1) x_last_step = fluid.layers.sequence_last_step(input=x) """ return sequence_pool(input=input, pool_type="last") def pool2d(input, pool_size, pool_type, pool_stride=None, pool_padding=None, global_pooling=False, use_cudnn=True, name=None): """ This function adds the operator for pooling in 2 dimensions, using the pooling configurations mentioned in input parameters. """ if pool_padding is None: pool_padding = [0, 0] if pool_stride is None: pool_stride = [1, 1] if pool_type not in ["max", "avg"]: raise ValueError( "Unknown pool_type: '%s'. It can only be 'max' or 'avg'.", str(pool_type)) if isinstance(pool_size, int): pool_size = [pool_size, pool_size] if isinstance(pool_stride, int): pool_stride = [pool_stride, pool_stride] if isinstance(pool_padding, int): pool_padding = [pool_padding, pool_padding] if not isinstance(use_cudnn, bool): raise ValueError("use_cudnn should be True or False") helper = LayerHelper('pool2d', **locals()) dtype = helper.input_dtype() pool_out = helper.create_tmp_variable(dtype) helper.append_op( type="pool2d", inputs={"X": input}, outputs={"Out": pool_out}, attrs={ "pooling_type": pool_type, "ksize": pool_size, "global_pooling": global_pooling, "strides": pool_stride, "paddings": pool_padding, "use_cudnn": use_cudnn }) return pool_out def batch_norm(input, act=None, is_test=False, momentum=0.9, epsilon=1e-05, param_attr=None, bias_attr=None, data_layout='NCHW', name=None): """ This function helps create an operator to implement the BatchNorm layer using the configurations from the input parameters. """ helper = LayerHelper('batch_norm', **locals()) dtype = helper.input_dtype() input_shape = input.shape if data_layout == 'NCHW': channel_num = input_shape[1] else: if data_layout == 'NHWC': channel_num = input_shape[-1] else: raise ValueError("unsupported data layout:" + data_layout) param_shape = [channel_num] # create parameter scale = helper.create_parameter( attr=helper.param_attr, shape=param_shape, dtype=dtype, default_initializer=Constant(1.0)) bias = helper.create_parameter( attr=helper.bias_attr, shape=param_shape, dtype=dtype, is_bias=True) mean = helper.create_global_variable( dtype=input.dtype, shape=param_shape, persistable=True, stop_gradient=True) helper.set_variable_initializer(var=mean, initializer=Constant(0.0)) variance = helper.create_global_variable( dtype=input.dtype, shape=param_shape, persistable=True, stop_gradient=True) helper.set_variable_initializer(var=variance, initializer=Constant(1.0)) # create output # mean and mean_out share the same memory mean_out = mean # variance and variance out share the same memory variance_out = variance saved_mean = helper.create_tmp_variable(dtype=dtype, stop_gradient=True) saved_variance = helper.create_tmp_variable(dtype=dtype, stop_gradient=True) batch_norm_out = helper.create_tmp_variable(dtype) helper.append_op( type="batch_norm", inputs={ "X": input, "Scale": scale, "Bias": bias, "Mean": mean, "Variance": variance }, outputs={ "Y": batch_norm_out, "MeanOut": mean_out, "VarianceOut": variance_out, "SavedMean": saved_mean, "SavedVariance": saved_variance }, attrs={"momentum": momentum, "epsilon": epsilon, "is_test": is_test}) return helper.append_activation(batch_norm_out) def beam_search_decode(ids, scores, name=None): helper = LayerHelper('beam_search_decode', **locals()) sentence_ids = helper.create_tmp_variable(dtype=ids.dtype) sentence_scores = helper.create_tmp_variable(dtype=ids.dtype) helper.append_op( type="beam_search_decode", inputs={"Ids": ids, "Scores": scores}, outputs={ "SentenceIds": sentence_ids, "SentenceScores": sentence_scores }) return sentence_ids, sentence_scores def conv2d_transpose(input, num_filters, output_size=None, filter_size=None, padding=None, stride=None, dilation=None, param_attr=None, use_cudnn=True, name=None): """ **Convlution2D transpose layer** The convolution2D transpose layer calculates the output based on the input, filter, and dilations, strides, paddings. Input(Input) and output(Output) are in NCHW format. Where N is batch size, C is the number of channels, H is the height of the feature, and W is the width of the feature. Parameters(dilations, strides, paddings) are two elements. These two elements represent height and width, respectively. The details of convolution transpose layer, please refer to the following explanation and references `therein `_. For each input :math:`X`, the equation is: .. math:: Out = W \\ast X In the above equation: * :math:`X`: Input value, a tensor with NCHW format. * :math:`W`: Filter value, a tensor with MCHW format. * :math:`\\ast` : Convolution transpose operation. * :math:`Out`: Output value, the shape of :math:`Out` and :math:`X` may be different. Example: - Input: Input shape: $(N, C_{in}, H_{in}, W_{in})$ Filter shape: $(C_{in}, C_{out}, H_f, W_f)$ - Output: Output shape: $(N, C_{out}, H_{out}, W_{out})$ Where .. math:: H_{out} &= (H_{in} - 1) * strides[0] - 2 * paddings[0] + dilations[0] * (H_f - 1) + 1 \\\\ W_{out} &= (W_{in} - 1) * strides[1] - 2 * paddings[1] + dilations[1] * (W_f - 1) + 1 Args: input(Variable): The input image with [N, C, H, W] format. num_filters(int): The number of the filter. It is as same as the output image channel. output_size(int|tuple|None): The output image size. If output size is a tuple, it must contain two integers, (image_H, image_W). This parameter only works when filter_size is None. filter_size(int|tuple|None): The filter size. If filter_size is a tuple, it must contain two integers, (filter_size_H, filter_size_W). Otherwise, the filter will be a square. None if use output size to calculate filter_size. padding(int|tuple): The padding size. If padding is a tuple, it must contain two integers, (padding_H, padding_W). Otherwise, the padding_H = padding_W = padding. Default: padding = 0. stride(int|tuple): The stride size. If stride is a tuple, it must contain two integers, (stride_H, stride_W). Otherwise, the stride_H = stride_W = stride. Default: stride = 1. dilation(int|tuple): The dilation size. If dilation is a tuple, it must contain two integers, (dilation_H, dilation_W). Otherwise, the dilation_H = dilation_W = dilation. Default: dilation = 1. param_attr(ParamAttr): The parameters to the Conv2d_transpose Layer. Default: None use_cudnn(bool): Use cudnn kernel or not, it is valid only when the cudnn library is installed. Default: True name(str|None): A name for this layer(optional). If set None, the layer will be named automatically. Returns: Variable: The tensor variable storing the convolution transpose result. Raises: ValueError: If the shapes of input, filter_size, stride, padding and groups mismatch. Examples: .. code-block:: python data = fluid.layers.data(name='data', shape=[3, 32, 32], dtype='float32') conv2d_transpose = fluid.layers.conv2d_transpose(input=data, num_filters=2, filter_size=3) """ helper = LayerHelper("conv2d_transpose", **locals()) if not isinstance(input, Variable): raise TypeError("Input of conv2d_transpose must be Variable") input_channel = input.shape[1] op_attr = dict() if isinstance(padding, int): op_attr['paddings'] = [padding, padding] elif padding is not None: op_attr['paddings'] = padding if isinstance(stride, int): op_attr['strides'] = [stride, stride] elif stride is not None: op_attr['strides'] = stride if isinstance(dilation, int): op_attr['dilations'] = [dilation, dilation] elif dilation is not None: op_attr['dilations'] = dilation if not isinstance(use_cudnn, bool): raise ValueError("use_cudnn should be True or False") op_attr['use_cudnn'] = use_cudnn if filter_size is None: if output_size is None: raise ValueError("output_size must be set when filter_size is None") if isinstance(output_size, int): output_size = [output_size, output_size] padding = op_attr.get('paddings', [0, 0]) stride = op_attr.get('strides', [1, 1]) dilation = op_attr.get('dilations', [1, 1]) h_in = input.shape[2] w_in = input.shape[3] filter_size_h = (output_size[0] - (h_in - 1) * stride[0] + 2 * padding[0] - 1) / dilation[0] + 1 filter_size_w = (output_size[1] - (w_in - 1) * stride[1] + 2 * padding[1] - 1) / dilation[1] + 1 filter_size = [filter_size_h, filter_size_w] elif isinstance(filter_size, int): filter_size = [filter_size, filter_size] filter_shape = [input_channel, num_filters] + filter_size img_filter = helper.create_parameter( dtype=input.dtype, shape=filter_shape, attr=helper.param_attr) out = helper.create_tmp_variable(dtype=input.dtype) helper.append_op( type='conv2d_transpose', inputs={'Input': [input], 'Filter': [img_filter]}, outputs={'Output': out}, attrs=op_attr) return out def sequence_expand(x, y, name=None): """Sequence Expand Layer. This layer will expand the input variable **x** according to LoD information of **y**. And the following examples will explain how sequence_expand works: .. code-block:: text * Case 1 x is a LoDTensor: x.lod = [[0, 2, 3], [0, 1, 3, 4]] x.data = [a, b, c, d] x.dims = [4, 1] y is a LoDTensor: y.lod = [[0, 2, 4], [0, 3, 6, 7, 8]] with condition len(y.lod[-1]) - 1 == x.dims[0] then output is a 2-level LoDTensor: out.lod = [[0, 2, 4], [0, 3, 6, 7, 8]] out.data = [a, a, a, b, b, b, c, d] out.dims = [8, 1] * Case 2 x is a Tensor: x.data = [a, b, c] x.dims = [3, 1] y is a LoDTensor: y.lod = [[0, 2, 3, 6]] with condition len(y.lod[-1]) - 1 == x.dims[0] then output is a 1-level LoDTensor: out.lod = [[0, 2, 3, 6]] out.data = [a, a, b, c, c, c] out.dims = [6, 1] Args: x (Variable): The input variable which is a Tensor or LoDTensor. y (Variable): The input variable which is a LoDTensor. name(str|None): A name for this layer(optional). If set None, the layer will be named automatically. Returns: Variable: The expanded variable which is a LoDTensor. Examples: .. code-block:: python x = fluid.layers.data(name='x', shape=[10], dtype='float32') y = fluid.layers.data(name='y', shape=[10, 20], dtype='float32', lod_level=1) out = layers.sequence_expand(x=x, y=y) """ helper = LayerHelper('sequence_expand', input=x, **locals()) dtype = helper.input_dtype() tmp = helper.create_tmp_variable(dtype) helper.append_op( type='sequence_expand', inputs={'X': x, 'Y': y}, outputs={'Out': tmp}) return tmp def lstm_unit(x_t, hidden_t_prev, cell_t_prev, forget_bias=0.0, param_attr=None, bias_attr=None, name=None): """Lstm unit layer. The equation of a lstm step is: .. math:: i_t & = \sigma(W_{x_i}x_{t} + W_{h_i}h_{t-1} + b_i) f_t & = \sigma(W_{x_f}x_{t} + W_{h_f}h_{t-1} + b_f) c_t & = f_tc_{t-1} + i_t tanh (W_{x_c}x_t + W_{h_c}h_{t-1} + b_c) o_t & = \sigma(W_{x_o}x_{t} + W_{h_o}h_{t-1} + b_o) h_t & = o_t tanh(c_t) The inputs of lstm unit include :math:`x_t`, :math:`h_{t-1}` and :math:`c_{t-1}`. The 2nd dimensions of :math:`h_{t-1}` and :math:`c_{t-1}` should be same. The implementation separates the linear transformation and non-linear transformation apart. Here, we take :math:`i_t` as an example. The linear transformation is applied by calling a `fc` layer and the equation is: .. math:: L_{i_t} = W_{x_i}x_{t} + W_{h_i}h_{t-1} + b_i The non-linear transformation is applied by calling `lstm_unit_op` and the equation is: .. math:: i_t = \sigma(L_{i_t}) This layer has two outputs including :math:`h_t` and :math:`o_t`. Args: x_t (Variable): The input value of current step, a 2-D tensor with shape M x N, M for batch size and N for input size. hidden_t_prev (Variable): The hidden value of lstm unit, a 2-D tensor with shape M x S, M for batch size and S for size of lstm unit. cell_t_prev (Variable): The cell value of lstm unit, a 2-D tensor with shape M x S, M for batch size and S for size of lstm unit. forget_bias (float): The forget bias of lstm unit. param_attr (ParamAttr): The attributes of parameter weights, used to set initializer, name etc. bias_attr (ParamAttr): The attributes of bias weights, if not False, bias weights will be created and be set to default value. name(str|None): A name for this layer(optional). If set None, the layer will be named automatically. Returns: tuple: The hidden value and cell value of lstm unit. Raises: ValueError: The ranks of **x_t**, **hidden_t_prev** and **cell_t_prev**\ not be 2 or the 1st dimensions of **x_t**, **hidden_t_prev** \ and **cell_t_prev** not be the same or the 2nd dimensions of \ **hidden_t_prev** and **cell_t_prev** not be the same. Examples: .. code-block:: python x_t = fluid.layers.fc(input=x_t_data, size=10) prev_hidden = fluid.layers.fc(input=prev_hidden_data, size=30) prev_cell = fluid.layers.fc(input=prev_cell_data, size=30) hidden_value, cell_value = fluid.layers.lstm_unit(x_t=x_t, hidden_t_prev=prev_hidden, cell_t_prev=prev_cell) """ helper = LayerHelper('lstm_unit', **locals()) if len(x_t.shape) != 2: raise ValueError("Rank of x_t must be 2.") if len(hidden_t_prev.shape) != 2: raise ValueError("Rank of hidden_t_prev must be 2.") if len(cell_t_prev.shape) != 2: raise ValueError("Rank of cell_t_prev must be 2.") if x_t.shape[0] != hidden_t_prev.shape[0] or x_t.shape[ 0] != cell_t_prev.shape[0]: raise ValueError("The 1st dimensions of x_t, hidden_t_prev and " "cell_t_prev must be the same.") if hidden_t_prev.shape[1] != cell_t_prev.shape[1]: raise ValueError("The 2nd dimensions of hidden_t_prev and " "cell_t_prev must be the same.") if bias_attr is None: bias_attr = ParamAttr() size = cell_t_prev.shape[1] concat_out = concat(input=[x_t, hidden_t_prev], axis=1) fc_out = fc(input=concat_out, size=4 * size, param_attr=param_attr, bias_attr=bias_attr) dtype = x_t.dtype c = helper.create_tmp_variable(dtype) h = helper.create_tmp_variable(dtype) helper.append_op( type='lstm_unit', inputs={"X": fc_out, "C_prev": cell_t_prev}, outputs={"C": c, "H": h}, attrs={"forget_bias": forget_bias}) return h, c def reduce_sum(input, dim=None, keep_dim=False, name=None): """ Computes the sum of tensor elements over the given dimension. Args: input (Variable): The input variable which is a Tensor or LoDTensor. dim (int|None): The dimension along which the sum is performed. If :attr:`None`, sum all elements of :attr:`input` and return a Tensor variable with a single element, otherwise must be in the range :math:`[-rank(input), rank(input))`. If :math:`dim < 0`, the dimension to reduce is :math:`rank + dim`. keep_dim (bool): Whether to reserve the reduced dimension in the output Tensor. The result tensor will have one fewer dimension than the :attr:`input` unless :attr:`keep_dim` is true. name(str|None): A name for this layer(optional). If set None, the layer will be named automatically. Returns: Variable: The reduced Tensor variable. Examples: .. code-block:: python # x is a Tensor variable with following elements: # [[0.2, 0.3, 0.5, 0.9] # [0.1, 0.2, 0.6, 0.7]] # Each example is followed by the correspending output tensor. fluid.layers.reduce_sum(x) # [3.5] fluid.layers.reduce_sum(x, dim=0) # [0.3, 0.5, 1.1, 1.6] fluid.layers.reduce_sum(x, dim=-1) # [1.9, 1.6] fluid.layers.reduce_sum(x, dim=1, keep_dim=True) # [[1.9], [1.6]] """ helper = LayerHelper('reduce_sum', **locals()) out = helper.create_tmp_variable(dtype=helper.input_dtype()) helper.append_op( type='reduce_sum', inputs={'X': input}, outputs={'Out': out}, attrs={ 'dim': dim if dim != None else 0, 'keep_dim': keep_dim, 'reduce_all': True if dim == None else False }) return out def reduce_mean(input, dim=None, keep_dim=False, name=None): """ Computes the mean of tensor elements over the given dimension. Args: input (Variable): The input variable which is a Tensor or LoDTensor. dim (int|None): The dimension along which the mean is computed. If :attr:`None`, compute the mean over all elements of :attr:`input` and return a Tensor variable with a single element, otherwise must be in the range :math:`[-rank(input), rank(input))`. If :math:`dim < 0`, the dimension to reduce is :math:`rank + dim`. keep_dim (bool): Whether to reserve the reduced dimension in the output Tensor. The result tensor will have one fewer dimension than the :attr:`input` unless :attr:`keep_dim` is true. name(str|None): A name for this layer(optional). If set None, the layer will be named automatically. Returns: Variable: The reduced Tensor variable. Examples: .. code-block:: python # x is a Tensor variable with following elements: # [[0.2, 0.3, 0.5, 0.9] # [0.1, 0.2, 0.6, 0.7]] # Each example is followed by the correspending output tensor. fluid.layers.reduce_mean(x) # [0.4375] fluid.layers.reduce_mean(x, dim=0) # [0.15, 0.25, 0.55, 0.8] fluid.layers.reduce_mean(x, dim=-1) # [0.475, 0.4] fluid.layers.reduce_mean(x, dim=1, keep_dim=True) # [[0.475], [0.4]] """ helper = LayerHelper('reduce_mean', **locals()) out = helper.create_tmp_variable(dtype=helper.input_dtype()) helper.append_op( type='reduce_mean', inputs={'X': input}, outputs={'Out': out}, attrs={ 'dim': dim if dim != None else 0, 'keep_dim': keep_dim, 'reduce_all': True if dim == None else False }) return out def reduce_max(input, dim=None, keep_dim=False, name=None): """ Computes the maximum of tensor elements over the given dimension. Args: input (Variable): The input variable which is a Tensor or LoDTensor. dim (int|None): The dimension along which the maximum is computed. If :attr:`None`, compute the maximum over all elements of :attr:`input` and return a Tensor variable with a single element, otherwise must be in the range :math:`[-rank(input), rank(input))`. If :math:`dim < 0`, the dimension to reduce is :math:`rank + dim`. keep_dim (bool): Whether to reserve the reduced dimension in the output Tensor. The result tensor will have one fewer dimension than the :attr:`input` unless :attr:`keep_dim` is true. name(str|None): A name for this layer(optional). If set None, the layer will be named automatically. Returns: Variable: The reduced Tensor variable. Examples: .. code-block:: python # x is a Tensor variable with following elements: # [[0.2, 0.3, 0.5, 0.9] # [0.1, 0.2, 0.6, 0.7]] # Each example is followed by the correspending output tensor. fluid.layers.reduce_max(x) # [0.9] fluid.layers.reduce_max(x, dim=0) # [0.2, 0.3, 0.6, 0.9] fluid.layers.reduce_max(x, dim=-1) # [0.9, 0.7] fluid.layers.reduce_max(x, dim=1, keep_dim=True) # [[0.9], [0.7]] """ helper = LayerHelper('reduce_max', **locals()) out = helper.create_tmp_variable(dtype=helper.input_dtype()) helper.append_op( type='reduce_max', inputs={'X': input}, outputs={'Out': out}, attrs={ 'dim': dim if dim != None else 0, 'keep_dim': keep_dim, 'reduce_all': True if dim == None else False }) return out def reduce_min(input, dim=None, keep_dim=False, name=None): """ Computes the minimum of tensor elements over the given dimension. Args: input (Variable): The input variable which is a Tensor or LoDTensor. dim (int|None): The dimension along which the minimum is computed. If :attr:`None`, compute the minimum over all elements of :attr:`input` and return a Tensor variable with a single element, otherwise must be in the range :math:`[-rank(input), rank(input))`. If :math:`dim < 0`, the dimension to reduce is :math:`rank + dim`. keep_dim (bool): Whether to reserve the reduced dimension in the output Tensor. The result tensor will have one fewer dimension than the :attr:`input` unless :attr:`keep_dim` is true. name(str|None): A name for this layer(optional). If set None, the layer will be named automatically. Returns: Variable: The reduced Tensor variable. Examples: .. code-block:: python # x is a Tensor variable with following elements: # [[0.2, 0.3, 0.5, 0.9] # [0.1, 0.2, 0.6, 0.7]] # Each example is followed by the correspending output tensor. fluid.layers.reduce_min(x) # [0.1] fluid.layers.reduce_min(x, dim=0) # [0.1, 0.2, 0.5, 0.7] fluid.layers.reduce_min(x, dim=-1) # [0.2, 0.1] fluid.layers.reduce_min(x, dim=1, keep_dim=True) # [[0.2], [0.1]] """ helper = LayerHelper('reduce_min', **locals()) out = helper.create_tmp_variable(dtype=helper.input_dtype()) helper.append_op( type='reduce_min', inputs={'X': input}, outputs={'Out': out}, attrs={ 'dim': dim if dim != None else 0, 'keep_dim': keep_dim, 'reduce_all': True if dim == None else False }) return out def split(input, num_or_sections, dim=-1, name=None): """ Split the input tensor into multiple sub-tensors. Args: input (Variable): The input variable which is a Tensor or LoDTensor. num_or_sections (int|list): If :attr:`num_or_sections` is an integer, then the integer indicates the number of equal sized sub-tensors that the tensor will be divided into. If :attr:`num_or_sections` is a list of integers, the length of list indicates the number of sub-tensors and the integers indicate the sizes of sub-tensors' :attr:`dim` dimension orderly. dim (int): The dimension along which to split. If :math:`dim < 0`, the dimension to split along is :math:`rank(input) + dim`. name(str|None): A name for this layer(optional). If set None, the layer will be named automatically. Returns: List: The list of segmented tensor variables. Examples: .. code-block:: python # x is a Tensor variable with shape [3, 9, 5]: x0, x1, x2 = fluid.layers.split(x, num_or_sections=3, dim=1) x0.shape # [3, 3, 5] x1.shape # [3, 3, 5] x2.shape # [3, 3, 5] x0, x1, x2 = fluid.layers.split(x, num_or_sections=[2, 3, 4], dim=1) x0.shape # [3, 2, 5] x1.shape # [3, 3, 5] x2.shape # [3, 4, 5] """ helper = LayerHelper('split', **locals()) input_shape = input.shape dim = (len(input_shape) + dim) if dim < 0 else dim if isinstance(num_or_sections, int): assert num_or_sections > 1, 'num_or_sections must be more than 1.' num = num_or_sections else: assert len(num_or_sections) < input_shape[ dim], 'len(num_or_sections) must not be more than input.shape[dim].' num = len(num_or_sections) outs = [ helper.create_tmp_variable(dtype=helper.input_dtype()) for i in range(num) ] helper.append_op( type='split', inputs={'X': input}, outputs={'Out': outs}, attrs={ 'num': num_or_sections if isinstance(num_or_sections, int) else 0, 'sections': num_or_sections if isinstance(num_or_sections, list) else [], 'axis': dim }) return outs def l2_normalize(x, axis, epsilon=1e-12, name=None): """ **L2 normalize Layer** The l2 normalize layer normalizes `x` along dimension `axis` using an L2 norm. For a 1-D tensor (`dim` is fixed to 0), this layer computes output = x / sqrt(max(sum(x**2), epsilon)) For `x` with more dimensions, this layer independently normalizes each 1-D slice along dimension `axis`. Args: x(Variable|list): The input tensor to l2_normalize layer. axis(int): Dimension along which to normalize the input. epsilon(float): A lower bound value for `x`'s l2 norm. sqrt(epsilon) will be used as the divisor if the l2 norm of `x` is less than sqrt(epsilon). name(str|None): A name for this layer(optional). If set None, the layer will be named automatically. Returns: Variable: The output tensor variable. Examples: .. code-block:: python data = fluid.layers.data(name="data", shape=(3, 17, 13), dtype="float32") fc = fluid.layers.l2_normalize(x=data, axis=1) """ if len(x.shape) == 1: axis = 0 helper = LayerHelper("l2_normalize", **locals()) square = helper.create_tmp_variable(dtype=x.dtype) helper.append_op(type="square", inputs={"X": x}, outputs={"Out": square}) reduced_sum = helper.create_tmp_variable(dtype=x.dtype) helper.append_op( type="reduce_sum", inputs={"X": square}, outputs={"Out": reduced_sum}, attrs={ "dim": 1 if axis is None else axis, "keep_dim": True, "reduce_all": False }) # TODO(caoying) A lower bound value epsilon for the norm is needed to # imporve the numeric stability of reciprocal. This requires a maximum_op. rsquare = helper.create_tmp_variable(dtype=x.dtype) helper.append_op( type="reciprocal", inputs={"X": reduced_sum}, outputs={"Out": rsquare}) # TODO(caoying) the current elementwise_mul operator does not support a # general broadcast rule which broadcasts input(Y) to have the same # dimension with Input(X) starting from a specified dimension. So this # exanpsion is requred. Once a general broadcast rule is spported, this # expanding canbe removed. rsquare_expanded = helper.create_tmp_variable(dtype=x.dtype) expand_times = [1] * len(x.shape) expand_times[axis] = int(x.shape[axis]) helper.append_op( type="expand", inputs={"X": rsquare}, outputs={"Out": rsquare_expanded}, attrs={"expand_times": expand_times}) out = helper.create_tmp_variable(dtype=x.dtype) helper.append_op( type="elementwise_mul", inputs={"X": x, "Y": rsquare_expanded}, outputs={"Out": out}) return out def matmul(x, y, transpose_x=False, transpose_y=False, name=None): """ Applies matrix multiplication to two tensors. Currently, the input tensors' rank can be any, but when the rank of anyone inputs is bigger than 3, this two inputs' rank should be equal. The actual behavior depends on the shapes of :math:`x`, :math:`y` and the flag values of :attr:`transpose_x`, :attr:`transpose_y`. Specifically: - If a transpose flag is specified, the last two dimensions of the tensor are transposed. If the tensor is rank-1 of shape :math:`[D]`, then for :math:`x` it is treated as :math:`[1, D]` in nontransposed form and as :math:`[D, 1]` in transposed form, whereas for :math:`y` it is the opposite: It is treated as :math:`[D, 1]` in nontransposed form and as :math:`[1, D]` in transposed form. - After transpose, the two tensors are 2-D or n-D and matrix multiplication performs in the following way. - If both are 2-D, they are multiplied like conventional matrices. - If either is n-D, it is treated as a stack of matrices residing in the last two dimensions and a batched matrix multiply supporting broadcast applies on the two tensors. Also note that if the raw tensor :math:`x` or :math:`y` is rank-1 and nontransposed, the prepended or appended dimension :math:`1` will be removed after matrix multiplication. Args: x (Variable): The input variable which is a Tensor or LoDTensor. y (Variable): The input variable which is a Tensor or LoDTensor. transpose_x (bool): Whether to transpose :math:`x` before multiplication. transpose_y (bool): Whether to transpose :math:`y` before multiplication. name(str|None): A name for this layer(optional). If set None, the layer will be named automatically. Returns: Variable: The product Tensor variable. Examples: .. code-block:: python # Examples to clarify shapes of the inputs and output # x: [B, ..., M, K], y: [B, ..., K, N] fluid.layers.matmul(x, y) # out: [B, ..., M, N] # x: [B, M, K], y: [B, K, N] fluid.layers.matmul(x, y) # out: [B, M, N] # x: [B, M, K], y: [K, N] fluid.layers.matmul(x, y) # out: [B, M, N] # x: [B, M, K], y: [K] fluid.layers.matmul(x, y) # out: [B, M] # x: [M, K], y: [K, N] fluid.layers.matmul(x, y) # out: [M, N] # x: [K], y: [K] fluid.layers.matmul(x, y) # out: [1] # x: [M], y: [N] fluid.layers.matmul(x, y, True, True) # out: [M, N] """ helper = LayerHelper('matmul', **locals()) assert max(len(x.shape), len(y.shape)) <= 3 or len(x.shape) == len( y. shape), 'Inputs\' rank should be equal or their rank should be less 4.' out = helper.create_tmp_variable(dtype=helper.input_dtype()) helper.append_op( type='matmul', inputs={'X': x, 'Y': y}, outputs={'Out': out}, attrs={'transpose_X': transpose_x, 'transpose_Y': transpose_y}) return out def edit_distance(input, label, normalized=False, ignored_tokens=None, name=None): """ EditDistance operator computes the edit distances between a batch of hypothesis strings and their references. Edit distance, also called Levenshtein distance, measures how dissimilar two strings are by counting the minimum number of operations to transform one string into anthor. Here the operations include insertion, deletion, and substitution. For example, given hypothesis string A = "kitten" and reference B = "sitting", the edit distance is 3 for A will be transformed into B at least after two substitutions and one insertion: "kitten" -> "sitten" -> "sittin" -> "sitting" Input(Hyps) is a LoDTensor consisting of all the hypothesis strings with the total number denoted by `batch_size`, and the separation is specified by the LoD information. And the `batch_size` reference strings are arranged in order in the same way in the LoDTensor Input(Refs). Output(Out) contains the `batch_size` results and each stands for the edit stance for a pair of strings respectively. If Attr(normalized) is true, the edit distance will be divided by the length of reference string. Args: input(Variable): The indices for hypothesis strings. label(Variable): The indices for reference strings. normalized(bool): Indicated whether to normalize the edit distance by the length of reference string. ignored_tokens(list of int): Tokens that should be removed before calculating edit distance. Returns: Variable: sequence-to-sequence edit distance in shape [batch_size, 1]. Examples: .. code-block:: python x = fluid.layers.data(name='x', shape=[8], dtype='float32') y = fluid.layers.data(name='y', shape=[7], dtype='float32') cost = fluid.layers.edit_distance(input=x,label=y) """ helper = LayerHelper("edit_distance", **locals()) # remove some tokens from input and labels if ignored_tokens is not None and len(ignored_tokens) > 0: erased_input = helper.create_tmp_variable(dtype="int64") erased_label = helper.create_tmp_variable(dtype="int64") helper.append_op( type="sequence_erase", inputs={"X": [input]}, outputs={"Out": [erased_input]}, attrs={"tokens": ignored_tokens}) input = erased_input helper.append_op( type="sequence_erase", inputs={"X": [label]}, outputs={"Out": [erase_label]}, attrs={"tokens": ignored_tokens}) label = erased_label # edit distance op edit_distance_out = helper.create_tmp_variable(dtype="int64") sequence_num = helper.create_tmp_variable(dtype="int64") helper.append_op( type="edit_distance", inputs={"Hyps": [input], "Refs": [label]}, outputs={"Out": [edit_distance_out], "SequenceNum": [sequence_num]}, attrs={"normalized": normalized}) return edit_distance_out, sequence_num def ctc_greedy_decoder(input, blank, name=None): """ This op is used to decode sequences by greedy policy by below steps: 1. Get the indexes of max value for each row in input. a.k.a. numpy.argmax(input, axis=0). 2. For each sequence in result of step1, merge repeated tokens between two blanks and delete all blanks. A simple example as below: .. code-block:: text Given: input.data = [[0.6, 0.1, 0.3, 0.1], [0.3, 0.2, 0.4, 0.1], [0.1, 0.5, 0.1, 0.3], [0.5, 0.1, 0.3, 0.1], [0.5, 0.1, 0.3, 0.1], [0.2, 0.2, 0.2, 0.4], [0.2, 0.2, 0.1, 0.5], [0.5, 0.1, 0.3, 0.1]] input.lod = [[0, 4, 8]] Then: output.data = [[2], [1], [3]] output.lod = [[0, 2, 3]] Args: input(Variable): (LoDTensor), the probabilities of variable-length sequences, which is a 2-D Tensor with LoD information. It's shape is [Lp, num_classes + 1], where Lp is the sum of all input sequences' length and num_classes is the true number of classes. (not including the blank label). blank(int): the blank label index of Connectionist Temporal Classification (CTC) loss, which is in thehalf-opened interval [0, num_classes + 1). Returns: Variable: CTC greedy decode result. Examples: .. code-block:: python x = fluid.layers.data(name='x', shape=[8], dtype='float32') cost = fluid.layers.ctc_greedy_decoder(input=x, blank=0) """ helper = LayerHelper("ctc_greedy_decoder", **locals()) # top 1 op topk_out = helper.create_tmp_variable(dtype=input.dtype) topk_indices = helper.create_tmp_variable(dtype="int64") helper.append_op( type="top_k", inputs={"X": [input]}, outputs={"Out": [topk_out], "Indices": [topk_indices]}, attrs={"k": 1}) # ctc align op ctc_out = helper.create_tmp_variable(dtype="int64") helper.append_op( type="ctc_align", inputs={"Input": [topk_indices]}, outputs={"Output": [ctc_out]}, attrs={"merge_repeated": True, "blank": blank}) return ctc_out def warpctc(input, label, blank=0, norm_by_times=False, **kwargs): """ An operator integrating the open source Warp-CTC library (https://github.com/baidu-research/warp-ctc) to compute Connectionist Temporal Classification (CTC) loss. It can be aliased as softmax with CTC, since a native softmax activation is interated to the Warp-CTC library, to to normlize values for each row of the input tensor. Args: input(Variable): (LodTensor, default: LoDTensor), the unscaled probabilities of variable-length sequences, which is a 2-D Tensor with LoD information. It's shape is [Lp, num_classes + 1], where Lp is the sum of all input sequences' length and num_classes is the true number of classes. (not including the blank label). label(Variable): (LodTensor, default: LoDTensor), the ground truth of variable-length sequence, which is a 2-D Tensor with LoD information. It is of the shape [Lg, 1], where Lg is th sum of all labels' length. blank: (int, default: 0), the blank label index of Connectionist Temporal Classification (CTC) loss, which is in the half-opened interval [0, num_classes + 1). norm_by_times: (bool, default: false), whether to normalize the gradients by the number of time-step, which is also the sequence's length. There is no need to normalize the gradients if warpctc layer was follewed by a mean_op. Returns: Variable: The Connectionist Temporal Classification (CTC) loss, which is a 2-D Tensor of the shape [batch_size, 1]. Examples: .. code-block:: python y = layers.data(name='y', shape=[11, 8], dtype='float32', lod_level=1) y_predict = layers.data(name='y_predict', shape=[11, 1], dtype='float32') cost = layers.warpctc(input=y_predict, label=y) """ helper = LayerHelper('warpctc', **kwargs) loss_out = helper.create_tmp_variable(dtype=input.dtype) grad_out = helper.create_tmp_variable(dtype=input.dtype) helper.append_op( type='warpctc', inputs={'Logits': [input], 'Label': [label]}, outputs={'WarpCTCGrad': [grad_out], 'Loss': [loss_out]}, attrs={'blank': blank, 'norm_by_times': norm_by_times}) return loss_out def sequence_reshape(input, new_dim): """ **Sequence Reshape Layer** This layer will rearrange the input sequences. The new dimension is set by user. Length of each sequence is computed according to original length, original dimension and new dimension. The following example will help to illustrate the function of this layer: .. code-block:: text x is a LoDTensor: x.lod = [[0, 2, 6]] x.data = [[1, 2], [3, 4], [5, 6], [7, 8], [9, 10], [11, 12]] x.dims = [6, 2] set new_dim = 4 then out is a LoDTensor: out.lod = [[0, 1, 3]] out.data = [[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12]] out.dims = [3, 4] Currently, only 1-level LoDTensor is supported and please make sure (original length * original dimension) can be divided by new dimension with no remainder for each sequence. Args: input (Variable): (LodTensor, default: LoDTensor), a 2-D LoDTensor with shape being [N, M] where M for dimension. new_dim (int): New dimension which the input LoDTensor is reshaped to. Returns: Variable: Reshaped LoDTensor according to new dimension. Examples: .. code-block:: python x = fluid.layers.data(name='x', shape=[5, 20], dtype='float32', lod_level=1) x_reshaped = layers.sequence_reshape(input=x, new_dim=10) """ helper = LayerHelper('sequence_reshape', **locals()) out = helper.create_tmp_variable(helper.input_dtype()) helper.append_op( type='sequence_reshape', inputs={'X': [input]}, outputs={'Out': [out]}, attrs={'new_dim': new_dim}) return out @autodoc() def nce(input, label, num_total_classes, sample_weight=None, param_attr=None, bias_attr=None, num_neg_samples=None): helper = LayerHelper('nce', **locals()) assert isinstance(input, Variable) dim = input.shape[1] assert isinstance(label, Variable) num_true_class = label.shape[1] w = helper.create_parameter( attr=helper.param_attr, shape=[num_total_classes, dim], is_bias=False, dtype=input.dtype) b = helper.create_parameter( attr=helper.bias_attr, shape=[num_total_classes, 1], is_bias=True, dtype=input.dtype) cost = helper.create_tmp_variable(dtype=input.dtype) sample_logits = helper.create_tmp_variable(dtype=input.dtype) sample_labels = helper.create_tmp_variable(dtype=label.dtype) if num_neg_samples is None: num_neg_samples = 10 else: num_neg_samples = int(num_neg_samples) attrs = { 'num_total_classes': int(num_total_classes), 'num_neg_samples': num_neg_samples } helper.append_op( type='nce', inputs={ 'Input': input, 'Label': label, 'Weight': w, 'Bias': b, 'SampleWeight': sample_weight if sample_weight is not None else [] }, outputs={ 'Cost': cost, 'SampleLogits': sample_logits, 'SampleLabels': sample_labels }, attrs=attrs) return cost / (num_neg_samples + 1) def transpose(x, perm, name=None): """ **transpose Layer** Permute the dimensions of `input` according to `perm`. The `i`-th dimension of the returned tensor will correspond to the perm[i]-th dimension of `input`. Args: input (Variable): (Tensor), A Tensor. perm (list): A permutation of the dimensions of `input`. Returns: Variable: A transposed Tensor. Examples: .. code-block:: python x = fluid.layers.data(name='x', shape=[5, 10, 15], dtype='float32') x_transposed = layers.transpose(x, perm=[1, 0, 2]) """ if len(perm) != len(x.shape): raise ValueError( "Input(perm) is the permutation of dimensions of Input(input). " "It's length shoud be equal to Input(input)'s rank.") helper = LayerHelper('transpose', **locals()) out = helper.create_tmp_variable(x.dtype) helper.append_op( type='transpose', inputs={'X': [x]}, outputs={'Out': [out]}, attrs={'axis': perm}) return out def im2sequence(input, filter_size=1, stride=1, padding=0, name=None): """ Extracts image patches from the input tensor to form a tensor of shape {input.batch_size * output_height * output_width, filter_size_H * filter_size_W * input.channels} which is similar with im2col. This op use filter / kernel to scan images and convert these images to sequences. After expanding, the number of time step are output_height * output_width for an image, in which output_height and output_width are calculated by below equation: .. math:: output\_size = 1 + \ (2 * padding + img\_size - block\_size + stride - 1) / stride And the dimension of each time step is block_y * block_x * input.channels. Args: input (Variable): The input should be a tensor in NCHW format. filter_size(int|tuple|None): The filter size. If filter_size is a tuple, it must contain two integers, (filter_size_H, filter_size_W). Otherwise, the filter will be a square. stride(int|tuple): The stride size. If stride is a tuple, it must contain two integers, (stride_H, stride_W). Otherwise, the stride_H = stride_W = stride. Default: stride = 1. padding(int|tuple): The padding size. If padding is a tuple, it can contain two integers like (padding_H, padding_W) which means padding_up = padding_down = padding_H and padding_left = padding_right = padding_W. Or it can use (padding_up, padding_left, padding_down, padding_right) to indicate paddings of four direction. Otherwise, a scalar padding means padding_up = padding_down = padding_left = padding_right = padding Default: padding = 0. name (int): The name of this layer. It is optional. Returns: output: The output is a LoDTensor with shape {input.batch_size * output_height * output_width, filter_size_H * filter_size_W * input.channels}. If we regard output as a matrix, each row of this matrix is a step of a sequence. Examples: As an example: .. code-block:: text Given: x = [[[[ 6. 2. 1.] [ 8. 3. 5.] [ 0. 2. 6.]] [[ 2. 4. 4.] [ 6. 3. 0.] [ 6. 4. 7.]]] [[[ 6. 7. 1.] [ 5. 7. 9.] [ 2. 4. 8.]] [[ 1. 2. 1.] [ 1. 3. 5.] [ 9. 0. 8.]]]] x.dims = {2, 2, 3, 3} And: filter = [2, 2] stride = [1, 1] padding = [0, 0] Then: output.data = [[ 6. 2. 8. 3. 2. 4. 6. 3.] [ 2. 1. 3. 5. 4. 4. 3. 0.] [ 8. 3. 0. 2. 6. 3. 6. 4.] [ 3. 5. 2. 6. 3. 0. 4. 7.] [ 6. 7. 5. 7. 1. 2. 1. 3.] [ 7. 1. 7. 9. 2. 1. 3. 5.] [ 5. 7. 2. 4. 1. 3. 9. 0.] [ 7. 9. 4. 8. 3. 5. 0. 8.]] output.dims = {8, 9} output.lod = [[0, 4, 8]] The simple usage is: .. code-block:: python output = fluid.layers.im2sequence(input=layer, stride=[1, 1], filter_size=[2, 2]) """ if isinstance(filter_size, int): filter_size = [filter_size, filter_size] if isinstance(stride, int): stride = [stride, stride] if isinstance(padding, int): padding = [padding, padding] if len(padding) == 2: padding.append(padding[0]) padding.append(padding[1]) helper = LayerHelper('im2sequence', **locals()) out = helper.create_tmp_variable(dtype=helper.input_dtype()) helper.append_op( type='im2sequence', inputs={'X': input}, outputs={'Out': out}, attrs={ 'kernels': filter_size, 'strides': stride, 'paddings': padding, }) return out