Add padding support for crf_decoding (#19057)

* Add padding support for crf_decoding

* Fixes in comupte kernel

test=develop

* Update API Spec

test=develop

* Update API.spec

test=develop

* Avoid using paddle_enforce

test=develop

* Fix enforce

test=develop

paddle/fluid/API.spec

@@ -116,7 +116,7 @@ paddle.fluid.layers.dynamic_lstmp (ArgSpec(args=['input', 'size', 'proj_size', '
 paddle.fluid.layers.dynamic_gru (ArgSpec(args=['input', 'size', 'param_attr', 'bias_attr', 'is_reverse', 'gate_activation', 'candidate_activation', 'h_0', 'origin_mode'], varargs=None, keywords=None, defaults=(None, None, False, 'sigmoid', 'tanh', None, False)), ('document', '83617c165827e030636c80486d5de6f3'))
 paddle.fluid.layers.gru_unit (ArgSpec(args=['input', 'hidden', 'size', 'param_attr', 'bias_attr', 'activation', 'gate_activation', 'origin_mode'], varargs=None, keywords=None, defaults=(None, None, 'tanh', 'sigmoid', False)), ('document', '33974b9bfa69f2f1eb85e6f956dff04e'))
 paddle.fluid.layers.linear_chain_crf (ArgSpec(args=['input', 'label', 'param_attr'], varargs=None, keywords=None, defaults=(None,)), ('document', '34f96be41684b0959897a9e735997e20'))
-paddle.fluid.layers.crf_decoding (ArgSpec(args=['input', 'param_attr', 'label'], varargs=None, keywords=None, defaults=(None,)), ('document', 'c469f22029f7b5d41ecd44dfa1e81ffd'))
+paddle.fluid.layers.crf_decoding (ArgSpec(args=['input', 'param_attr', 'label'], varargs=None, keywords=None, defaults=(None,)), ('document', '5ce117258e243be1c81539e254178d90'))
 paddle.fluid.layers.cos_sim (ArgSpec(args=['X', 'Y'], varargs=None, keywords=None, defaults=None), ('document', '8e6ce424cf9e261ef32ee229c06a6e66'))
 paddle.fluid.layers.cross_entropy (ArgSpec(args=['input', 'label', 'soft_label', 'ignore_index'], varargs=None, keywords=None, defaults=(False, -100)), ('document', 'f43c659ca1749a3f0ff2231e6dfda07d'))
 paddle.fluid.layers.bpr_loss (ArgSpec(args=['input', 'label', 'name'], varargs=None, keywords=None, defaults=(None,)), ('document', '6263dfdeb6c670fa0922c9cbc8fb1bf4'))

paddle/fluid/operators/crf_decoding_op.cc

@@ -19,14 +19,17 @@ namespace operators {
 class CRFDecodingOpMaker : public framework::OpProtoAndCheckerMaker {
  public:
   void Make() override {
-    AddInput("Emission",
-             "(LoDTensor, default: LoDTensor<float>). A LoDTensor with shape "
-             "[N x D] where N is the size of the mini-batch and D is the total "
-             "tag number. This input is the unscaled emission weight matrix of "
-             "the linear_chain_crf operator.");
+    AddInput(
+        "Emission",
+        "(Tensor<float>/LoDTensor<float>). For a LoDTensor input, its "
+        "shape is [N x D] where N is the total sequence length of the "
+        "mini-batch and D is the total tag number. While for a tensor "
+        "input, its shape is [B X S X D] with B the batch size and S the "
+        "sequence length of each sample after padding. This input is the "
+        "unscaled emission weight matrix of the linear_chain_crf operator.");
     AddInput(
         "Transition",
-        "(Tensor, default: Tensor<float>). A Tensor with shape [(D + 2) x D]. "
+        "(Tensor<float>). A Tensor with shape [(D + 2) x D]. "
         "This input is the transition weights learned by the linear_chain_crf "
         "operator, denoted as w. The 1st row of w are transition weights for "
         "the start mask. The 2nd row of w are transition weights for the end "
@@ -34,15 +37,24 @@ class CRFDecodingOpMaker : public framework::OpProtoAndCheckerMaker {
         "w. See more details in comments of the linear_chain_crf operator.");
     AddInput(
         "Label",
-        "(LoDTensor,  LoDTensor<int64_t>). The ground truth with shape "
-        "[N x 1]. This input is optional. See more details in the operator's "
-        "comments.")
+        "(Tensor<int64_t>/LoDTensor<int64_t>). The ground truth with shape "
+        "[N x 1] (for LoDTensor) or [B x S] (for Tensor). This input is "
+        "optional. "
+        "See more details in the operator's comments.")
         .AsDispensable();
     AddOutput(
         "ViterbiPath",
-        "(LoDTensor, LoDTensor<int64_t>). The decoding results. What to "
+        "(Tensor<int64_t>/LoDTensor<int64_t>). The decoding results. What to "
         "return changes depending on whether the Input(Label) (the ground "
         "truth) is given. See more details in the operator's comment.");
+    AddInput("Length",
+             "(Tensor<int64_t>). The actual length of each sample before "
+             "padding with shape [B x 1]. It means the Input(Emission), "
+             "Input(Label) "
+             "and Output(ViterbiPath) are common tensors with padding when "
+             "this input "
+             "is given.")
+        .AsDispensable();
     AddComment(R"DOC(
 The crf_decoding operator reads the emission feature weights and the transition
 feature weights learned by the linear_chain_crf operator. It implements the
@@ -55,15 +67,16 @@ The output of this operator changes according to whether Input(Label) is given:
 1. Input(Label) is given:
    This happens in training. This operator is used to co-work with the chunk_eval
    operator.
-   When Input(Label) is given, the crf_decoding operator returns a row vector
-   with shape [N x 1] whose values are fixed to be 0, indicating an incorrect
-   prediction, or 1 indicating a tag is correctly predicted. Such an output is the
-   input to chunk_eval operator.
+   When Input(Label) is given, the crf_decoding operator returns tensor with the 
+   sampe shape as Input(Label) whose values are fixed to be 0, indicating an 
+   incorrect prediction, or 1 indicating a tag is correctly predicted. Such an 
+   output is the input to chunk_eval operator.
 
 2. Input(Label) is not given:
    This is the standard decoding process.
 
-The crf_decoding operator returns a row vector with shape [N x 1] whose values
+The crf_decoding operator returns a row vector with shape [N x 1]/[B x S], here 
+the shape depends on the inputs are LoDTensors or common tensors, whose values
 range from 0 to maximum tag number - 1, Each element indicates an index of a
 predicted tag.
 )DOC");
@@ -75,37 +88,46 @@ class CRFDecodingOp : public framework::OperatorWithKernel {
   using framework::OperatorWithKernel::OperatorWithKernel;
 
   void InferShape(framework::InferShapeContext* ctx) const override {
-    PADDLE_ENFORCE(ctx->HasInput("Emission"),
+    PADDLE_ENFORCE_EQ(ctx->HasInput("Emission"), true,
                       "Input(Emission) should be not null.");
-    PADDLE_ENFORCE(ctx->HasInput("Transition"),
+    PADDLE_ENFORCE_EQ(ctx->HasInput("Transition"), true,
                       "Input(Transition) should be not null.");
 
-    PADDLE_ENFORCE(ctx->HasOutput("ViterbiPath"),
+    PADDLE_ENFORCE_EQ(ctx->HasOutput("ViterbiPath"), true,
                       "Output(ViterbiPath) should be not null.");
 
     auto emission_dims = ctx->GetInputDim("Emission");
+    bool has_length = ctx->HasInput("Length");
+
+    if (has_length) {
+      PADDLE_ENFORCE_EQ(emission_dims.size(), 3,
+                        "The Input(Emission) should be a 3-D tensor.");
+    } else {
       PADDLE_ENFORCE_EQ(emission_dims.size(), 2,
                         "The Input(Emission) should be a 2-D tensor.");
-    PADDLE_ENFORCE(emission_dims[0], "An empty mini-batch is not allowed.");
+    }
+    PADDLE_ENFORCE_NE(emission_dims[0], 0,
+                      "An empty mini-batch is not allowed.");
 
     auto transition_dims = ctx->GetInputDim("Transition");
-    PADDLE_ENFORCE_EQ(transition_dims.size(), 2,
+    PADDLE_ENFORCE_EQ(transition_dims.size(), 2UL,
                       "The Input(Transition) should be a 2-D tensor.");
     PADDLE_ENFORCE_EQ(
         transition_dims[0] - 2, transition_dims[1],
         "An invalid dimension for the Input(Transition), which should "
         "be a 2-D tensor with shape [(D + 2) x D].");
-    if (ctx->IsRuntime() || (emission_dims[1] > 0 && transition_dims[1] > 0)) {
+    if (ctx->IsRuntime() || (emission_dims[emission_dims.size() - 1] > 0 &&
+                             transition_dims[transition_dims.size() - 1] > 0)) {
       PADDLE_ENFORCE_EQ(
-          emission_dims[1], transition_dims[1],
-          "The 2nd dimension of the Input(Emission) and the Input(Transition) "
+          emission_dims[emission_dims.size() - 1],
+          transition_dims[transition_dims.size() - 1],
+          "The last dimension of the Input(Emission) and the Input(Transition) "
           "should be equal to the tag number.");
     }
     if (ctx->HasInput("Label")) {
       auto label_dims = ctx->GetInputDim("Label");
-      PADDLE_ENFORCE(label_dims.size() == 2UL && label_dims[1] == 1UL,
-                     "The Input(Label) should be a 2-D tensor with the 2nd "
-                     "dimensions fixed to 1.");
+      PADDLE_ENFORCE_EQ(label_dims.size(), 2UL,
+                        "The Input(Label) should be a 2-D tensor");
       if (ctx->IsRuntime() || (emission_dims[0] > 0 && label_dims[0] > 0)) {
         PADDLE_ENFORCE_EQ(
             emission_dims[0], label_dims[0],
@@ -115,8 +137,12 @@ class CRFDecodingOp : public framework::OperatorWithKernel {
     }
 
     ctx->ShareLoD("Emission", /*->*/ "ViterbiPath");
+    if (has_length) {
+      ctx->SetOutputDim("ViterbiPath", {emission_dims[0], emission_dims[1]});
+    } else {
       ctx->SetOutputDim("ViterbiPath", {emission_dims[0], 1});
     }
+  }
 
  protected:
   framework::OpKernelType GetExpectedKernelType(

paddle/fluid/operators/crf_decoding_op.h

@@ -35,16 +35,42 @@ class CRFDecodingOpKernel : public framework::OpKernel<T> {
     auto* label = ctx.Input<LoDTensor>("Label");
     auto* decoded_path = ctx.Output<Tensor>("ViterbiPath");
 
+    int64_t* path = decoded_path->mutable_data<int64_t>(platform::CPUPlace());
+    math::SetConstant<DeviceContext, int64_t>()(
+        ctx.template device_context<DeviceContext>(), decoded_path, 0);
+
+    bool has_length = ctx.HasInput("Length");
+    if (has_length) {
+      auto* length = ctx.Input<Tensor>("Length");
+      const size_t seq_num = length->numel();
+      const int64_t* length_data = length->data<int64_t>();
+      auto in_dims = emission_weights->dims();
+
+      auto& dev_ctx = ctx.template device_context<DeviceContext>();
+      framework::Tensor emission_weights_tmp =
+          ctx.AllocateTmpTensor<T, DeviceContext>(emission_weights->dims(),
+                                                  dev_ctx);
+      emission_weights_tmp.ShareDataWith(*emission_weights);
+      emission_weights_tmp.Resize({in_dims[0] * in_dims[1], in_dims[2]});
+
+      decoded_path->Resize({in_dims[0] * in_dims[1], 1});
+      for (size_t i = 0; i < seq_num; ++i) {
+        if (length_data[i] == 0) continue;
+        int start_pos = i * in_dims[1];
+        int end_pos = start_pos + static_cast<int>(length_data[i]);
+        Tensor decoded_path_one_seq = decoded_path->Slice(start_pos, end_pos);
+        Decode(emission_weights_tmp.Slice(start_pos, end_pos),
+               *transition_weights, &decoded_path_one_seq);
+      }
+      decoded_path->Resize({in_dims[0], in_dims[1]});
+    } else {
       PADDLE_ENFORCE_EQ(emission_weights->NumLevels(), 1UL,
                         "The Input(Emission) should be a sequence.");
       auto lod = emission_weights->lod();
-    PADDLE_ENFORCE(lod.size(), "Input(Emission) must be a sequence.");
+      PADDLE_ENFORCE_GT(lod.size(), 0, "Input(Emission) must be a sequence.");
       const size_t level = 0;
       const size_t seq_num = lod[level].size() - 1;
 
-    int64_t* path = decoded_path->mutable_data<int64_t>(platform::CPUPlace());
-    math::SetConstant<DeviceContext, int64_t>()(
-        ctx.template device_context<DeviceContext>(), decoded_path, 0);
       for (size_t i = 0; i < seq_num; ++i) {
         if (lod[level][i] == lod[level][i + 1]) continue;
         int start_pos = static_cast<int>(lod[level][i]);
@@ -53,13 +79,15 @@ class CRFDecodingOpKernel : public framework::OpKernel<T> {
         Decode(emission_weights->Slice(start_pos, end_pos), *transition_weights,
                &decoded_path_one_seq);
       }
-
+    }
     if (label) {
+      if (!has_length) {
         PADDLE_ENFORCE_EQ(label->NumLevels(), 1UL,
                           "The Input(Label) should be a sequence.");
+      }
       const int64_t* label_value = label->data<int64_t>();
-      size_t batch_size = emission_weights->dims()[0];
-      for (size_t i = 0; i < batch_size; ++i) {
+      size_t numel = label->numel();
+      for (size_t i = 0; i < numel; ++i) {
         path[i] = label_value[i] == path[i] ? 1 : 0;
       }
     }

python/paddle/fluid/tests/unittests/test_crf_decoding_op.py

@@ -176,5 +176,55 @@ class TestCRFDecodingOp4(TestCRFDecodingOp2):
         self.lod = [[0, 2, 3, 0]]
 
 
+class TestCRFDecodingOp5(OpTest):
+    """
+    Compare the dynamic program with random generated parameters and inputs
+    with grouth truth not being given.
+    """
+
+    def seq_pad(self, data, length):
+        max_len = np.max(length)
+        shape = [len(length), max_len] + list(data.shape[1:])
+        padded = np.zeros(shape).astype(data.dtype)
+        offset = 0
+        for i, l in enumerate(length):
+            padded[i, 0:l] = data[offset:offset + l]
+            offset += l
+        return np.squeeze(padded)
+
+    def set_test_data(self):
+        SEQ_NUM = 3
+        TAG_NUM = 17
+        MAX_SEQ_LEN = 10
+
+        lod = [[]]
+        total_len = 0
+        for i in range(SEQ_NUM):
+            lod[-1].append(random.randint(1, MAX_SEQ_LEN))
+            total_len += lod[-1][-1]
+        emission = np.random.uniform(-1, 1,
+                                     [total_len, TAG_NUM]).astype("float64")
+        transition = np.random.uniform(-0.5, 0.5,
+                                       [TAG_NUM + 2, TAG_NUM]).astype("float64")
+
+        self.inputs = {
+            "Emission": self.seq_pad(emission, lod[0]),
+            "Transition": transition,
+            "Length": np.array(lod).astype('int64'),
+        }
+
+        decoder = CRFDecoding(emission, transition, lod[0])
+        decoded_path = decoder.decode()
+
+        self.outputs = {"ViterbiPath": self.seq_pad(decoded_path, lod[0])}
+
+    def setUp(self):
+        self.op_type = "crf_decoding"
+        self.set_test_data()
+
+    def test_check_output(self):
+        self.check_output()
+
+
 if __name__ == "__main__":
     unittest.main()