Restructure the code of ltr

ltr/README.md

@@ -96,17 +96,15 @@ $$\lambda _{i,j}=\frac{\partial C}{\partial s_{i}} = \frac{1}{2}(1-S_{i,j})-\fra
 
 训练`RankNet`模型在命令行执行：
 ```bash
-python ranknet.py
+python train.py --model_type ranknet
 ```
 初次执行会自动下载数据，训练RankNet模型，并将每个轮次的模型参数存储下来。
 
 ### RankNet模型预测
 
 使用训练好的`RankNet`模型继续进行预测，在命令行执行：
 ```bash
-python ranknet.py \
-  --run_type infer \
-  --test_model_path models/ranknet_params_0.tar.gz
+python infer.py --model_type ranknet --test_model_path models/ranknet_params_0.tar.gz
 ```
 
 本例提供了rankNet模型的训练和预测两个部分。完成训练后的模型分为拓扑结构(需要注意`rank_cost`不是模型拓扑结构的一部分)和模型参数文件两部分。在本例子中复用了`ranknet`训练时的模型拓扑结构`half_ranknet`，模型参数从外存中加载。模型预测的输入为单个文档的特征向量，模型会给出相关性得分。将预测得分排序即可得到最终的文档相关性排序结果。
@@ -193,7 +191,7 @@ $$\lambda _{i,j}=\frac{\partial C}{\partial s_{i}}=-\frac{\sigma }{1+e^{\sigma (
 
 训练`LambdaRank`模型在命令行执行：
 ```bash
-python lambda_rank.py
+python train.py --model_type lambdarank
 ```
 初次运行脚本会自动下载数据训练LambdaRank模型，并将每个轮次的模型存储下来。
 
@@ -203,9 +201,7 @@ LambdaRank模型预测过程和RankNet相同。预测时的模型拓扑结构复
 
 使用训练好的`LambdaRank`模型继续进行预测，在命令行执行：
 ```bash
-python lambda_rank.py \
-  --run_type infer \
-  --test_model_path models/lambda_rank_params_0.tar.gz
+python infer.py --model_type lambdarank --test_model_path models/lambda_rank_params_0.tar.gz
 ```
 
 ## 自定义 LambdaRank数据

ltr/infer.py

@@ -0,0 +1,115 @@
+import os
+import gzip
+import functools
+import argparse
+
+import paddle.v2 as paddle
+
+from ranknet import half_ranknet
+from lambda_rank import lambda_rank
+
+
+def ranknet_infer(input_dim, model_path):
+    """
+    RankNet model inference interface.
+    """
+    # we just need half_ranknet to predict a rank score,
+    # which can be used in sort documents
+    output = half_ranknet("right", input_dim)
+    parameters = paddle.parameters.Parameters.from_tar(gzip.open(model_path))
+
+    # load data of same query and relevance documents,
+    # need ranknet to rank these candidates
+    infer_query_id = []
+    infer_data = []
+    infer_doc_index = []
+
+    # convert to mq2007 built-in data format
+    # <query_id> <relevance_score> <feature_vector>
+    plain_txt_test = functools.partial(
+        paddle.dataset.mq2007.test, format="plain_txt")
+
+    for query_id, relevance_score, feature_vector in plain_txt_test():
+        infer_query_id.append(query_id)
+        infer_data.append([feature_vector])
+
+    # predict score of infer_data document.
+    # Re-sort the document base on predict score
+    # in descending order. then we build the ranking documents
+    scores = paddle.infer(
+        output_layer=output, parameters=parameters, input=infer_data)
+    for query_id, score in zip(infer_query_id, scores):
+        print "query_id : ", query_id, " score : ", score
+
+
+def lambda_rank_infer(input_dim, model_path):
+    """
+    LambdaRank model inference interface.
+    """
+    output = lambda_rank(input_dim, is_infer=True)
+    parameters = paddle.parameters.Parameters.from_tar(gzip.open(model_path))
+
+    infer_query_id = None
+    infer_data = []
+    infer_data_num = 1
+
+    fill_default_test = functools.partial(
+        paddle.dataset.mq2007.test, format="listwise")
+    for label, querylist in fill_default_test():
+        infer_data.append([querylist])
+        if len(infer_data) == infer_data_num:
+            break
+
+    # Predict score of infer_data document.
+    # Re-sort the document base on predict score.
+    # In descending order. then we build the ranking documents.
+    predicitons = paddle.infer(
+        output_layer=output, parameters=parameters, input=infer_data)
+    for i, score in enumerate(predicitons):
+        print i, score
+
+
+def parse_args():
+    parser = argparse.ArgumentParser(
+        description="PaddlePaddle learning to rank example.")
+    parser.add_argument(
+        "--model_type",
+        type=str,
+        help=("A flag indicating to run the RankNet or the LambdaRank model. "
+              "Available options are: ranknet or lambdarank."),
+        default="ranknet")
+    parser.add_argument(
+        "--use_gpu",
+        type=bool,
+        help="A flag indicating whether to use the GPU device in training.",
+        default=False)
+    parser.add_argument(
+        "--trainer_count",
+        type=int,
+        help="The thread number used in training.",
+        default=1)
+    parser.add_argument(
+        "--test_model_path",
+        type=str,
+        required=True,
+        help=("The path of a trained model."))
+    return parser.parse_args()
+
+
+if __name__ == "__main__":
+    args = parse_args()
+    assert os.path.exists(args.test_model_path), (
+        "The trained model does not exit. Please set a correct path.")
+
+    paddle.init(use_gpu=args.use_gpu, trainer_count=args.trainer_count)
+
+    # Training dataset: mq2007, input_dim = 46, dense format.
+    input_dim = 46
+
+    if args.model_type == "ranknet":
+        ranknet_infer(input_dim, args.test_model_path)
+    elif args.model_type == "lambdarank":
+        lambda_rank_infer(input_dim, args.test_model_path)
+    else:
+        logger.fatal(("A wrong value for parameter model type. "
+                      "Available options are: ranknet or lambdarank."))

ltr/lambda_rank.py

@@ -1,32 +1,20 @@
-import os
-import sys
-import gzip
-import functools
-import argparse
-import logging
-import numpy as np
-
+"""
+LambdaRank is a listwise rank model.
+https://papers.nips.cc/paper/2971-learning-to-rank-with-nonsmooth-cost-functions.pdf
+"""
 import paddle.v2 as paddle
 
-logger = logging.getLogger("paddle")
-logger.setLevel(logging.INFO)
-
 
-def lambda_rank(input_dim, is_infer):
+def lambda_rank(input_dim, is_infer=False):
     """
-    LambdaRank is a listwise rank model, the input data and label
-    must be sequences.
+    The input data and label for LambdaRank must be sequences.
 
-    https://papers.nips.cc/paper/2971-learning-to-rank-with-nonsmooth-cost-functions.pdf
     parameters :
       input_dim, one document's dense feature vector dimension
 
     The format of the dense_vector_sequence is as follows:
     [[f, ...], [f, ...], ...], f is a float or an int number
     """
-    if not is_infer:
-        label = paddle.layer.data("label",
-                                  paddle.data_type.dense_vector_sequence(1))
     data = paddle.layer.data("data",
                              paddle.data_type.dense_vector_sequence(input_dim))
 
@@ -49,134 +37,11 @@ def lambda_rank(input_dim, is_infer):
         param_attr=paddle.attr.Param(initial_std=0.01))
 
     if not is_infer:
-        # Define the cost layer.
+        label = paddle.layer.data("label",
+                                  paddle.data_type.dense_vector_sequence(1))
+
         cost = paddle.layer.lambda_cost(
             input=output, score=label, NDCG_num=6, max_sort_size=-1)
-        return cost, output
-    return output
-
-
-def lambda_rank_train(num_passes, model_save_dir):
-    # The input for LambdaRank must be a sequence.
-    fill_default_train = functools.partial(
-        paddle.dataset.mq2007.train, format="listwise")
-    fill_default_test = functools.partial(
-        paddle.dataset.mq2007.test, format="listwise")
-
-    train_reader = paddle.batch(
-        paddle.reader.shuffle(fill_default_train, buf_size=100), batch_size=32)
-    test_reader = paddle.batch(fill_default_test, batch_size=32)
-
-    # Training dataset: mq2007, input_dim = 46, dense format.
-    input_dim = 46
-    cost, output = lambda_rank(input_dim, is_infer=False)
-    parameters = paddle.parameters.create(cost)
-
-    trainer = paddle.trainer.SGD(
-        cost=cost,
-        parameters=parameters,
-        update_equation=paddle.optimizer.Adam(learning_rate=1e-4))
-
-    #  Define end batch and end pass event handler.
-    def event_handler(event):
-        if isinstance(event, paddle.event.EndIteration):
-            logger.info("Pass %d Batch %d Cost %.9f" %
-                        (event.pass_id, event.batch_id, event.cost))
-        if isinstance(event, paddle.event.EndPass):
-            result = trainer.test(reader=test_reader, feeding=feeding)
-            logger.info("\nTest with Pass %d, %s" %
-                        (event.pass_id, result.metrics))
-            with gzip.open(
-                    os.path.join(model_save_dir, "lambda_rank_params_%d.tar.gz"
-                                 % (event.pass_id)), "w") as f:
-                trainer.save_parameter_to_tar(f)
-
-    feeding = {"label": 0, "data": 1}
-    trainer.train(
-        reader=train_reader,
-        event_handler=event_handler,
-        feeding=feeding,
-        num_passes=num_passes)
-
-
-def lambda_rank_infer(test_model_path):
-    """LambdaRank model inference interface.
-
-    Parameters:
-        test_model_path : The path of the trained model.
-    """
-    logger.info("Begin to Infer...")
-    input_dim = 46
-    output = lambda_rank(input_dim, is_infer=True)
-    parameters = paddle.parameters.Parameters.from_tar(
-        gzip.open(test_model_path))
-
-    infer_query_id = None
-    infer_data = []
-    infer_data_num = 1
-
-    fill_default_test = functools.partial(
-        paddle.dataset.mq2007.test, format="listwise")
-    for label, querylist in fill_default_test():
-        infer_data.append([querylist])
-        if len(infer_data) == infer_data_num:
-            break
-
-    # Predict score of infer_data document.
-    # Re-sort the document base on predict score.
-    # In descending order. then we build the ranking documents.
-    predicitons = paddle.infer(
-        output_layer=output, parameters=parameters, input=infer_data)
-    for i, score in enumerate(predicitons):
-        print i, score
-
-
-if __name__ == '__main__':
-    parser = argparse.ArgumentParser(
-        description="PaddlePaddle LambdaRank example.")
-    parser.add_argument(
-        "--run_type",
-        type=str,
-        help=("A flag indicating to run the training or the inferring task. "
-              "Available options are: train or infer."),
-        default="train")
-    parser.add_argument(
-        "--num_passes",
-        type=int,
-        help="The number of passes to train the model.",
-        default=10)
-    parser.add_argument(
-        "--use_gpu",
-        type=bool,
-        help="A flag indicating whether to use the GPU device in training.",
-        default=False)
-    parser.add_argument(
-        "--trainer_count",
-        type=int,
-        help="The thread number used in training.",
-        default=1)
-    parser.add_argument(
-        "--model_save_dir",
-        type=str,
-        required=False,
-        help=("The path to save the trained models."),
-        default="models")
-    parser.add_argument(
-        "--test_model_path",
-        type=str,
-        required=False,
-        help=("This parameter works only in inferring task to "
-              "specify path of a trained model."),
-        default="")
-
-    args = parser.parse_args()
-    paddle.init(use_gpu=args.use_gpu, trainer_count=args.trainer_count)
-    if args.run_type == "train":
-        lambda_rank_train(args.num_passes, args.model_save_dir)
-    elif args.run_type == "infer":
-        assert os.path.exists(args.test_model_path), (
-            "The trained model does not exit. Please set a correct path.")
-        lambda_rank_infer(args.test_model_path)
+        return cost
     else:
-        logger.fatal(("A wrong value for parameter run type. "
-                      "Available options are: train or infer."))
+        return output