ms2_dense_mean

This is a copy of the [MS^2](https://huggingface.co/datasets/allenai/mslr2022) dataset, except the input source documents of its `train`, `validation` and `test` splits have been replaced by a __dense__ retriever. The retrieval pipeline used:

- __query__: The `background` field of each example
- __corpus__: The union of all documents in the `train`, `validation` and `test` splits. A document is the concatenation of the `title` and `abstract`.
- __retriever__: [`facebook/contriever-msmarco`](https://huggingface.co/facebook/contriever-msmarco) via [PyTerrier](https://pyterrier.readthedocs.io/en/latest/) with default settings
- __top-k strategy__: `"max"`, i.e. the number of documents retrieved, `k`, is set as the maximum number of documents seen across examples in this dataset, in this case `k==17`

Retrieval results on the `train` set:

| Recall@100 | Rprec | Precision@k | Recall@k |
| ----------- | ----------- | ----------- | ----------- |
| 0.4764 | 0.2395 | 0.2271 | 0.2418 |

Retrieval results on the `validation` set:

| Recall@100 | Rprec | Precision@k | Recall@k |
| ----------- | ----------- | ----------- | ----------- |
| 0.4364 | 0.2125 | 0.2131 | 0.2074 |

Retrieval results on the `test` set:

| Recall@100 | Rprec | Precision@k | Recall@k |
| ----------- | ----------- | ----------- | ----------- |
| 0.4481 | 0.2224 | 0.2254 | 0.2100 |

本数据集为[MS^2](https://huggingface.co/datasets/allenai/mslr2022)的复刻版本，仅将其`train`（训练集）、`validation`（验证集）与`test`（测试集）划分的输入源文档替换为**稠密（dense）**检索器所获取的文档。所采用的检索流程如下：
- **查询（query）**：每个示例的`background`（背景）字段
- **语料库（corpus）**：`train`、`validation`和`test`划分中所有文档的合集，单篇文档由`title`（标题）与`abstract`（摘要）拼接得到
- **检索器（retriever）**：基于[PyTerrier](https://pyterrier.readthedocs.io/en/latest/)框架，采用默认参数配置的[`facebook/contriever-msmarco`](https://huggingface.co/facebook/contriever-msmarco)模型
- **Top-K策略（top-k strategy）**：采用`"max"`策略，即检索返回的文档数`k`设置为该数据集所有示例中所需的最大文档数，本次任务中`k=17`

训练集检索结果：
| 召回率@100（Recall@100） | R准确率（Rprec） | 精确率@k（Precision@k） | 召回率@k（Recall@k） |
| ----------- | ----------- | ----------- | ----------- |
| 0.4764 | 0.2395 | 0.2271 | 0.2418 |

验证集检索结果：
| 召回率@100（Recall@100） | R准确率（Rprec） | 精确率@k（Precision@k） | 召回率@k（Recall@k） |
| ----------- | ----------- | ----------- | ----------- |
| 0.4364 | 0.2125 | 0.2131 | 0.2074 |

测试集检索结果：
| 召回率@100（Recall@100） | R准确率（Rprec） | 精确率@k（Precision@k） | 召回率@k（Recall@k） |
| ----------- | ----------- | ----------- | ----------- |
| 0.4481 | 0.2224 | 0.2254 | 0.2100 |