以下是Pipelines的主要API的模型介绍，有其他定制化的需求的用户可提issue。
除了DensePassageRetriever的默认模型外，还可以选择下面的模型试试效果：
| 模型 | 语言 | 模型详细信息 |
|---|---|---|
| rocketqa-zh-base-query-encoder | Chinese | 12-layer, 768-hidden, 12-heads, 118M parameters. Trained on DuReader retrieval text. |
| rocketqa-zh-medium-query-encoder | Chinese | 6-layer, 768-hidden, 12-heads, 75M parameters. Trained on DuReader retrieval text. |
| rocketqa-zh-mini-query-encoder | Chinese | 6-layer, 384-hidden, 12-heads, 27M parameters. Trained on DuReader retrieval text. |
| rocketqa-zh-micro-query-encoder | Chinese | 4-layer, 384-hidden, 12-heads, 23M parameters. Trained on DuReader retrieval text. |
| rocketqa-zh-nano-query-encoder | Chinese | 4-layer, 312-hidden, 12-heads, 18M parameters. Trained on DuReader retrieval text. |
| rocketqav2-en-marco-query-encoder | English | 12-layer, 768-hidden, 12-heads, 118M parameters. Trained on MSMARCO. |
类似地ErnieRanker可以选择下面的模型试试效果：
| 模型 | 语言 | 模型详细信息 |
|---|---|---|
| rocketqa-base-cross-encoder | Chinese | 12-layer, 768-hidden, 12-heads, 118M parameters. Trained on DuReader retrieval text. |
| rocketqa-medium-cross-encoder | Chinese | 6-layer, 768-hidden, 12-heads, 75M parameters. Trained on DuReader retrieval text. |
| rocketqa-mini-cross-encoder | Chinese | 6-layer, 384-hidden, 12-heads, 27M parameters. Trained on DuReader retrieval text. |
| rocketqa-micro-cross-encoder | Chinese | 4-layer, 384-hidden, 12-heads, 23M parameters. Trained on DuReader retrieval text. |
| rocketqa-nano-cross-encoder | Chinese | 4-layer, 312-hidden, 12-heads, 18M parameters. Trained on DuReader retrieval text. |
| rocketqav2-en-marco-cross-encoder | English | 12-layer, 768-hidden, 12-heads, 118M parameters. Trained on Trained on MSMARCO. |
ErnieReader目前提供了一个预置的模型：
| 模型 | 语言 | 模型详细信息 |
|---|---|---|
| ernie-gram-zh-finetuned-dureader-robust | Chinese | 12-layer, 768-hidden, 12-heads, 118M parameters. Trained on DuReader Robust Text. |