[Docs] Fix error when building pdf (#1414)

* [Docs] Fix error when building pdf

* fix link

docs/index.rst

@@ -4,7 +4,7 @@ Welcome to MMCV's documentation!
 You can switch between Chinese and English documents in the lower-left corner of the layout.
 
 .. toctree::
-   :maxdepth: 1
+   :maxdepth: 2
    :caption: Get Started
 
    get_started/introduction.md
@@ -12,7 +12,7 @@ You can switch between Chinese and English documents in the lower-left corner of
    get_started/build.md
 
 .. toctree::
-   :maxdepth: 1
+   :maxdepth: 2
    :caption: Understand MMCV
 
    understand_mmcv/config.md
@@ -26,7 +26,7 @@ You can switch between Chinese and English documents in the lower-left corner of
    understand_mmcv/utils.md
 
 .. toctree::
-   :maxdepth: 1
+   :maxdepth: 2
    :caption: Deployment
 
    deployment/onnx.md
@@ -36,26 +36,26 @@ You can switch between Chinese and English documents in the lower-left corner of
    deployment/tensorrt_custom_ops.md
 
 .. toctree::
-   :maxdepth: 1
+   :maxdepth: 2
    :caption: Compatibility
 
    compatibility.md
 
 .. toctree::
-   :maxdepth: 1
+   :maxdepth: 2
    :caption: FAQ
 
    faq.md
 
 .. toctree::
-   :maxdepth: 1
+   :maxdepth: 2
    :caption: Community
 
    community/contributing.md
    community/pr.md
 
 .. toctree::
-   :maxdepth: 1
+   :maxdepth: 2
    :caption: API Reference
 
    api.rst

docs_zh_CN/index.rst

@@ -4,7 +4,7 @@
 您可以在页面左下角切换中英文文档。
 
 .. toctree::
-   :maxdepth: 1
+   :maxdepth: 2
    :caption: 介绍与安装
 
    get_started/introduction.md
@@ -12,7 +12,7 @@
    get_started/build.md
 
 .. toctree::
-   :maxdepth: 1
+   :maxdepth: 2
    :caption: 深入理解 MMCV
 
    understand_mmcv/config.md
@@ -26,7 +26,7 @@
    understand_mmcv/utils.md
 
 .. toctree::
-   :maxdepth: 1
+   :maxdepth: 2
    :caption: 部署
 
    deployment/onnx.md
@@ -36,26 +36,26 @@
    deployment/tensorrt_custom_ops.md
 
 .. toctree::
-   :maxdepth: 1
+   :maxdepth: 2
    :caption: 兼容性
 
    compatibility.md
 
 .. toctree::
-   :maxdepth: 1
+   :maxdepth: 2
    :caption: 常见问题
 
    faq.md
 
 .. toctree::
-   :maxdepth: 1
+   :maxdepth: 2
    :caption: 社区
 
    community/contributing.md
    community/pr.md
 
 .. toctree::
-   :maxdepth: 1
+   :maxdepth: 2
    :caption: API 文档
 
    api.rst

mmcv/ops/correlation.py

@@ -121,8 +121,8 @@ class Correlation(nn.Module):
     where :math:`\star` is the valid 2d sliding window convolution operator,
     and :math:`\mathcal{S}` means shifting the input features (auto-complete
     zero marginal), and :math:`dx, dy` are shifting distance, :math:`dx, dy \in
-    [-\text{max_displacement} \times \text{dilation_patch},
-    \text{max_displacement} \times \text{dilation_patch}]`.
+    [-\text{max\_displacement} \times \text{dilation\_patch},
+    \text{max\_displacement} \times \text{dilation\_patch}]`.
 
     Args:
         kernel_size (int): The size of sliding window i.e. local neighborhood

mmcv/ops/multi_scale_deform_attn.py

@@ -153,9 +153,9 @@ def multi_scale_deformable_attn_pytorch(value, value_spatial_shapes,
 
 @ATTENTION.register_module()
 class MultiScaleDeformableAttention(BaseModule):
-    """An attention module used in Deformable-Detr. `Deformable DETR:
-    Deformable Transformers for End-to-End Object Detection.
+    """An attention module used in Deformable-Detr.
 
+    `Deformable DETR: Deformable Transformers for End-to-End Object Detection.
     <https://arxiv.org/pdf/2010.04159.pdf>`_.
 
     Args: