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    <img src="https://raw.githubusercontent.com/open-mmlab/mmcv/master/docs/mmcv-logo.png" width="300"/>
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## Introduction

MMCV is a foundational python library for computer vision research and supports many
research projects as below:

- [MMDetection](https://github.com/open-mmlab/mmdetection): Detection toolbox and benchmark
- [MMDetection3D](https://github.com/open-mmlab/mmdetection3d): General 3D object detection toolbox and benchmark
- [MMSegmentation](https://github.com/open-mmlab/mmsegmentation): Semantic segmentation toolbox and benchmark
- [MMEditing](https://github.com/open-mmlab/mmediting): Image and video editing toolbox
- [MMPose](https://github.com/open-mmlab/mmpose): Pose estimation toolbox and benchmark
- [MMAction2](https://github.com/open-mmlab/mmaction2): Action understanding toolbox and benchmark
- [MMClassification](https://github.com/open-mmlab/mmclassification): Image classification toolbox and benchmark

It provides the following functionalities.

- Universal IO APIs
- Image/Video processing
- Image and annotation visualization
- Useful utilities (progress bar, timer, ...)
- PyTorch runner with hooking mechanism
- Various CNN architectures
- High-quality implementation of common CUDA ops

See the [documentation](http://mmcv.readthedocs.io/en/latest) for more features and usage.

Note: MMCV requires Python 3.6+.

## Installation

There are two versions of MMCV:

- **mmcv**: lite, without CUDA ops but all other features, similar to mmcv<1.0.0. It is useful when you do not need those CUDA ops.
- **mmcv-full**: comprehensive, with full features and various CUDA ops out of box. It takes longer time to build.

**Note**: Do not install both versions in the same environment, otherwise you may encounter errors like `ModuleNotFound`. You need to uninstall one before installing the other.

a. Install the lite version.

```python
pip install mmcv
```

b. Install the full version.

Before installing mmcv-full, make sure that PyTorch has been successfully installed following the [official guide](https://pytorch.org/).

We provide pre-built mmcv packages (recommended) with different PyTorch and CUDA versions to simplify the building.

i. Install the latest version.

The rule for installing the latest ``mmcv-full`` is as follows:

```shell
pip install mmcv-full -f https://download.openmmlab.com/mmcv/dist/{cu_version}/{torch_version}/index.html
```

Please replace ``{cu_version}`` and ``{torch_version}`` in the url to your desired one. For example,
to install the latest ``mmcv-full`` with ``CUDA 11`` and ``PyTorch 1.7.0``, use the following command:

```shell
pip install mmcv-full -f https://download.openmmlab.com/mmcv/dist/cu110/torch1.7.0/index.html
```

For more details, please refer the the following tables and delete ``=={mmcv_version}``.

ii. Install a specified version.

The rule for installing a specified ``mmcv-full`` is as follows:

```shell
pip install mmcv-full=={mmcv_version} -f https://download.openmmlab.com/mmcv/dist/{cu_version}/{torch_version}/index.html
```

First of all, please refer to the Releases and replace ``{mmcv_version}`` a specified one. e.g. ``1.2.2``.
Then replace ``{cu_version}`` and ``{torch_version}`` in the url to your desired versions. For example,
to install ``mmcv-full==1.2.2`` with ``CUDA 11`` and ``PyTorch 1.7.0``, use the following command:

```shell
pip install mmcv-full==1.2.2 -f https://download.openmmlab.com/mmcv/dist/cu110/torch1.7.0/index.html
```

For more details, please refer the the following tables.

<table class="docutils">
  <tbody>
    <tr>
      <th width="80"> CUDA </th>
      <th valign="bottom" align="left" width="100">torch 1.7</th>
      <th valign="bottom" align="left" width="100">torch 1.6</th>
      <th valign="bottom" align="left" width="100">torch 1.5</th>
      <th valign="bottom" align="left" width="100">torch 1.4</th>
      <th valign="bottom" align="left" width="100">torch 1.3</th>
    </tr>
    <tr>
      <td align="left">11.0</td>
      <td align="left"><details><summary> install </summary><pre><code>pip install mmcv-full=={mmcv_version} -f https://download.openmmlab.com/mmcv/dist/cu110/torch1.7.0/index.html</code></pre> </details> </td>
      <td align="left"> </td>
      <td align="left"> </td>
      <td align="left"> </td>
      <td align="left"> </td>
    </tr>
    <tr>
      <td align="left">10.2</td>
      <td align="left"><details><summary> install </summary><pre><code>pip install mmcv-full=={mmcv_version} -f https://download.openmmlab.com/mmcv/dist/cu102/torch1.7.0/index.html</code></pre> </details> </td>
      <td align="left"><details><summary> install </summary><pre><code>pip install mmcv-full=={mmcv_version} -f https://download.openmmlab.com/mmcv/dist/cu102/torch1.6.0/index.html</code></pre> </details> </td>
      <td align="left"><details><summary> install </summary><pre><code>pip install mmcv-full=={mmcv_version} -f https://download.openmmlab.com/mmcv/dist/cu102/torch1.5.0/index.html</code></pre> </details> </td>
      <td align="left"> </td>
      <td align="left"> </td>
    </tr>
    <tr>
      <td align="left">10.1</td>
      <td align="left"><details><summary> install </summary><pre><code> pip install mmcv-full=={mmcv_version} -f https://download.openmmlab.com/mmcv/dist/cu101/torch1.7.0/index.html</code></pre> </details> </td>
      <td align="left"><details><summary> install </summary><pre><code> pip install mmcv-full=={mmcv_version} -f https://download.openmmlab.com/mmcv/dist/cu101/torch1.6.0/index.html</code></pre> </details> </td>
      <td align="left"><details><summary> install </summary><pre><code> pip install mmcv-full=={mmcv_version} -f https://download.openmmlab.com/mmcv/dist/cu101/torch1.5.0/index.html</code></pre> </details> </td>
      <td align="left"><details><summary> install </summary><pre><code>pip install mmcv-full=={mmcv_version} -f https://download.openmmlab.com/mmcv/dist/cu101/torch1.4.0/index.html</code></pre> </details> </td>
      <td align="left"><details><summary> install </summary><pre><code>pip install mmcv-full=={mmcv_version} -f https://download.openmmlab.com/mmcv/dist/cu101/torch1.3.0/index.html</code></pre> </details> </td>
    </tr>
    <tr>
      <td align="left">9.2</td>
      <td align="left"><details><summary> install </summary><pre><code> pip install mmcv-full=={mmcv_version} -f https://download.openmmlab.com/mmcv/dist/cu92/torch1.7.0/index.html</code></pre> </details> </td>
      <td align="left"><details><summary> install </summary><pre><code> pip install mmcv-full=={mmcv_version} -f https://download.openmmlab.com/mmcv/dist/cu92/torch1.6.0/index.html</code></pre> </details> </td>
      <td align="left"><details><summary> install </summary><pre><code> pip install mmcv-full=={mmcv_version} -f https://download.openmmlab.com/mmcv/dist/cu92/torch1.5.0/index.html</code></pre> </details> </td>
      <td align="left"><details><summary> install </summary><pre><code>pip install mmcv-full=={mmcv_version} -f https://download.openmmlab.com/mmcv/dist/cu92/torch1.4.0/index.html</code></pre> </details> </td>
      <td align="left"><details><summary> install </summary><pre><code>pip install mmcv-full=={mmcv_version} -f https://download.openmmlab.com/mmcv/dist/cu92/torch1.3.0/index.html</code></pre> </details> </td>
    </tr>
    <tr>
      <td align="left">cpu</td>
      <td align="left"><details><summary> install </summary><pre><code> pip install mmcv-full=={mmcv_version} -f https://download.openmmlab.com/mmcv/dist/cpu/torch1.7.0/index.html</code></pre> </details> </td>
      <td align="left"><details><summary> install </summary><pre><code> pip install mmcv-full=={mmcv_version} -f https://download.openmmlab.com/mmcv/dist/cpu/torch1.6.0/index.html</code></pre> </details> </td>
      <td align="left"><details><summary> install </summary><pre><code> pip install mmcv-full=={mmcv_version} -f https://download.openmmlab.com/mmcv/dist/cpu/torch1.5.0/index.html</code></pre> </details> </td>
      <td align="left"><details><summary> install </summary><pre><code>pip install mmcv-full=={mmcv_version} -f https://download.openmmlab.com/mmcv/dist/cpu/torch1.4.0/index.html</code></pre> </details> </td>
      <td align="left"><details><summary> install </summary><pre><code>pip install mmcv-full=={mmcv_version} -f https://download.openmmlab.com/mmcv/dist/cpu/torch1.3.0/index.html</code></pre> </details> </td>
    </tr>
  </tbody>
</table>

Another way is to compile locally by running

```python
pip install mmcv-full
```

c. Install full version with custom operators for onnxruntime

- Check [here](docs/onnxruntime_op.md) for detailed instruction.

Note that the local compiling may take up to 10 mins.

If you would like to build MMCV from source, please refer to the [guide](https://mmcv.readthedocs.io/en/latest/build.html).

## FAQ

If you face some installation issues, CUDA related issues or RuntimeErrors,
you may first refer to this [Trouble Shooting Page](https://mmcv.readthedocs.io/en/latest/trouble_shooting.html).
