Allow selection of different TPU device

[lalayants]

Allows one to choose TPU device, if multiple are available. I needed this for launching multiple docker containers with Coral Dual Edge TPU with two cores. Without modification, second container raises error, because both are trying to access the first core

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

Allows one to choose TPU device This PR improves code readability by refactoring and restructuring the autobackend.py file.

📊 Key Changes

• Allows one to choose TPU device
• Reformatted and reorganized code for enhanced clarity.
• Added detailed comments to improve code understanding.
• Managed imports for smoother readability.

🎯 Purpose & Impact

• Improved Readability: The changes make the code easier to read and maintain, benefiting developers.
• Functional Changes: This update allows users to choose TPU device.

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

Improved guides and backend support for running Coral Edge TPU models on Raspberry Pi with better TPU management.

📊 Key Changes

• Updated documentation for exporting and running models on Coral Edge TPU.
• Enhanced TPU library handling and version checks in the backend.
• Improved code formatting for better readability and maintenance.

🎯 Purpose & Impact

• User Guidance: Clarifies steps for setting up Coral Edge TPU with Raspberry Pi, ensuring smoother installation and usage.
• Performance Enhancement: Allows selecting multiple TPUs for inference, optimizing resource usage.
• Code Quality: Improved readability and maintainability of backend code, contributing to easier future updates.

[github-actions[bot]]

All Contributors have signed the CLA. ✅
_{Posted by the CLA Assistant Lite bot.}

[lalayants]

I have read the CLA Document and I sign the CLA

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[codecov[bot]]

Codecov Report

Attention: Patch coverage is 40.00000% with 3 lines in your changes missing coverage. Please review.

Project coverage is 72.09%. Comparing base (ccda7ff) to head (a95055c). Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
ultralytics/nn/autobackend.py	0.00%	3 Missing :warning:

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #16576      +/-   ##
==========================================
- Coverage   72.11%   72.09%   -0.02%     
==========================================
  Files         126      126              
  Lines       16506    16507       +1     
==========================================
- Hits        11903    11901       -2     
- Misses       4603     4606       +3     

Flag	Coverage Δ
Benchmarks	35.43% <40.00%> (-0.01%)	:arrow_down:
GPU	29.63% <40.00%> (-0.01%)	:arrow_down:
Tests	68.57% <40.00%> (-0.02%)	:arrow_down:

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[Skillnoob]

Do you have a code example how someone would actually use this to select a different tpu?

[lalayants]

Do you have a code example how someone would actually use this to select a different tpu?

Yeah, below is an example of docker-compose setup. As you can see, you just need to add environment variable TPU_DEVICE. For non-docker usage, just setup it any preferable way.

services:
  yolo_1:
    build:
      context: .
    image: image_name
    container_name: yolo_1
    command: [ "/bin/bash", "-ci", "python3 yolo_test/v8_tpu.py" ]
    ipc: host
    stdin_open: true
    tty: true
    restart: always
    network_mode: host
    working_dir: /workspace/
    privileged: true
    volumes:
      - /etc/localtime:/etc/localtime:ro
      - ./yolo_test:/workspace/yolo_test
    environment:
      TPU_DEVICE: ":0"

   yolo_2:
    image: image_name
    container_name: yolo_2
    command: [ "/bin/bash", "-ci", "python3 yolo_test/v8_tpu.py" ]
    ipc: host
    stdin_open: true
    tty: true
    restart: always
    network_mode: host
    working_dir: /workspace/
    privileged: true
    volumes:
      - /etc/localtime:/etc/localtime:ro
      - ./yolo_test:/workspace/yolo_test
    environment:
      TPU_DEVICE: ":1"

[Skillnoob]

@lalayants I've updated the relevant documentation for your changes.

[Skillnoob]

The device selection now uses the device argument instead of setting a environment variable, which should be much more convenient to use.

[Skillnoob]

@Laughing-q this is ready for review.

[Laughing-q]

@lalayants @Skillnoob I noticed besides the actual changes this PR are making there are a lot code format updates, for example: Can we revert that?

[Skillnoob]

Yeah, the code formats can be reverted, they weren't done by me. I'm able to do that in a few hours when I can get on my pc.

[Skillnoob]

@Laughing-q I've removed the unnecessary reformat.

[Laughing-q]

@Skillnoob @lalayants Looks good to me!

[Skillnoob]

@glenn-jocher This is ready to merge

[glenn-jocher]

@Skillnoob @Laughing-q @lalayants thank you all! PR merged :)