* refactor anchors and anchor_grid in Detect Layer

* fix CI failures by adding compatibility

* fix tf failure

* fix different devices errors

* Cleanup

* fix anchors overwriting issue

* better refactoring

* Remove self.anchor_grid shape check (redundant with self.grid check)

Also PEP8 / 120 line width

* Convert _make_grid() from static to dynamic method

* Remove anchor_grid.to(device)

clone() should already clone to same device as self.anchors

* fix different devices error

Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>

* use os.path.relpath instead of relative_to

* use os.path.relpath instead of relative_to

* Remove os.path from val.py

* Remove os.path from train.py

* Update detect.py import to os

* Update export.py import to os

Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>

* Update val.py `pad = 0.0 if task == speed else 0.5`

* Cleanup

* fix different devices bug

* extend _apply() instead of to() for a general fix

* Only apply if Detect() is last layer

Co-authored-by: Jebastin Nadar <njebastin10@gmail.com>

* Indent fix

* Add comment to yolo.py

* Add comment to common.py

Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>

Co-authored-by: qiningonline <qiningonline@gmail.com>

* Requirements updated

1. Requests added to requirements.txt. That might not be included in all docker base images, adding it to the requirements is safer.
2. Added a minimum version to Pandas. It's a good practice to have versions for all dependencies.

* Sort alphabetically

* Update requirements.txt

Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>

* Re-open IP-camera videostream if disconnected. Provide IP-streaming analysis stability

* Re-open IP-camera videostream if disconnected. Provide IP-streaming analysis stability

* `self.imgs[i] *= 0` bug fix and cleanup

Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>

This PR adds a new training argument `--save-period` to save training checkpoints every `x` epochs. To save training every 50 epochs for example:
```
python train.py --save-period 50  # saves epoch50.pt, epoch100.pt, epoch150.pt, ... etc.
```

This saved checkpoints in addition to existing last.pt and best.pt checkpoints and does not affect their behavior. Default value is -1, i.e. disabled.

* Clip TTA Augmented Tails

Experimental TTA update.

* Update yolo.py

* Update yolo.py

* Update yolo.py

* Update yolo.py

* Fix E722, do not use bare 'except'

* Remove used codes

* Add FileNotFoundError in LoadImagesAndLabels

* Remove AssertionError

* Ignore LoadImagesAndLabels

* Ignore downloads.py

* Ignore torch_utils.py

* Ignore train.py

* Ignore datasets.py

* Enable utils/download.py

* Fixing exception in thop

* Remove unused code

* Fixing exception in LoadImagesAndLabels

* Fixing exception in exif_size

* Fixing exception in parse_model

* Ignore exceptions in requests

* Revert the exception as suggested

* Revert the exception as suggested

* added callbacks

* added back callback to main

* added save_dir to callback output

* merged in upstream

* removed ghost code

* added survey

* Update README.md

Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>

* added callbacks

* added back callback to main

* added save_dir to callback output

* merged in upstream

* removed ghost code

* fixed parsing error for google temp links

Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>

* Update ci-testing.yml for Hub custom model tests

* Update ci-testing.yml

`is_valset_wandb_artifact` and `is_trainset_wandb_artifact` were referenced before assignment causing wandb to be unusable.

* added callbacks

* added back callback to main

* added save_dir to callback output

* merged in upstream

* removed ghost code

* added integrations section removed competition

* attempt column build

* attempt column build

* moved new to header

* removed center column

* utm

* Update README.md

* Update README.md

* updated logo sizes

* resized logos

* fixed links

* Update README.md

* Update README.md

* Update README.md

Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>

* Fix relative `ROOT` Pytorch Hub custom model bug

* Update yolo.py

* fix isascii for python3.6

* update comment with python 3.7 note

Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>

* Update relative `ROOT` logic

* python 3.9 Path().is_relative_to() removal

* Allow YOLOv5 execution from arbitrary `cwd`

* Fix str bugs

* Automatic Chinese fonts plotting

* Default PIL=False

`check_file()` is now limited to searching opt-in directories: /data, /models, /utils. This prevents large non-project directories like /.git and /venv from being searched, which may cause `check_file()` to slow significantly.

* Validate best.pt on train end

* 0.7 iou for COCO only

* pass callbacks

* active model.float() if not half

* print Validating best.pt...

* add newline

* Replace `os.system('unzip file.zip')` -> `ZipFile.extractall()`

* Cleanup