Standardize batch format. Introduce batch postprocessing.

[ibro45]

Description

Defined a clear batch format requirement. A batch must be a Dict containing "input" (required), "target" (optional), and/or "id" (optional).

Simplified the criterion calculation - "target" will be passed to the criterion if it's in the batch instead of checking if criterion has a target argument.

LighterSystem's postprocessing now includes batch in addition to the existing criterion, metrics, and logging. This allows easy manipulation of the batch data primarily to get it in the correct format where that is not possible/convenient with Transforms - for example torchvision's CIFAR10 dataset.

Related Issue

None

Type of Change

• 📚 Examples / docs / tutorials / dependencies update
• 🔧 Bug fix (non-breaking change which fixes an issue)
• 🥂 Improvement (non-breaking change which improves an existing feature)
• 🚀 New feature (non-breaking change which adds functionality)
• 💥 Breaking change (fix or feature that would cause existing functionality to change)
• 🔐 Security fix

Checklist

• I've read the CODE_OF_CONDUCT.md document.
• I've read the CONTRIBUTING.md guide.
• I've updated the code style using make codestyle.
• I've written tests for all new methods and classes that I created.
• I've written the docstring in Google format for all the methods and classes that I used.