Quantization-Aware Training in Large Language Models: How Fake Quantization, STE, and Learned Step Sizes Preserve Low-Bit Accuracy
Quantization-Aware Training (QAT) is a model compression paradigm that integrates precision loss directly into the training or fine-tuning graph. While Post-Training Quantization (PTQ) calibrates fixed floating-point weights without updating underlying network parameters, QAT simulates the numerical discretization of weights, activations, and key-value (KV) caches during both forward and backward passes. This closed-loop optimization forces neural network weights to co-adapt to discrete integer

