Nf4 Normal Float 4 Bit Quantization With Information Theoretic Optimality

via “nf4 (normal float 4-bit) quantization with information-theoretic optimality”

8-bit and 4-bit quantization enabling QLoRA fine-tuning.

Unique: Uses information-theoretically optimal quantization levels derived from inverse normal CDF, allocating more precision to high-probability regions of weight distributions. Achieves better accuracy than uniform FP4 quantization on transformer weights without requiring per-layer calibration.

vs others: Outperforms FP4 quantization on transformer models by 1-2% accuracy while maintaining same memory footprint, and requires no calibration unlike post-training quantization methods.