orbitquant-9c2a21de·1 events·first seen Aliases: OrbitQuant
OrbitQuant is a new post-training quantization method for diffusion transformers that avoids the need for calibration data by quantizing activations in a normalized, rotated basis using a randomized permuted block-Hadamard rotation. A single Lloyd-Max codebook covers all timesteps, prompts, and layers for a given input dimension, and the same recipe transfers from image to video models without per-modality tuning. The method is evaluated on FLUX.1, Z-Image-Turbo, Wan 2.1, and CogVideoX, claiming state-of-the-art PTQ results at several low-bit settings including W2A4 for image DiTs.