ggml-org/llama.cpp b11851

on GitHub

mtmd : lfm2 resize matches torchvision (#30943)

• mtmd : lfm2 bilinear resize matches torchvision

Lfm2VlImageProcessor and d1-omni vision.py resize uint8 images with
torchvision (antialias=True). That is Pillow's algorithm, except that the
weights are int16 with as many fractional bits as the largest weight allows,
where Pillow uses 22 bits. The Pillow port was 1-2 levels off on about 1% of
the values of the d1-omni and LFM2.5-VL crops.

RESIZE_ALGO_BILINEAR_TORCH rounds the weights of the Pillow port to that
precision and scales them back to 22 bits, which gives the output of
torchvision with the same passes, and "bilinear" maps to it for LFM2 and
d1-omni. Other models keep the Pillow algorithms.

• mtmd : lfm2 bicubic resize matches torchvision

Lfm2VlImageProcessor resizes with torchvision for the bicubic checkpoints too
(d1-3B, LFM2-VL), so "bicubic" maps to RESIZE_ALGO_BICUBIC_TORCH for LFM2: the
Pillow bicubic filter (a = -0.5, as torchvision with antialias) with the int16
weights of torchvision. The Pillow port was 1-2 levels off on about 0.25% of
the values of the d1-3B crops.

• use bitfield, add hparams setter

Co-authored-by: Xuan Son Nguyen son@huggingface.co