infosave/Lumina-Image-2.0cmf

Lumina-Image 2.0 — CMF (3.3 GB, one file, no Python)

Alpha-VLLM/Lumina-Image-2.0 packed into a single CMF file and run by a pure-Rust engine. No torch, no diffusers, no CUDA install, no C++ toolchain — one binary and one file.

512×512, 30 steps, seed 7, prompt: "a red fox sitting in snow at sunset, photorealistic, detailed fur".

Run it

cargo install cortiq-cli          # pure Rust; needs >= 0.5.54
hf download infosave/Lumina-Image-2.0cmf lumina-q4tp.cmf --local-dir .

cortiq imagine lumina-q4tp.cmf \
  --prompt "a red fox sitting in snow at sunset, photorealistic, detailed fur" \
  --height 512 --width 512 --steps 30 --seed 7 --out fox.ppm

The GPU is used when one is visible — Metal on macOS, Vulkan or DX12 elsewhere. CMF_GPU=0 forces the CPU. Check what the engine sees with cortiq gpu; if it names llvmpipe rather than your card, the Vulkan loader is finding a software driver and the run will be slow.

Output is P6 PPM (no image-library dependency in the engine). Convert with anything: sips -s format png fox.ppm --out fox.png on macOS, convert fox.ppm fox.png with ImageMagick, or ffmpeg -i fox.ppm fox.png.

Flags that matter: --steps (30 is the default and a good trade), --cfg (4.0 default; ≤ 1 disables classifier-free guidance and halves the work at some prompt-adherence cost), --seed, --height/--width (multiples of 16).

Speed

512 × 512, 30 steps, CFG 4, seed 7 — end to end: model load, prompt encode, denoise, VAE decode, file written. Measured 2026-08-06 on cortiq 0.5.54, one run each after a warm-up.

	512 × 512	256 × 256
RTX PRO 6000 Blackwell (Vulkan)	77 s	—
MacBook Air M4, 24 GB (Metal)	219 s	67 s
EPYC 9B45, 48 threads, no GPU	483 s	—

Needs cortiq ≥ 0.5.54 on Vulkan and DX12. Before it, 512 × 512 died on the first step: one SwiGLU dispatch asks for 75060 workgroups and a wgpu dimension holds 65535. 256 × 256 stayed under the cap, which is why this went unnoticed.

The whole-block DiT path is on by default for discrete cards, where it saves host round trips — 77 s against 94 s for the per-op path on the card above. Do not turn it off with CMF_DIT_FUSED=0 on Vulkan: the per-op path renders a visibly different image at 512 × 512 (11.0 dB against the CPU reference, where the fused path is at 28.2 dB). At 256 × 256 the two agree to 58.1 dB.

Which file

Two layouts of the same weights — same 4-bit grid, same images.

file	size	notes
lumina-q4tp.cmf	3.27 GB	take this one. Needs cortiq ≥ 0.5.40
lumina-q4t.cmf	3.45 GB	the older layout, for cortiq < 0.5.40

q4tp keeps the nibbles byte-identical and stores each tile's scale as a 5-bit rung on a per-row ladder instead of a standalone f16 — the scale field was 11% of a q4t file. Rendering speed is unchanged (interleaved at 256px/8 steps on an M4: 26 and 27 s against 27 and 26), and so is the image: 43.6 dB PSNR against the q4t render, 0.31% mean pixel difference.

Any existing .cmf converts in place, no checkpoint needed:

cortiq requant lumina-q4t.cmf --output lumina-q4tp.cmf --quant q4tp

What is in the file

The whole pipeline, not just the transformer: Gemma-2 text encoder + Next-DiT + FLUX VAE + the tokenizer, 888 tensors, 5.27B parameters across the three stages. The diffusers checkpoint this comes from is ~20 GB across four directories; this is 3.2 GB in one mmap-served file that checks its own integrity.

	diffusers	this file
Size	~20 GB	3.2 GB
Files	4 directories	1
Runtime deps	torch + diffusers + transformers	none

Projections are q4_tiled; modulation and embeddings stay q8, the VAE f16, norms f32.

Reproduce the packing

cortiq imagine-pack <diffusers-root> --quant q4t --out lumina-q4t.cmf

<diffusers-root> is the Lumina-Image-2.0 checkout with tokenizer/, text_encoder/, transformer/, vae/. Takes ~9 minutes and streams shard by shard.

Fidelity

The engine mirrors the diffusers Lumina2Pipeline: the system-prompt template, Gemma hidden_states[-2] as caption features, FlowMatchEulerDiscrete with static shift 6, the model called at t = 1 − σ, CFG with per-row norm rescaling and the sign flip before the Euler step.

CPU and GPU renders of the same seed are close but not identical — the CPU path quantizes activations to int8 where the device works in f32, and a flow-matching sampler grows that difference over its steps. On the card above, 4 steps at 512 × 512: 28.2 dB between the two.

What quantization costs against the f32 reference has not been measured on a benchmark. The exact f32 path is cortiq imagine <diffusers-dir> if you need to compare.

License

Apache-2.0, inherited from the base model. Weights © Alpha-VLLM; this repackaging only changes the storage format.

The engine, converter and format spec: https://github.com/infosave2007/cmf