adithya-balaji/rfdetr-cpp-small

RF-DETR Small — GGUF for rfdetr.cpp

GGUF-format weights of Roboflow RF-DETR Small (detection variant) for use with rfdetr.cpp, a C++/ggml implementation that matches the upstream PyTorch model on CPU.

This repo contains all four standard quantizations of this variant. F16 is the recommended default — same accuracy as F32, 1.85× smaller, and typically the fastest on modern CPUs thanks to ggml's F32×F16 matmul fast path.

Available files

File	Quant	Size (MB)	Recall @ IoU 0.5	Recall @ IoU 0.95	Mean |Δscore|	Latency (median ms, T=8)
rfdetr-small-f32.gguf	F32	119.0	0.9762	0.9762	0.0012	100.1
rfdetr-small-f16.gguf ← recommended	F16	64.0	0.9762	0.9762	0.0013	94.3
rfdetr-small-q8_0.gguf	Q8_0	38.2	0.9476	0.9476	0.0041	110.2
rfdetr-small-q4_K.gguf	Q4_K	31.2	0.9238	0.8286	0.0206	116.0

All accuracy numbers above are computed against the upstream PyTorch reference (rfdetr 1.9.0) on 7 images (000000000139.jpg, 000000000632.jpg, 000000039769.jpg, 000000087038.jpg, 000000252219.jpg, 000000397133.jpg, bus.jpg) at threshold 0.5. Latency is measured separately with rfdetr-cli bench (8 iters + 3 warmup) at T=8 threads on a single Intel Core i7-12800HX, on tests/fixtures/ci/test_image.jpg.

Architecture

• Backbone: DINOv2-small
• Input resolution: 512×512
• Patch size: 16
• Decoder layers: 3
• Object queries: 300
• Task: object detection (boxes only)

Quantization notes

• F32 — full-precision reference, ~120 MB. Bit-exact PyTorch parity.
• F16 — matmul-multiplicand weights only; LayerNorms, conv kernels, embeddings, biases, and layer-scale gammas stay F32. Lossless on this model and consistently the fastest variant on CPU.
• Q8_0 — best size/accuracy tradeoff under F16; ~3× smaller than F32 with effectively identical detections.
• Q4_K — smallest practical quant. Rows with ne[0] % 256 != 0 (the decoder's 128-dim MLP halves, 60 tensors) silently fall back to Q8_0 per ggml's quantizer logic — net compression is still ~3.8× over F32. Use only when the size budget is tight; expect a measurable Recall@0.95 drop relative to F16/Q8_0 (see file table above).

Compatibility

These GGUFs stamp rfdetr.preprocess.resize_mode = "bilinear_no_antialias", matching RF-DETR 1.9's antialias-free float bilinear resize (align_corners=false, half-pixel coordinates, no intermediate uint8 rounding). rf-detr.cpp treats this key as optional: GGUFs that predate this metadata (no resize_mode key) keep using the legacy stb-based resize path, so older files continue to produce their original outputs unchanged. An unrecognized resize_mode value is rejected rather than guessed.

Keypoint-preview inference is not supported. rf-detr.cpp does not implement the keypoint output head; this repository only serves box detection outputs.

Usage

# 1. Clone + build rfdetr.cpp
git clone https://github.com/adithyab94/rf-detr.cpp
cd rf-detr.cpp
cmake -B build -DRFDETR_BUILD_CLI=ON && cmake --build build -j

# 2. Download a quant (F16 recommended)
hf download adithya-balaji/rfdetr-cpp-small rfdetr-small-f16.gguf --local-dir models/

# 3. Run detection
build/bin/rfdetr-cli detect \
    --model models/rfdetr-small-f16.gguf \
    --input my_image.jpg \
    --threshold 0.5 --threads 8 \
    --output detections.json

Accuracy methodology

All accuracy metrics are computed against the upstream PyTorch reference (rfdetr 1.9.0) on 7 images (000000000139.jpg, 000000000632.jpg, 000000039769.jpg, 000000087038.jpg, 000000252219.jpg, 000000397133.jpg, bus.jpg) at threshold 0.5. Each detection match uses greedy Hungarian-style assignment by IoU (≥ 0.5 lenient, ≥ 0.95 strict) with class equality required.

See BENCHMARK.md and benchmarks/results/accuracy_sweep.json for the full sweep across the (variant × quant) cells.

Provenance

• Source project: Roboflow RF-DETR
• Upstream package: rfdetr==1.9.0
• Converted with rfdetr.cpp at commit fbef9387bed3
• Checkpoint: official pretrained rfdetr-small weights (downloaded by the rfdetr package on first use)

Checksums (SHA-256)

Also available as SHA256SUMS in this repo.

1cae02bb13c1361b46ce44c8cf3b4086243fddbf74173994fbb7723aa1a16746  rfdetr-small-f32.gguf
9da8e657f7554313e1fd0fad1b0105db508f0e9321b02ac4dd5836f17466e408  rfdetr-small-f16.gguf
202de9f52ab46bd112d15f5960797ec103d70a18e88a326d501ee150aa98863b  rfdetr-small-q8_0.gguf
5bf496385c471cd65443fc9d4043b9c6cd6d52d1595d19fdd89f107760f9e08d  rfdetr-small-q4_K.gguf

License

Apache-2.0 — matches the upstream rfdetr license.