Validation

Local source validation covers NVIDIA GeForce RTX 5090 (SM120) and NVIDIA Jetson AGX Thor (SM110).

python fp4-gemm/tests/test_fp4_gemm.py \
  --backend source \
  --mode full \
  --json-out internal-tests/fp4-gemm-source-full.json

Result:

SM120 full gate: 25/25 checks passed, including all fused epilogues and the aggregate BF16 direct-producer layout gate.
SM110 model-shape gate: 24/24 checks passed across PI0.5, GROOT, Cosmos Edge, and LingBot VLA projection shapes.
Variants 0, 1, and 2 were checked.
SM110 additionally checks production auto-dispatch (variant=-1).
nvfp4_gemm_bf16 is the canonical public API.
Correctness reference dequantizes the same FP4/SFA and FP4/SFB inputs used by the kernel, then computes PyTorch GEMM on those dequantized values.
The direct BF16 producer is byte-exact against the established BF16-to-FP16 plus FP16-producer contract for packed E2M1, mapped SFA/SFB bytes, and dequantized output. Covered activation shapes are (1,5120), (1,6144), (1,17408), (16,2048), and (128,512); SFB coverage uses (64,1024).

Shape	Variant	Cosine
M=16, N=128, K=128	0	1.0
M=16, N=128, K=128	1	1.0
M=16, N=128, K=128	2	1.0
M=32, N=256, K=256	0	1.0
M=32, N=256, K=256	1	1.0
M=32, N=256, K=256	2	1.0
M=64, N=512, K=512	0	1.0
M=64, N=512, K=512	1	1.0
M=64, N=512, K=512	2	1.0

Installed Artifact Validation

The local kernel-builder release candidate produced and passed ABI, manylinux, layout, and builder get_kernel checks for:

torch211-cxx11-cu128-x86_64-linux
torch211-cxx11-cu130-x86_64-linux
torch212-cxx11-cu130-x86_64-linux
torch212-cxx11-cu132-x86_64-linux

The cu128/Torch 2.11 artifact passed 10/10 runtime gates: all nine shape/variant correctness rows were exact against the staged reference, and the public nvfp4_gemm_bf16 wrapper was exact under torch.compile(fullgraph=True).

The SM110 release flake pins kernel-builder commit d720fa90fb9cd92d1bc60a9dc5c55bef2aafabb8, which includes CUTLASS 4.5 support and the corrected CUTLASS 4.5.2 fixed-output hash. HF Jobs, the SM110 aarch64 artifact build, and cold Hub loads must pass before the rebuilt Hub release is considered complete.

BF16 Direct Producer

RTX 5090, 100 warmup iterations and 1000 measured iterations:

Shape	BF16 direct	BF16 cast + FP16 producer	Speedup	Native BF16 producer	Hub/native
M=1, K=5120	4.098 us	6.404 us	1.563x	6.150 us	0.666x
M=1, K=6144	4.098 us	6.403 us	1.562x	8.190 us	0.500x
M=1, K=17408	4.096 us	6.413 us	1.566x	18.442 us	0.222x

The native BF16 producer is included as a latency comparison but uses a different FlashRT quantization strategy. Correctness acceptance is therefore against this package's established FP16 producer contract, where all tested packed and mapped scale bytes are exact.

Thor Native Parity

The Tensor wrapper was compared against the same native FlashRT launchers on Thor with 20 warmup and 100 measured iterations. For production auto-dispatch across the six model shapes, wrapper/native latency ratio had median 1.019 and maximum 1.086. Correctness was exact (max_abs=mean_abs=p99_abs=0).