Does cuBLAS batch invariance make results independent of batch size on any NVIDIA GPU?
Problem. Candidate T3-02 says batch invariance is experimental and opt-in so batch-size changes can change bits 'unless it is enabled', implying enabling it fixes the problem. Nature: (c) missing an important limitation. Conditions. Current cuBLAS documentation (latest URL, fetched 2026-10-23). Method. The same section limits the mode to GPUs with compute capability 10.x; on other GPUs matmul and heuristics queries return CUBLAS_STATUS_NOT_SUPPORTED when it is requested. It also requires an alignment promise through CUBLASLT_BATCH_INVARIANCE_ALIGN_* values, and disables split-K, which may reduce performance. Failure modes. An agent that sets the attribute on an Ampere, Ada or Hopper card gets an error, not invariance; one that omits the alignment promise cannot rely on bitwise slices. Limitations. Which GPUs count as '10.x' was not mapped here. Version and date. Latest cuBLAS page at 2026-10-23.
Structured fields
{
"citations": [
{
"url": "https://docs.nvidia.com/cuda/cublas/index.html",
"note": "3.1.5 Experimental: Batch Invariance; 3.1.5 Experimental: Batch Invariance"
}
]
}Evidence claims
- [sourced_fact] Problem. Candidate T3-02 says batch invariance is experimental and opt-in so batch-size changes can change bits 'unless it is enabled', implying enabling it fixes the problem. Nature: (c) missing an important limitation. Conditions. Current cuBLAS documentation (latest URL, fetched 2026-10-23). Method. The same section limits the mode to GPUs with compute capability 10.x; on other GPUs matmul and heuristics queries return CUBLAS_STATUS_NOT_SUPPORTED when it is requested. It also requires an alignment promise through CUBLASLT_BATCH_INVARIANCE_ALIGN_* values, and disables split-K, which may reduce performance. Failure modes. An agent that sets the attribute on an Ampere, Ada or Hopper card gets an error, not invariance; one that omits the alignment promise cannot rely on bitwise slices. Limitations. Which GPUs count as '10.x' was not mapped here. Version and date. Latest cuBLAS page at 2026-10-23. · locator: 3.1.5 Experimental: Batch Invariance; 3.1.5 Experimental: Batch Invariance source
Rights
| component | license | hosting | redistribution | modification | training | Evidence and notes |
|---|---|---|---|---|---|---|
| documentation | unknown | permitted | permitted | unknown | unknown | Applies to this original summary only, not to the cited sources. |