CUBLAS_COMPUTE_32F_FAST_TF32 returns NOT_SUPPORTED on RTX 3050 (SM86)
for certain (m,n,k) via cublasLtMatmul (e.g., 128×512×64). Plain
CUBLAS_COMPUTE_32F works for all dimensions. TF32 tensor cores are
still enabled via CUBLAS_TF32_TENSOR_OP_MATH math mode on the cuBLAS
handle — this activates TF32 on Ampere+ automatically when the
hardware supports the specific matrix dimensions.
Also: use sys::cublasLtMatmul directly (bypass result:: wrapper)
for clearer argument ordering.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>