wai-quantum 0.6.2: the HIP matrix-instruction kernel and the Metal tensor-operation kernel #280

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dcharlot merged 2 commits from wai/quantum-wmma into main 2026-10-17 04:01:04 -04:00

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2026-10-16

Transaction Science

wai-quantum: the Metal member's tensor-operation kernel; M5 measured ...

tensor_ops.metal (metal-tensor-ops-limbs8/..., MetalMember::tensor_ops):
every product formed by the shading language's 4.0 tensor operation
(matmul2d, bf16 accumulated in f32), which the platform maps to the GPU's
matrix hardware where it has it. Each threadgroup owns a scratch slice in
device memory (64x32 limbs, 32x128 weights, 64x128 f32 coefficients); a
64-pair tile is one multiply in four 32-column runs. Offset-binary limbs,
as for the HIP kernel. Family 1007+ under OS 26+, else Unsupported. Eight
mutants. Build records each kernel's language version and scratch.

Measured, silicon:
- family 1009 (M3 Ultra build host / macos runner): 9/9, 66020 probe
  pairs, four pins, 22 qubits, 8 of 8 mutants;
- family 1010 (the only M5 in the fleet, the dev Mac; test binaries
  built on the build host, run once niced): all three Metal kernels 9/9,
  four pins each, 6/6, 7/7 and 8/8 mutants.
With signed limbs instead, the tensor op agrees on all 66020 pairs on
both generations. Off macOS all three suites pass over no device. CI:
a step of wai-quantum-metal and its absent leg.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

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2026-10-16 10:19:30 -04:00

Transaction Science

wai-quantum 0.6.2: the HIP member's matrix-instruction kernel ...

A second HIP kernel for the gate (wmma_limbs.hip, HipMember::wmma), for
the gfx11 architectures: every product formed by the wavefront-of-32
16x16x16 bf16 matrix instruction, accumulated in f32, in the
instruction's own operand layout; one wavefront takes sixteen pairs in
seven 16-column steps.

The instruction's accumulation is not exact once a negative term enters
a sum. Measured on gfx1151, on the instruction alone: 1*1 + (-1)*0
returns 1 - 2^-24, 1 - 1 returns -2^-24, 128 - 64 returns 64 - 2^-17;
non-negative sums are exact. The CUDA kernel's signed top limb fails the
probe there. So the limbs are offset-binary (x + 2^31, all unsigned) and
the kernel removes the offset in 64-bit integers:
e*a = (e+2^31)(a+2^31) - 2^31(e+a) - 2^62 mod 2^64.

Own implementation id (hip-wmma-limbs8/...), HipError::Unsupported for
other architectures, eight mutants (nine-bit limbs, the result rows in
another layout, a wrong offset correction among them).

Measured on gfx1151 (silicon): hip_wmma 9/9, 66020 probe pairs, all four
pins, 22 qubits, 8 of 8 mutants; hip_member 9/9 and hip_sv 3/3
unchanged. With no HIP, both suites pass over no device. CI: a step of
wai-quantum-hip and its absent leg.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

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2026-10-16 10:07:26 -04:00