Remove the CUB/hipCUB direction entirely. Restore Lattice_reduction_gpu.h,
Lattice_reduction_sycl.h, and Lattice_reduction.h to the state before the
CUB rewrite (commit 969b0a39), recovering the original primary function names
(sumD_gpu_small, sumD_gpu_large, sumD_gpu, sum_gpu, sum_gpu_large) and the
hand-rolled shared-memory reduction kernel.
Delete Lattice_reduction_gpu_cub.h. Update Test_reduction to remove the
old/new comparison sections that depended on sum_gpu_old.
The lesson: CUB DeviceReduce is slower than the hand-rolled kernel for small
types, and the smem sizing problem for the extraction pass has no clean
solution within the accelerator_for abstraction. The right improvement is
a higher radix (12 then 4) in sumD_gpu_large, applied directly to the
existing hand-rolled kernel.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Reports us/call and GB/s for sum_gpu (CUB/sycl::reduction) and
sum_gpu_old (hand-rolled shared-memory) for each field type, with
5-call warmup and 100-call timed loop.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Float fields require a grid constructed with vComplexF::Nsimd(); using
a double grid causes grid->_gsites to undercount the sites in float
vobjF, making the constant-field expected value wrong.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
The function computes |sum|^2 — the squared magnitude of an aggregate sum —
not a norm. squaredSum makes clear that squaring is applied to the sum, not
to individual site values before summing, distinguishing it from sumOfSquares
(the squared L2 norm).
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Tests the new CUB/hipCUB/SYCL lattice reduction (sum_gpu) against the
preserved hand-rolled implementation (sum_gpu_old) for LatticeComplexF/D,
LatticeColourMatrixF/D and LatticePropagatorF/D.
Part a) gaussian random field: checks that old and new agree to within
float/double roundoff tolerance.
Part b) constant field (= 1.0, identity-matrix init): verifies
innerProduct(sum, sum) = Ncomp * V^2 where Ncomp counts the nonzero
diagonal scalar components per site (1 / Nc / Ns*Nc respectively).
Make.inc is auto-generated by scripts/filelist on bootstrap and is not
tracked; the new .cc file is all that is needed.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Peter Boyle