[QST] Terminology question on GMMA::ScaleOut::One

[haeunlee99]

What does this code do?

tiled_mma.accumulate_ = GMMA::ScaleOut::One;

For example, in "cutlass/include/cutlass/gemm/collective/sm90_mma_tma_gmma_rs_warpspecialized.hpp"

I have no idea when it is set two 1 or 0, it seems random.

[thakkarV]

scales accumulator input by 1 or 0 before

so basically either C += A@B or C = A@B

[haeunlee99]

Why is second tiled_mma.accumulate_ = GMMA::ScaleOut::One; in line 713 necessary?

https://github.com/NVIDIA/cutlass/blob/main/include/cutlass/gemm/collective/sm90_mma_tma_gmma_rs_warpspecialized.hpp

I think this would be enough,

tiled_mma.accumulate_ = GMMA::ScaleOut::Zero;
tiled_mma.accumulate_ = GMMA::ScaleOut::One;

but they are using it this way

tiled_mma.accumulate_ = GMMA::ScaleOut::Zero;
tiled_mma.accumulate_ = GMMA::ScaleOut::One;
tiled_mma.accumulate_ = GMMA::ScaleOut::One;

Why is last one needed?