PairReduceElem

Applicability

Product	Supported
Atlas 350 Accelerator Card	√
Atlas A3 training product/Atlas A3 inference product	x
Atlas A2 training product/Atlas A2 inference product	x
Atlas 200I/500 A2 inference product	x
Atlas inference product AI Core	x
Atlas inference product Vector Core	x
Atlas training product	x

Function Usage

Adds two adjacent values in the passed srcReg and saves the result in the lower bits of dstReg.

Prototype

template <PairReduce type = PairReduce::SUM, typename T = DefaultType, MaskMergeMode mode = MaskMergeMode::ZEROING, typename U>
__simd_callee__ inline void PairReduceElem(U& dstReg, U srcReg, MaskReg mask)

Parameters

**Table 1** Template parameters
Parameter	Description
type	Specific PairReduce type. Currently, only sum reduction is supported. enum class PairReduce { SUM = 0, };
T	Data type of the destination and source operands. For the Atlas 350 Accelerator Card, the supported data types are half and float.
mode	Set it to MERGING or ZEROING. ZEROING: The elements that are not filtered by mask are set to zero in dst. Currently, only this mode is supported.
U	RegTensor type of the destination and source operands. It is automatically inferred by the compiler and does not need to be specified.

**Table 2** Function parameters
Parameter	Input/Output	Description
dstReg	Output	Destination operand. The type is RegTensor.
srcReg	Input	Source operand. The type is RegTensor. The source operand must have the same data type as the destination operand.
mask	Input	Valid indication of the source operand element operation. For details, see MaskReg.

Constraints

None

Example

template<typename T>
__simd_vf__ inline void PairReduceElemVF(__ubuf__ T* dstAddr, __ubuf__ T* srcAddr, uint32_t count, 
 uint32_t oneRepeatSize, uint16_t repeatTimes)
{
    AscendC::Reg::RegTensor<T> srcReg;
    AscendC::Reg::RegTensor<T> dstReg;
    AscendC::Reg::MaskReg mask;
    for (uint16_t i = 0; i < repeatTimes; i++) {
        AscendC::Reg::LoadAlign(srcReg, srcAddr + i * oneRepeatSize);
        mask = AscendC::Reg::UpdateMask<T>(count);
        AscendC::Reg::PairReduceElem<AscendC::Reg::PairReduce::SUM>(dstReg, srcReg, mask);
        AscendC::Reg::StoreAlign(dstAddr + i * oneRepeatSize, dstReg, mask);
    }
}

Parent topic: Reduction Computation