Exp

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

Applies the exponential operation to the input data srcReg based on the mask, and writes the result to dstReg. The formula is as follows:

$\text{[math]}$

Prototype

template <typename T = DefaultType, auto mode = MaskMergeMode::ZEROING, typename U>
__simd_callee__ inline void Exp(U& dstReg, U& srcReg, MaskReg& mask)

Parameters

**Table 1** Parameters in the template
Parameter	Description
T	Operand data type. For the Atlas 350 Accelerator Card, the supported data types are half and float.
mode	It can be set to the enumeration of MaskMergeMode or a pointer to a structure of ExpSpecificMode. MaskMergeMode: Set it to MERGING or ZEROING. ZEROING: The elements that are not filtered by mask are set to zero in dstReg. MERGING: This option is not supported currently. ExpSpecificMode is defined as follows: enum class ExpAlgo { INTRINSIC = 0, PRECISION_1ULP_FTZ_TRUE, PRECISION_1ULP_FTZ_FALSE, }; struct ExpSpecificMode{ MaskMergeMode mrgMode = MaskMergeMode::ZEROING, ExpAlgo algo = ExpAlgo::INTRINSIC; }; mrgMode: Set it to MERGING or ZEROING. algo: used to configure the subnormal mode. ExpAlgo::INTRINSIC and ExpAlgo::PRECISION_1ULP_FTZ_TRUE: The result is computed using a single instruction, and all Subnormal numbers are approximated to 0. ExpAlgo::PRECISION_1ULP_FTZ_FALSE: Subnormal data computation is supported.
U	RegTensor type of the source and destination operands, for example, RegTensor<half>. It is automatically inferred by the compiler and does not need to be specified.

**Table 2** 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.

Returns

None

Restrictions

None

Examples

template<typename T>
__simd_vf__ inline void ExpVF(__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;    
    // Subnormal mode
    // static constexpr AscendC::Reg::ExpSpecificMode mode = {Reg::MaskMergeMode::ZEROING, ExpAlgo::PRECISION_1ULP_FTZ_FALSE};
    for (uint16_t i = 0; i < repeatTimes; i++) {
        mask = AscendC::Reg::UpdateMask<T>(count);
        AscendC::Reg::LoadAlign(srcReg, srcAddr + i * oneRepeatSize);
        AscendC::Reg::Exp(dstReg, srcReg, mask);
        // Subnormal mode
        // AscendC::Reg::Exp<T, &mode>(dstReg, srcReg, mask);
        AscendC::Reg::StoreAlign(dstAddr + i * oneRepeatSize, dstReg, mask);
    }
}

Parent topic: Basic Arithmetic