Abs

Applicability

Product	Supported/Unsupported
Atlas A3 training products / Atlas A3 inference products	√
Atlas A2 training products / Atlas A2 inference products	√
Atlas 200I/500 A2 inference products	√
Atlas inference product 's AI Core	√
Atlas inference product 's Vector Core	x
Atlas training products	√

Functions

Computes the absolute value of each element. The formula is as follows:

$\text{[math]}$

Prototype

Computation of the first n pieces of data of a tensor

        
             template <typename T>
__aicore__ inline void Abs(const LocalTensor<T>& dst, const LocalTensor<T>& src, const int32_t& count)

High-dimensional tensor sharding computation

Bitwise mask mode

          
               template <typename T, bool isSetMask = true>
__aicore__ inline void Abs(const LocalTensor<T>& dst, const LocalTensor<T>& src, uint64_t mask[], const uint8_t repeatTime, const UnaryRepeatParams& repeatParams)

Contiguous mask mode

          
               template <typename T, bool isSetMask = true>
__aicore__ inline void Abs(const LocalTensor<T>& dst, const LocalTensor<T>& src, uint64_t mask, const uint8_t repeatTime, const UnaryRepeatParams& repeatParams)

Parameters

**Table 1** Parameters in the template
Parameter	Description
T	Operand data type. For the Atlas A3 training products / Atlas A3 inference products , the supported data types are half and float. For the Atlas A2 training products / Atlas A2 inference products , the supported data types are half and float. Atlas 200I/500 A2 inference products : The supported data types are int16_t, half, and float. For the Atlas inference product 's AI Core, the supported data types are half and float. For the Atlas training products , the supported data types are half and float.
isSetMask	Indicates whether to set mask inside the API. true: sets mask inside the API. false: sets mask outside the API. Developers need to use the SetVectorMask API to set the mask value. In this mode, the mask value in the input parameter of this API must be set to the placeholder MASK_PLACEHOLDER.

**Table 2** Parameters
Parameter	Input/Output	Description
dst	Output	Destination operand. The type is LocalTensor, and the supported TPosition is VECIN, VECCALC, or VECOUT. The start address of the LocalTensor must be 32-byte aligned.
src	Input	Source operand. The type is LocalTensor, and the supported TPosition is VECIN, VECCALC, or VECOUT. The start address of the LocalTensor must be 32-byte aligned. The source operand must have the same data type as the destination operand.
count	Input	Number of elements involved in the computation.
mask[]/mask	Input	The mask parameter is used to control the elements involved in computation in each iteration. Bitwise mode: controls the elements that participate in computation by bit. If a bit is set to 1, the corresponding element participates in the computation. If a bit is set to 0, the corresponding element is masked in the computation. The mask is in array form. The array length and the value range of the array elements are related to the data type of the operand. When the operand is 16-bit, the array length is 2. In this case, mask[0] and mask[1] must be in the range of [0, 2⁶⁴ – 1] and cannot be 0 at the same time. When the operand is 32-bit, the array length is 1. In this case, mask[0] must be in the range of (0, 2⁶⁴ – 1]. When the operand is 64-bit, the array length is 1. In this case, mask[0] must be in the range of (0, 2³² – 1]. For example, if mask = [0, 8] and 8 = 0b1000, only the fourth element participates in computation. Contiguous mode: indicates the number of contiguous elements that participate in computation. The value range is related to the operand data type. The maximum number of elements that can be processed in each repeat varies according to the data type. When the operand is 16-bit, mask ∈ [1, 128]. When the operand is 32-bit, mask ∈ [1, 64]. When the operand is 64-bit, mask ∈ [1, 32].
repeatTime	Input	Number of iteration repeats. The Vector Unit reads 256 bytes of contiguous data for computation each time. To read the complete data for processing, the unit needs to read the input data in multiple repeats. repeatTime indicates the number of iteration repeats. For details about this parameter, see High-dimensional Sharding APIs.
repeatParams	Input	Parameters that control the operand address strides. They are of the UnaryRepeatParams type, and contain such parameters as those that specify the address stride of the operand for the same data block between adjacent iterations and address stride of the operand between different data blocks in a single iteration. For details about the address stride parameters between adjacent iterations, see repeatStride. For details about the address stride parameters of DataBlock in the same iteration, see dataBlockStride.

Returns

None

Constraints

For details about the operand address alignment requirements, see General Address Alignment Restrictions.
For details about the operand address overlapping restrictions, see General Address Overlap Restrictions.

Examples

For more examples, see here.

Example of high-dimensional tensor sharding computation (contiguous mask mode), where both srcLocal and dstLocal are of the half type.

        
             uint64_t mask = 256 / sizeof(half);
// repeatTime = 4, 128 elements one repeat, 512 elements total
// dstBlkStride, srcBlkStride = 1, no gap between blocks in one repeat
// dstRepStride, srcRepStride = 8, no gap between repeats
AscendC::Abs(dstLocal, srcLocal, mask, 4, { 1, 1, 8, 8 });

Result example:

Input (srcLocal): [0.0 -1.0 2.0 -3.0 ...]
Output data dstLocal: [0.0 1.0 2.0 3.0...]

Example of high-dimensional tensor sharding computation (bitwise mask mode), where both srcLocal and dstLocal are of the half type.

        
             uint64_t mask[2] = { UINT64_MAX, UINT64_MAX };
// repeatTime = 4, 128 elements one repeat, 512 elements total
// dstBlkStride, srcBlkStride = 1, no gap between blocks in one repeat
// dstRepStride, srcRepStride = 8, no gap between repeats
AscendC::Abs(dstLocal, srcLocal, mask, 4, { 1, 1, 8, 8 });

Result example:

Input (srcLocal): [0.0 -1.0 2.0 -3.0 ...]
Output data dstLocal: [0.0 1.0 2.0 3.0...]

API example of computing the first n data elements of a tensor, where both srcLocal and dstLocal are of the half type.

        
             AscendC::Abs(dstLocal, srcLocal, 512);

Result example:

Input (srcLocal): [0.0 -1.0 2.0 -3.0 ...]
Output data dstLocal: [0.0 1.0 2.0 3.0...]

Parent topic: Basic arithmetic operations