Frac

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

x

Atlas inference product's AI Core

Atlas inference product's Vector Core

x

Atlas training products

x

Function

Returns decimals element-wise. The formula is as follows:

Examples:

Frac(-258.41888) = -0.41888428

Frac(5592.625) = 0.625

Prototype

  • Allocate the temporary space through the API framework.
    • All source operand tensors are involved in computation.
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      template <typename T, bool isReuseSource = false>
      __aicore__ inline void Frac(const LocalTensor<T>& dstTensor, const LocalTensor<T>& srcTensor)
      
    • All or part of the source operand tensors are involved in computation.
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      template <typename T, bool isReuseSource = false>
      __aicore__ inline void Frac(const LocalTensor<T>& dstTensor, const LocalTensor<T>& srcTensor, const uint32_t calCount)
      
  • Pass the temporary space through the sharedTmpBuffer input parameter.
    • All source operand tensors are involved in computation.
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      template <typename T, bool isReuseSource = false>
      __aicore__ inline void Frac(const LocalTensor<T>& dstTensor, const LocalTensor<T>& srcTensor, const LocalTensor<uint8_t>& sharedTmpBuffer)
      
    • All or part of the source operand tensors are involved in computation.
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      template <typename T, bool isReuseSource = false>
      __aicore__ inline void Frac(const LocalTensor<T>& dstTensor, const LocalTensor<T>& srcTensor, const LocalTensor<uint8_t>& sharedTmpBuffer, const uint32_t calCount)
      

Due to the complex mathematical computation involved in the internal implementation of this API, additional temporary space is required to store intermediate variables generated during computation. The temporary space can be passed by developers through the sharedTmpBuffer input parameter or allocated through the API framework.

  • When the API framework is used for temporary space allocation, developers do not need to allocate the space, but must reserve the required size for the space.
  • When the sharedTmpBuffer input parameter is used for passing the temporary space, the tensor serves as the temporary space. In this case, the API framework is not required for temporary space allocation. This enables developers to manage the sharedTmpBuffer space and reuse the buffer after calling the API, so that the buffer is not repeatedly allocated and deallocated, improving the flexibility and buffer utilization.

If the API framework is used, developers must reserve the temporary space. If sharedTmpBuffer is used, developers must allocate space for the tensor. To obtain the size of the temporary space (BufferSize) to be reserved, use the GetFracMaxMinTmpSize API provided in GetFracMaxMinTmpSize.

Parameters

Table 1 Template parameters

Parameter

Description

T

Data type of the operand.

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.

For the Atlas inference product's AI Core, the supported data types are half and float.

isReuseSource

Whether the source operand can be modified. This parameter is reserved. Pass the default value false.

Table 2 API parameters

Parameter

Input/Output

Description

dstTensor

Output

Destination operand.

The type is LocalTensor, and the supported TPosition is VECIN, VECCALC, or VECOUT.

srcTensor

Input

Source operand.

The type is LocalTensor, and the supported TPosition is VECIN, VECCALC, or VECOUT.

The source operand must have the same data type as the destination operand.

sharedTmpBuffer

Input

Temporary buffer.

The type is LocalTensor, and the supported TPosition is VECIN, VECCALC, or VECOUT.

This parameter is used to store intermediate variables during complex computation in Frac and is provided by developers.

For details about how to obtain the temporary space size (BufferSize), see GetFracMaxMinTmpSize.

calCount

Input

Number of elements involved in the computation.

Returns

None

Restrictions

  • For the Atlas inference product's AI Core, the input data must be within the range of [–2147483647.0, 2147483647.0].
  • The source operand address must not overlap the destination operand address.
  • For details about the operand address alignment requirements, see General Address Alignment Restrictions.

Example

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#include "kernel_operator.h"
template <typename srcType>
class KernelFrac
{
public:
    __aicore__ inline KernelFrac(){}
    __aicore__ inline void Init(GM_ADDR srcGm, GM_ADDR dstGm, uint32_t srcSize)
    {
        srcGlobal.SetGlobalBuffer(reinterpret_cast<__gm__ srcType *>(srcGm), srcSize);
        dstGlobal.SetGlobalBuffer(reinterpret_cast<__gm__ srcType *>(dstGm), srcSize);

        pipe.InitBuffer(inQueueX, 1, srcSize * sizeof(srcType));
        pipe.InitBuffer(outQueue, 1, srcSize * sizeof(srcType));
        bufferSize = srcSize;
    }
    __aicore__ inline void Process()
    {
        CopyIn();
        Compute();
        CopyOut();
    }

private:
    __aicore__ inline void CopyIn()
    {
        AscendC::LocalTensor<srcType> srcLocal = inQueueX.AllocTensor<srcType>();
        AscendC::DataCopy(srcLocal, srcGlobal, bufferSize);
        inQueueX.EnQue(srcLocal);
    }
    __aicore__ inline void Compute()
    {
        AscendC::LocalTensor<srcType> dstLocal = outQueue.AllocTensor<srcType>();
        AscendC::LocalTensor<srcType> srcLocal = inQueueX.DeQue<srcType>();
        AscendC::Frac<srcType, false>(dstLocal, srcLocal);
        outQueue.EnQue<srcType>(dstLocal);
        inQueueX.FreeTensor(srcLocal);
    }
    __aicore__ inline void CopyOut()
    {
        AscendC::LocalTensor<srcType> dstLocal = outQueue.DeQue<srcType>();
        AscendC::DataCopy(dstGlobal, dstLocal, bufferSize);
        outQueue.FreeTensor(dstLocal);
    }

private:
    AscendC::GlobalTensor<srcType> srcGlobal;
    AscendC::GlobalTensor<srcType> dstGlobal;

    AscendC::TPipe pipe;
    AscendC::TQue<AscendC::TPosition::VECIN, 1> inQueueX;
    AscendC::TQue<AscendC::TPosition::VECOUT, 1> outQueue;
    uint32_t bufferSize = 0;
};

template <typename dataType>
__aicore__ void kernel_frac_operator(GM_ADDR srcGm, GM_ADDR dstGm, uint32_t srcSize)
{
    KernelFrac<dataType> op;
    op.Init(srcGm, dstGm, srcSize);
    op.Process();
}

extern "C" __global__ __aicore__ void kernel_frac_operator(GM_ADDR srcGm, GM_ADDR dstGm, uint32_t srcSize)
{
    kernel_frac_operator<half>(srcGm, dstGm, srcSize);
}
Result example:
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Input data (srcLocal): [-258.41888  5592.625  -5312.416 ...  9423.014 -8336.825]
Output data (dstLocal): [-0.41888428 0.625  -0.41601562 ...  0.013671875 -0.8251953]