Sigmoid

Applicability

Function Usage

Performs element-wise logistic regression with Sigmoid using the following formula:

Prototype

• Pass the temporary space through the sharedTmpBuffer input parameter.
  • All or part of the source operand tensors are involved in computation.

    1 2	template <typename T, bool isReuseSource = false> __aicore__ inline void Sigmoid(const LocalTensor<T>& dstTensor, const LocalTensor<T>& srcTensor, const LocalTensor<uint8_t>& sharedTmpBuffer, const uint32_t calCount)

  • All source operand tensors are involved in computation.

    1 2	template <typename T, bool isReuseSource = false> __aicore__ inline void Sigmoid(const LocalTensor<T>& dstTensor, const LocalTensor<T>& srcTensor, const LocalTensor<uint8_t>& sharedTmpBuffer)

• Allocate the temporary space through the API framework.
  • All or part of the source operand tensors are involved in computation.

    1 2	template <typename T, bool isReuseSource = false> __aicore__ inline void Sigmoid(const LocalTensor<T>& dstTensor, const LocalTensor<T>& srcTensor, const uint32_t calCount)

  • All source operand tensors are involved in computation.

    1 2	template <typename T, bool isReuseSource = false> __aicore__ inline void Sigmoid(const LocalTensor<T>& dstTensor, const LocalTensor<T>& srcTensor)

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

• 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 temporary 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 or 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 sharedTmpBuffer. To obtain the size of the temporary space (BufferSize) to be reserved, use the API provided in GetSigmoidMaxMinTmpSize.

Parameters

Returns

None

Constraints

• For details about the operand address alignment requirements, see General Address Alignment Restrictions.

• The source operand address must not overlap the destination operand address.
• The address of sharedTmpBuffer cannot overlap that of the source or destination operand.

Examples

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// dstLocal: tensor for storing the Sigmoid computation result
// srcLocal: tensor for storing the Sigmoid computation input
// sharedTmpBuffer: tensor for storing the temporary buffer during Sigmoid computation

// Allocate the temporary space through the API framework, all of which is used for computation.
AscendC::Sigmoid(dstLocal, srcLocal);
// Allocate the temporary space through the API framework, part of which is used for computation, with the number of elements involved in the computation being 32.
AscendC::Sigmoid(dstLocal, srcLocal, 32);

// Pass the temporary space through the sharedTmpBuffer input parameter, all of which is used for computation.
AscendC::Sigmoid(dstLocal, srcLocal, sharedTmpBuffer);
// Pass the temporary space through the sharedTmpBuffer input parameter, part of which is used for computation, with the number of elements involved in computation being 32.
AscendC::Sigmoid(dstLocal, srcLocal, sharedTmpBuffer, 32);

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Input (srcLocal):
[-100.    -50.    -20.    -10.     -5.     -4.     -3.     -2.
   -1.     -0.5    -0.4    -0.3    -0.2    -0.1    -0.01    0.
    0.      0.01    0.1     0.2     0.3     0.4     0.5     1.
    2.      3.      4.      5.     10.     20.     50.    100.  ]
Output (dstLocal):
[0.         0.         0.         0.0000454  0.00669285 0.01798621 0.04742587 0.11920292
 0.26894142 0.37754067 0.40131234 0.42555748 0.450166   0.47502081 0.49750002 0.5
 0.5        0.50249998 0.52497919 0.549834   0.57444252 0.59868766 0.62245933 0.73105858
 0.88079708 0.95257413 0.98201379 0.99330715 0.9999546  1.         1.         1.        ]