hrsqrt

Applicability

Function Usage

Obtains the reciprocal of the square root of the input data x.

Prototype

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inline half hrsqrt(half x)

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inline bfloat16_t hrsqrt(bfloat16_t x)

Parameters

Returns

Reciprocal of the square root of the input data.

• If x is 0, the return value is inf.
• If x is inf, the return value is 0.
• If x is -inf, the return value is nan.
• If x is nan, the return value is nan.

Restrictions

The input data x supported by this API must be greater than or equal to 0. Otherwise, the return value is nan.

For SIMT programming, this API is not supported.

Header File to Be Included

To use the half API, the simt_api/asc_fp16.h header file must be included. To use the bfloat16_t API, the simt_api/asc_bf16.h header file must be included.

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#include "simt_api/asc_fp16.h"

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#include "simt_api/asc_bf16.h"

Examples

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__simt_vf__ __launch_bounds__(1024) inline void KernelRsqrt(__gm__ half* dst, __gm__ half* x)
{
    int idx = threadIdx.x + blockIdx.x * blockDim.x;
    dst[idx] = hrsqrt(x[idx]);
}