---
title: powr
description: "计算x的y次幂，其中x≥0。"
url: https://www.hikunpeng.com/document/detail/zh/kunpengboostkithistory/240RC2/accel/kunpengaccel_kml_16_0381.html
sourcePath: /source/zh/kunpengboostkithistory/240RC2/accel/kunpengaccel_kml_16_0381.html
indexId: 236181132a995b07cb954405a6b4a1275a57829f9b0748a8cc0e04be6af3a61b76
---
# powr

计算x的y次幂，其中x≥0。

#### 接口定义

C interface：

float powrf(float x, float y);

double powr(double x, double y);


#### 参数

| 参数名 | 类型 | 描述 | 输入/输出 |
| --- | --- | --- | --- |
| x | 在powrf中，x是单精度浮点类型。 在powr中，x是双精度浮点类型。 | 表示输入数据的浮点值。 | 输入 |
| y | 在powrf中，y是单精度浮点类型。 在powr中，y是双精度浮点类型。 | 表示输入数据的浮点值。 | 输入 |


#### 返回值

- x大于等于0且y为正常值，返回幂指数的结果，取值范围(0, +INF)。
- x小于0，返回nan。
- 其他特殊值组合如下所示。| 输入值（x） | 输入值（y） | 输出值（result） |
| --- | --- | --- |
| +0 | +0 | +1 |
| +0 | \-0 | +1 |
| +0 | inf | +0 |
| +0 | \-inf | inf |
| +0 | snan | nan |
| +0 | \-snan | nan |
| +0 | qnan | nan |
| +0 | \-qnan | nan |
| \-0 | +0 | +1 |
| \-0 | \-0 | +1 |
| \-0 | inf | +0 |
| \-0 | \-inf | inf |
| \-0 | snan | nan |
| \-0 | \-snan | nan |
| \-0 | qnan | nan |
| \-0 | \-qnan | nan |
| inf | +0 | +1 |
| inf | \-0 | +1 |
| inf | inf | inf |
| inf | \-inf | +0 |
| inf | snan | nan |
| inf | \-snan | nan |
| inf | qnan | nan |
| inf | \-qnan | nan |
| \-inf | +0 | nan |
| \-inf | \-0 | nan |
| \-inf | inf | nan |
| \-inf | \-inf | nan |
| \-inf | snan | nan |
| \-inf | \-snan | nan |
| \-inf | qnan | nan |
| \-inf | \-qnan | nan |
| snan | +0 | +1 |
| snan | \-0 | +1 |
| snan | inf | nan |
| snan | \-inf | nan |
| snan | snan | nan |
| snan | \-snan | nan |
| snan | qnan | nan |
| snan | \-qnan | nan |
| \-snan | +0 | +1 |
| \-snan | \-0 | +1 |
| \-snan | inf | nan |
| \-snan | \-inf | nan |
| \-snan | snan | nan |
| \-snan | \-snan | nan |
| \-snan | qnan | nan |
| \-snan | \-qnan | nan |
| qnan | +0 | +1 |
| qnan | \-0 | +1 |
| qnan | inf | nan |
| qnan | \-inf | nan |
| qnan | snan | nan |
| qnan | \-snan | nan |
| qnan | qnan | nan |
| qnan | \-qnan | nan |
| \-qnan | +0 | +1 |
| \-qnan | \-0 | +1 |
| \-qnan | inf | nan |
| \-qnan | \-inf | nan |
| \-qnan | snan | nan |
| \-qnan | \-snan | nan |
| \-qnan | qnan | nan |
| \-qnan | \-qnan | nan |


#### 依赖

C: "km.h"


#### 示例

C interface：

```
// typical usage
double x1 = 0.0, x2 = -0.0, x3 = 1.5, x4 = -2.5;
// special handing
double a = INFINITY, b = -INFINITY, c = NAN;
// print result
printf("powr(0.0, -0.0) = %.15f\n", powr(x1, x2));
printf("powr(-0.0, 0.0) = %.15f\n", powr(x2, x1));
printf("powr(1.5, 1.5) = %.15f\n", powr(x3, x3));
printf("powr(-2.5, 1.5) = %.15f\n", powr(x4, x3));
printf("powr(INFINITY, 1.5) = %.15f\n", powr(a, x3));
printf("powr(-INFINITY, 1.5) = %.15f\n", powr(b, x3));
printf("powr(NAN, NAN) = %.15f\n", powr(c, c));
return 0;
/*
* powr(0.0, -0.0) = 1.000000000000000
* powr(-0.0, 0.0) = 1.000000000000000
* powr(1.5, 1.5) = 1.837117307087384
* powr(-2.5, 1.5) = nan
* powr(INFINITY, 1.5) = inf
* powr(-INFINITY, 1.5) = nan
* powr(NAN, NAN) = nan
*/
```