---
title: erfinv
description: "逆误差函数，输入参数为实数。"
url: https://www.hikunpeng.com/document/detail/zh/kunpenghpcs/hpckit/devg/kunpengaccel_kml_0223.html
sourcePath: /source/zh/kunpenghpcs/hpckit/devg/kunpengaccel_kml_0223.html
indexId: b4af0c451f1d20795d6581fb8f0e2b6f1b38906ddd6fceeaad8471c3b42de87661
---
# erfinv

逆误差函数，输入参数为实数。

#### 接口定义

C interface：

float erfinvf(float x);

double erfinv(double x);


#### 参数

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


#### 返回值

- 返回入参x的逆误差函数结果y，y ∈ [-inf, +inf]。
- 输入nan，返回nan。
- 输入+∞，返回nan。
- 输入-∞，返回nan。
- 输入1，返回+inf。
- 输入-1，返回-inf。
- 输入x > 1，返回nan。
- 输入x < -1，返回nan。


#### 依赖

C: "km.h"


#### 示例

C interface：```
// print result
    printf("erfinv(0.0) = %.15f\n",erfinv(0.0));
    printf("erfinv(-0.0) = %.15f\n",erfinv(-0.0));
    printf("erfinv(0.25) = %.15f\n",erfinv(0.25));
    printf("erfinv(-0.25) = %.15f\n",erfinv(-0.25));
    printf("erfinv(0.5) = %.15f\n",erfinv(0.5));
    printf("erfinv(-0.5) = %.15f\n",erfinv(-0.5));
    printf("erfinv(1.0) = %.15f\n",erfinv(1.0));
    printf("erfinv(-1.0) = %.15f\n",erfinv(-1.0));
    printf("erfinv(2.0) = %.15f\n",erfinv(2.0));
    printf("erfinv(-2.0) = %.15f\n",erfinv(-2.0));
    printf("erfinv(INFINITY) = %.15f\n",erfinv(INFINITY));
    printf("erfinv(-INFINITY) = %.15f\n",erfinv(-INFINITY));
    printf("erfinv(NAN) = %.15f\n",erfinv(NAN));
    printf("erfinv(-NAN) = %.15f\n",erfinv(-NAN));
    /* 
     * erfinv(0.0) = 0.000000000000000
     * erfinv(-0.0) = -0.000000000000000
     * erfinv(0.25) = 0.225312055012178
     * erfinv(-0.25) = -0.225312055012178
     * erfinv(0.5) = 0.476936276204470
     * erfinv(-0.5) = -0.476936276204470
     * erfinv(1.0) = inf
     * erfinv(-1.0) = -inf
     * erfinv(2.0) = nan
     * erfinv(-2.0) = nan
     * erfinv(INFINITY) = nan
     * erfinv(-INFINITY) = nan
     * erfinv(NAN) = nan
     * erfinv(-NAN) = -nan
     * 
     * */
```