hypot

接口定义

C interface：

float hypotf(float x, float y);

double hypot(double x, double y);

long double hypotl(long double x, long double x);

参数

返回值

• 返回x^2 + y^2的平方根，x ∈ (-INF, +INF)，y ∈ (-INF, +INF)。
• 输入x为±inf或者y为±inf，返回inf。
• 输入x为nan或者y为nan，返回nan。
• x^2 + y^2开方大于inf，返回inf（Intel在部分情况会返回nan）。

依赖

C: "km.h"

示例

C interface：

    // typical usage
    float x1 = 3.0, x2 = 0x1.fp127;
    float y1 = 4.0, y2 = -0x1p70;
    // special handling
    float e = INFINITY, f = -INFINITY, g = NAN;
    // print result
    printf("hypotf(3.0, 4.0) = %.15f\n", hypotf(x1, y1));
    printf("hypotf(0x1.fp127, 0x1.fp127) = %.15f\n", hypotf(x2, x2));
    printf("hypotf(-0x1p70, -0x1p70) = %.15f\n", hypotf(y2, y2));
    printf("hypotf(INFINITY, 0) = %.15f\n", hypotf(e, 0.0f));
    printf("hypotf(-INFINITY, 3.0) = %.15f\n", hypotf(f, x1));
    printf("hypotf(NAN, 3.0) = %.15f\n", hypotf(g, x1));
    printf("hypotf(NAN, INFINITY) = %.15f\n", hypotf(g, e));
    /* 
     * hypotf(3.0, 4.0) = 5.000000000000000
     * hypotf(0x1.fp127, 0x1.fp127) = inf
     * hypotf(-0x1p70, -0x1p70) = 1669608653068460621824.000000000000000
     * hypotf(INFINITY, 0) = inf
     * hypotf(-INFINITY, 3.0) = inf
     * hypotf(NAN, 3.0) = nan
     * hypotf(NAN, INFINITY) = inf
     * 
     * */