acospi

接口定义

C interface：

float acospif(float x);

double acospi(double x);

参数

返回值

• 返回输入实数x的反余弦函数值除以π的值y=acos(x) / π，y ∈ [0, 1]。
• 输入±0，返回0.5。
• 输入x为1，返回+0。
• 输入x为-1，返回1。
• 输入|x|>1，返回nan。
• 输入±∞，返回nan。
• 输入±nan，返回±nan。

依赖

C: "km.h"

示例

C interface：

    // print result
    printf("acospi(0.0) = %.15f\n", acospi(0.0));
    printf("acospi(-0.0) = %.15f\n", acospi(-0.0));
    printf("acospi(0.25) = %.15f\n", acospi(0.25));
    printf("acospi(-0.25) = %.15f\n", acospi(-0.25));
    printf("acospi(0.5) = %.15f\n", acospi(0.5));
    printf("acospi(-0.5) = %.15f\n", acospi(-0.5));
    printf("acospi(1.0) = %.15f\n", acospi(1.0));
    printf("acospi(-1.0) = %.15f\n", acospi(-1.0));
    printf("acospi(INFINITY) = %.15f\n", acospi(INFINITY));
    printf("acospi(-INFINITY) = %.15f\n", acospi(-INFINITY));
    printf("acospi(NAN) = %.15f\n", acospi(NAN));
    printf("acospi(-NAN) = %.15f\n", acospi(-NAN));
    /* 
     * acospi(0.0) = 0.500000000000000
     * acospi(-0.0) = 0.500000000000000
     * acospi(0.25) = 0.419569376744834
     * acospi(-0.25) = 0.580430623255166
     * acospi(0.5) = 0.333333333333333
     * acospi(-0.5) = 0.666666666666667
     * acospi(1.0) = 0.000000000000000
     * acospi(-1.0) = 1.000000000000000
     * acospi(INFINITY) = nan
     * acospi(-INFINITY) = nan
     * acospi(NAN) = nan
     * acospi(-NAN) = -nan
     * 
     * */