tanh implementations

mytanh.c

// James William Fletcher (github.com/mrbid) (June 2022)
#include <stdio.h>
#include <math.h>

static inline float mycosh(float f)
{
    return (powf(2.718281746F, f)*0.5f) + (powf(2.718281746F, -f)*0.5f);
}

static inline float mysinh(float f)
{
    return 0.5f * (powf(2.718281746F, f) - powf(2.718281746F, -f));
}

static inline float mytanh1(float f)
{
    return mysinh(f) / mycosh(f);
}

static inline float mytanh2(const float x)
{
    return ((expf(x) - expf(-x))/(expf(x) + expf(-x)));
}

static inline float mytanh3(float f)
{
    const float pe = powf(7.389056206F, f);
    return (pe-1.f) / (pe+1.f);
}

int main()
{
    printf("mycosh():  %.9f\n",   mycosh(0.2f));
    printf("coshf():   %.9f\n\n", coshf(0.2f));
    printf("mysinh():  %.9f\n",   mysinh(0.2f));
    printf("sinhf():   %.9f\n\n", sinhf(0.2f));
    printf("tanhf():   %.9f\n",   tanhf(0.2f));
    printf("mytanh1(): %.9f\n",   mytanh1(0.2f));
    printf("mytanh2(): %.9f\n",   mytanh2(0.2f));
    printf("mytanh3(): %.9f\n",   mytanh3(0.2f));
    return 0;
}

/*
    mycosh():  1.020066738
    coshf():   1.020066738

    mysinh():  0.201335996
    sinhf():   0.201336011

    tanhf():   0.197375327
    mytanh1(): 0.197375312
    mytanh2(): 0.197375312
    mytanh3(): 0.197375342
*/