Function expm1

src/myFunc.cpp:2630–2635

#if defined(_WIN32) || (defined(__APPLE__) && defined(__MACH__))
double expm1(double x) {
        if (fabs(x) < 1e-5)
                return x + 0.5*x*x;
        else
                return exp(x) - 1.0;
}
double log1p(double x) {
        if (fabs(x) < 1e-5)
                return (x-x*x/2+x*x*x/3);