rxdmath.cpp

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#include <math.h>
#ifndef M_PI
#define M_PI (3.14159265358979323846)
#endif

/*Some functions supported by numpy that aren't included in math.h
 * names and arguments match the wrappers used in rxdmath.py
 */

extern "C" double factorial(const double x)
{
    return tgamma(x+1.);
}


extern "C" double degrees(const double radians)
{
    return radians * (180. / M_PI);
}

extern "C" void radians(const double degrees, double *radians)
{
    *radians = degrees * (M_PI / 180.);
}


extern "C" double log1p(const double x)
{
    return log(x+1.);
}

extern "C" double vtrap(const double x, const double y)
{
    if(fabs(x/y) < 1e-6)
    {
        return y*(1.0 - x/y/2.0);
    }
    else
    {
        return x/(exp(x/y) - 1.0);
    }
}