\left|\left(\left(\tan^{-1}_* \frac{\mathsf{expm1}\left(\left(\sin \left(\mathsf{expm1}\left(a\right)\right)\right)\right)}{\tan^{-1} a}\right) \bmod a\right)\right|double f(double a) {
double r8005 = a;
double r8006 = expm1(r8005);
double r8007 = sin(r8006);
double r8008 = expm1(r8007);
double r8009 = atan(r8005);
double r8010 = atan2(r8008, r8009);
double r8011 = fmod(r8010, r8005);
double r8012 = fabs(r8011);
return r8012;
}