/* Copyright (C) 1994 DJ Delorie, see COPYING.DJ for details */ #include /* * @implemented */ double tanh(double x) { if (x > 50) return 1; else if (x < -50) return -1; else { const double ebig = exp(x); const double esmall = 1.0/ebig; return (ebig - esmall) / (ebig + esmall); } }