double humps_antideriv ( double x );
double humps_deriv ( double x );
double humps_deriv2 ( double x );
double humps_fun ( double x );
double humps_ode ( double x, double y );
void plot_xy ( int n, double x[], double y[], string prefix );
double r8_square ( double x );
string s_escape_tex ( string s1 );
void timestamp ( );