inline double create(double a, double b, double c, double w = 1.0)

inline double clip(double value)

const double required = ( 1000.0, 1000.0, 1000.0 )

const double strong = ( 1.0, 0.0, 0.0 )

const double medium = ( 0.0, 1.0, 0.0 )

const double weak = ( 0.0, 0.0, 1.0 )