#ifndef BLACKB_H
#define BLACKB_H

/**
* This function returns the Debye-function of order 3
* of its argument x.
* The Debye-function of order n of x is defined as
*   (integral from 0 to x) of (t to the nth)/exp(t)-1) ) dt
* If the argument is less than zero, -1 is returned.
* The kernel of the integral is related to Plank's Radiation Function.
* (Literature: M. Abramowitz, I.A. Stegun, handbook of mathematical functions,
* Dover Publications, chapters 27.1.1, 23.2.16, Table 23.3
* @since 1990-09-28
* @author Richard J. Mathar
*/
class BlackB {
public:
	double T ;

	// ctor: Kelvin
	BlackB(double temp) ;

	double densitlam(const double lambda) const ;

	double densitnu(const double nu) const ;

	double fluxnu(const double nu[2], const bool argis_freq) const ;

	double fluxnuRel(const double nu[2], const double nuRef[2]) const ;

	double moment(const double nu[2], const bool argis_freq, const int n) const ;

protected:
private:
	double debye3(const double x) const ;

	double debyen(const double x, const int n) const ;
} ;
#endif /* BLACKB_H */