//	x = v; //ambiguity in std::complex::operator=

struct cdouble : std::complex<double>
{
	typedef std::complex<double> C;
	cdouble() {}
	cdouble(double r) : C(r) {}
	cdouble(double r, double i) : C(r,i) {}
	cdouble(const Nuller&) { operator=(DOUBLE_NULL); }
};