return 0.0;
else if (x - _M_x0 > _M_lambda / 4)
return 0.0;
- else
- return std::cos(2 * M_PI * (x - _M_x0) / _M_lambda);
+ else {
+ const double pi = 3.1415926535897932384626433832795029L;
+ return std::cos(2 * pi * (x - _M_x0) / _M_lambda);
+ }
}
private: