Stdlib and Utilities

PythiaStdlib and PythiaComplex only exist as header files, collecting some simple declarations and inline utilities.

PythiaStdlib collects the include and using statements that are required by most other classes to access the C++ Stdlib containers and methods, such as string, vector, map, some mathematical functions, and input/output streams and formats. It defines M_PI if this is not already done.

There are also a few inlined functions: pow2(x), pow3(x), pow4(x) and pow5(x) for small integer powers, and sqrtpos(x) where a max(0., x) ensures that one does not take the square root of a negative number.

PythiaComplex defines a complex data type by a typedef std::complex<double>.