Notes for AXPBY

1. Performs $y \leftarrow \alpha x + \beta y$
2. An index file input line looks like:

   <ID> <alpha> <beta> <incX> <incY> <source file> <author name>
   

3. The kernel will never be called with beta == 1.0 (AXPY is called instead).
4. The kernel will never be called with beta == 0.0 (CPSC is called instead).
5. The kernel will never be called with alpha == 0.0 (SCAL is called instead).
6. For complex, if both vector strides are 1, and the imaginary components of alpha and beta are both zero, the real kernel is called with 2*N.