\item \verb+AVX2_256+ Yet more recent Intel x86 have this
\item \verb+IBM_QPX + BlueGene/Q A2 cores have this
\item \verb+Sparc64_HPC_ACE+ Fujitsu machines like the K computer have this
-\end{enumeration}
+\end{enumerate}
The \cmake{} configure system will check that the compiler you have
chosen can target the architecture you have chosen. mdrun will check
further at runtime, so if in doubt, choose the lowest setting you