I looked at the k-nucleotide, n-body, etc and saw nothing out of the ordinary in terms of C#.
There wasn’t even a lot of “modern C#” low level optimization like ref-structs/spans and similar. It actually looks like there is quite a bit of performance from C#8, 9, 10 left on the table.
// prevent inlining into main to decrease JIT time to generate main
[SkipLocalsInit][MethodImpl(NoInlining)]
[SkipLocalsInit][StructLayout(LayoutKind.Explicit, Pack = 32)]
[SkipLocalsInit][MethodImpl(AggressiveOptimization | NoInlining)]
[FieldOffset(32)]
and tons of "unchecked" blocks.
Not to mention that the entire file is using explicit vectorization, which I consider to be a very high degree of optimization -- tons of software never bothers to implement explicit vectorization, and does just fine.
If all of this is "nothing out of the ordinary", then "ordinary" C# has changed a lot since I last spent much time with it.
Agree - those attributes are definitely “low level” and not idiomatic in most situations. I must have missed them skimming that file.
For the particular case of n-body you could argue you are already in a pretty extreme HPC world and doing it without vectors would basically be a toy calculator. The problem then of course that C# isn’t really ever idiomatic for that. The question (as alaways) becomes about what to compare. Typical or pushed to the limit.
There wasn’t even a lot of “modern C#” low level optimization like ref-structs/spans and similar. It actually looks like there is quite a bit of performance from C#8, 9, 10 left on the table.