I wouldn’t give much weight to those benchmark numbers at this point. Some of those language versions are quite out of date...
crb-omp 0m22.949s
crb 0m23.240s
crb_opt 0m31.404s
nimrb_pmap 0m8.828s
nimrb_fn 0m22.988s
nimrb 0m26.556s
The base C code is faster than base Nim code. The optimised C code is significantly slower than everything else(!?). The Nim program that uses a threadpool is the fastest of these.I couldn't get the CPP versions to compile. I'll do the Rust programs some other time.
If you fix that, on my machine it's 17.3 seconds for the base C version and 13.4 for the optimized one, i.e., a 22% improvement from turning on the extra optimizations (-march=native and -ffast-math).
And for whatever it's worth, because some people love hating on GCC in favor of Clang, my Clang timings are 19.5 and 16.5 seconds, respectively.