safeeft
Safe and branchless error-free transformation algorithms for floating point numbers.
Now supports types which impl num_traits::Float and size of bits of its significand is odd (Because Float does not offer its size).
Benchmark
With nightly compiler, execute
$ cargo +nightly bench
If your CPU has fma target-feature,
$ RUSTFLAGS='-C target-cpu=native' cargo +nightly bench --features use-fma
If your CPU does not have fma and compile and run with this command, ***_fma will work very slowly due to software emulation of fma.
Sample result
- compiler: rustc 1.23.0-nightly
- CPU: Intel Core i5-4570(Haswell)@3.20GHz
twosum
| algorithm | time (ns) / operation |
|---|---|
twosum(not safe) |
1.7530 |
safetwosum_branch |
4.4827 |
safetwosum_straight |
4.6438 |
safetwosum_fma |
2.4749 |
split
| algorithm | time (ns) / operation |
|---|---|
split(not safe) |
0.8915 |
safesplit_branch(not safe) |
1.1918 |
safesplit_straight |
3.3454 |
twoproduct
| algorithm | time (ns) / operation |
|---|---|
twoproduct(not safe) |
2.9322 |
safetwoproduct_branch |
3.7826 |
safetwoproduct_straight |
12.9883 |
safetwoproduct_fma |
0.7125 |