# bloom filters

> This is an educational implementation for bloom filters and is meant to be low LOC

- The api is inspired a bit from the [Guava impl](https://github.com/google/guava/blob/master/guava/src/com/google/common/hash/BloomFilter.java#L99)
- For hashes it uses xxhash - the specific implementations shared [here](https://create.stephan-brumme.com/xxhash/#sourcecode)

Other than that the overall implementation itself is very short owing to the fact that this
works on byte chunks directly instead of understanding specific types ( and hence having handling 
for it which some libraries do )

Correctness I've verified via plots.

### Plots

![False positive rate vs k](plots/png/fpp_vs_k.png)
![False positive rate vs n](plots/png/fpp_vs_n.png)
![False positive rate vs m](plots/png/fpp_vs_m.png)

To regenerate:

```sh
cmake --build build
./build/bloom_filter_stats_csv plots/data/cases.csv > plots/data/bloom_filter_stats.csv
gnuplot plots/gnuplot/fpp_vs_k.gp
gnuplot plots/gnuplot/fpp_vs_n.gp
gnuplot plots/gnuplot/fpp_vs_m.gp
```

# Todo

- perf benchmarks
- modern variations added