This is a native extension to Ruby that adds native (Rust) statistical functions to the Array class. At present the following functions are provided:
- Sample Standard Deviation (stdev, stdevs)
- Population Standard Deviation (stdevp)
- Sample Variance (var)
- Population Variance (varp)
- Median (median)
- Mean (mean)
- Percentile (percentile)
Check the Github Actions build to see the currently supported versions of Ruby. This list will match whatever stable versions are specified at https://www.ruby-lang.org/en/downloads/.
It is generally more performant than calculating these values with pure Ruby. For a comparison, run the benchmarks with rake benchmark.
Here's the data converted to a Markdown table:
| Benchmark (Ruby 3.4.4) | Run 1 | Run 2 | Run 3 | Run 4 | Run 5 |
|---|---|---|---|---|---|
| bench_ruby_median | 0.000676 | 0.000611 | 0.000619 | 0.000620 | 0.000583 |
| bench_native_median | 0.000179 | 0.000167 | 0.000127 | 0.000118 | 0.000188 |
| bench_ruby_stdev | 0.000780 | 0.000767 | 0.000730 | 0.000718 | 0.000733 |
| bench_native_stdev | 0.000046 | 0.000027 | 0.000034 | 0.000026 | 0.000043 |
| bench_ruby_mean | 0.000261 | 0.000240 | 0.000242 | 0.000250 | 0.000241 |
| bench_native_mean | 0.000033 | 0.000023 | 0.000022 | 0.000028 | 0.000022 |
If you found a bug or need a particular function, please let me know! I work on this gem in my spare time, mainly for learning purposes. Feel free to open a PR or a Github issue and I'll take a look as soon as possible.
require 'ruby_native_statistics'
r = [1,3,21,32,42]
# calculate sample standard deviation, you can also use "stdevs"
p r.stdev
# calculate population standard deviation
p r.stdevp
# calculate sample variance
p r.var
# calculate population variance
p r.varp
# calculate mean
p r.mean
# calculate median
p r.median
# calculate percentile
p r.percentile(0.3333)
If you are installing the source vesion of the Gem, be sure to have libclang, e.g. libclang-dev, installed on your system.
Percentile uses the same rounding method as Excel, sometimes called R7.