Ruby Standard Deviation [reverted before it got yanked from rubygems]
This is a native extension to Ruby that adds a standard deviation calculation to the Array class.
Check the TravisCI build to see the currently supported versions of Ruby. This list will match whatever versions are specified at https://www.ruby-lang.org/en/downloads/.
It is much more performant than calculating the standard deviation with pure Ruby. For a comparison, run the benchmarks with rake.
bench_native_extension 0.000573 0.000507 0.000616 0.000606 0.000528
bench_pure_ruby 0.004794 0.004045 0.002673 0.002667 0.003728
Usage
require 'ruby-standard-deviation'
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
Links
This is the second version of this gem, and it is a total rewrite of a SWIG-based design. Lots of thanks to the following resources: