Factorials

Ruby factorials as C extension.

Installation

Add this line to your application's Gemfile:

gem'factorials'

And then execute:

$ bundle

Or install it yourself as:

$ gem install factorials

Usage

Factorial

10.factorial# => 3628800

Double Factorial

10.double_factorial# => 3840

Super Factorial

5.superfactorial# => 34560

Benchmark

Conditions:

Benchmark.bmbm(7)do |x|
int=100_000x.report('Factorial (Ruby)')do(1..int).inject(:*)endx.report('Factorial (C)')doint.factorialendend

Results:

Rehearsal ----------------------------------------------------
Factorial (Ruby) 4.710000 2.320000 7.030000 ( 7.495018)
Factorial (C) 0.000000 0.000000 0.000000 ( 0.000156)
------------------------------------------- total: 7.030000sec
user system total real
Factorial (Ruby) 4.720000 2.400000 7.120000 ( 7.787638)
Factorial (C) 0.000000 0.000000 0.000000 ( 0.000131)

TODO

• Support very long long long integers.

Contributing

1. Fork it (https://github.com/droptheplot/factorials/fork)
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request

License

The gem is available as open source under the terms of the MIT License.