# Re: Premature Optimization

**URL:** <https://www.ruby-forum.com/t/re-premature-optimization/73650>\
**Category:** Ruby\
**Created:** [October 25, 2006, 11:16pm UTC](https://www.ruby-forum.com/t/re-premature-optimization/73650 "2006-10-25T23:16:48Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![phrogz](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/2acd7d/32.png) [@phrogz](https://www.ruby-forum.com/u/phrogz)\
**Post date:** [October 25, 2006, 11:16pm UTC](https://www.ruby-forum.com/t/re-premature-optimization/73650/1 "2006-10-25T23:16:48Z")

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From: removed\_email\_address@domain.invalid [[mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)]

> first = [1,0,0,0,0]  
> second = [1,1,0,0,0]  
> third = [0,0,0,1,0]
> 
> I would end up with  
> count = [2,1,0,1,0]

Built into Ruby:  
irb(main):001:0\> require ‘matrix’  
=\> true  
irb(main):002:0\> first = Vector[1,0,0,0,0]  
=\> Vector[1, 0, 0, 0, 0]  
irb(main):003:0\> second = Vector[1,1,0,0,0]  
=\> Vector[1, 1, 0, 0, 0]  
irb(main):004:0\> third = Vector[0,0,0,1,0]  
=\> Vector[0, 0, 0, 1, 0]  
irb(main):005:0\> count = first + second + third  
=\> Vector[2, 1, 0, 1, 0]

However, I believe that’s a pure-ruby implementation of matrices and  
vectors. A quick bit of Googling looks ike RNum[1] might be crazy fast  
and do what you need. I’ve never used it. I’ve also never used  
NArray[2], but it might do what you need.

[1] [http://rnum.rubyforge.org/](http://rnum.rubyforge.org/)  
[2] [http://narray.rubyforge.org/](http://narray.rubyforge.org/)