```aaron,

You should take a look at NMatrix: https://github.com/sciruby/nmatrix. It's
a numerical linear algebra library for Ruby built in C++. There is a sparse
storage type called "yale" which you can use:

require 'nmatrix'

values = [[5,0,3],[4,5,8],[7,8,9]]
matriz1 = NMatrix.new([3, 3], values, :stype => :yale)

And you should be good to go. If you have any trouble installing or
otherwise using NMatrix, please post on the issue tracker or on the mailing
list. :)

-----
Carlos Agarie
Software Engineer @ Geekie (geekie.com.br)
+55 11 97320-3878
@carlos_agarie

2013/11/17 aaron v. <lists / ruby-forum.com>

> Hi,
> Emerged me a doubt to perform some operations with dense matrices and
> sparse matrices.
> I'm doing a few methods to check whether an array is dense or not and
> use a hash of hashes, for then do methods of addition and subtraction
> between dense and sparse matrices.
> Will also have to wear the coerce to do the conversion in the matrix
> when performing the operation between the values of arrays.
> We have in this code that does the calculation.
> An example of sparse arrays in Ruby
>
> Thanks.
>
>
> matriz1 = ([[5,0,3],[4,5,8],[7,8,9]])
>                 hsh = Hash.new
>                 i=0
>                        while i < 3
>                        j=0
>                        while j < 3
>                             if (matriz1[i][j] != 0)
>                             puts  matriz1[i][j]
>                                 hsh["#{i}"] = Hash.new
>                                  hsh["#{i}"]["#{j}"] = matriz1[i][j]
>                  else
>                  end
>                  j += 1
>           end
>           i += 1
>       end
>  hsh.each {|key, value|
>
>     value.each{ |k, v|
>        puts key
>        puts k
>         puts v
>         puts "[#{key}, #{k}] = #{v}"}
> }
>
> --
> Posted via http://www.ruby-forum.com/.
>
```