From: Todd Benson <caduceass@...>
Date: 2008-08-18T08:23:41+09:00
Subject: Re: Matrix: Need help to understand this behavior

On Sun, Aug 17, 2008 at 9:53 AM, Marcio Braga <mbraga0001@gmail.com> wrote:
> Zacek and all: how to duplicate a matrix that has elements that are also
> matrix ?
> For example:
>
> a = [[1]]
> b = a.dup
> puts a.object_id
> puts b.object_id
> puts a[0].object_id   # the same object
> puts b[0].object_id   # the same object
> b[0][0] = 2 * b[0][0]
> p a
> p b
>
> So, matrix "a" and "b" are different objects but each internal matrix
> element continue to be the same object. Do I need to duplicate each one
> ?

It's a Matrix, right? (some of this stolen from a previous thread)...

require 'matrix'
class Matrix
  def []=(i, j, n)
    @rows[i][j] = n
  end
end

m = Matrix[['a', 'b'], ['c', 'd']]
k = m.clone
k[0, 0] = 'e'
puts k.to_a
puts m.to_a

Todd