Ruby Multi-dimensional Arrays

In Ruby standard library

• Matrix class (see document in lib/matrix.rb)

      require 'matrix'
      Matrix.I(3)
         #=> Matrix[[1, 0, 0], [0, 1, 0], [0, 0, 1]]
      Matrix[[0,1],[2,0]] * Vector[1.2,3.4]
         #=> Vector[3.4, 2.4]
  

Extension libraries

• MDArray
  Simple extension library for Multi-Dimensional Array. This library is targeted for old versions of Ruby. To compile with the current version, rename function names:

    mv mdarray.c mdarray.c.bak
    ruby (ruby_unpacked_dir)/sample/rename.rb mdarray.c.bak > mdarray.c
    ruby -r mkmf -e 'create_makefile("mdarray")'
    make
  

• NdimArray
  Ruby script version of Multi-dimensional Array

• Numerical Multi-dimensional Arrays (in RAA)
  
  • mathx
  • NArray
  • NumArray

In ML

• 50-by-50-element matrix with each one equal to "+"? (2001-05-01)
  

• Multidimensional arrays and hashes like Perl? (2001-04-01)
  Discussion on auto-vivification follows.

• Caution: Array.new fills with an *identical* object (2001-03-06)

      a = Array.new(2,Array.new(2)) #=> [[nil, nil], [nil, nil]]
      a[0][0] = 1
      p a                           #=> [[1, nil], [1, nil]]
  

• Resizable multi-dimensional Array (2001-02-25)

  case: 2-D

      class Array2D < Array
        def [](n)
           self[n]=Array.new if super(n)==nil
           super(n)
        end
      end
  
      a = Array2D.new
      a[2][2] = "foo"  #=> [nil, nil, [nil, nil, "foo"]]
  

  case: Multi-D

      class ArrayMD < Array
        def [](n)
           self[n]=ArrayMD.new if super(n)==nil
           super(n)
        end
      end
  
      a = ArrayMD.new
      a[1][2][3]="foo"  #=> [nil, [nil, nil, [nil, nil, nil, "foo"]]]
  

• Multi-dimensional array for games? (2001-02-04)
  A good example is (ruby_unpacked_dir)/sample/mine.rb, which is a simple mine sweeper game, although it uses Japanese characters.

• 3-D Array example (2000-06-08)