From: "Diego N." <lists@...>
Date: 2013-07-17T01:21:33+09:00
Subject: Re: Get part of matrix

First, thanks Carlos Agarie and Stefano Crocco for help me! :)

I decided to use the native Matrix class... but i needed to get square
around 54, for instance:

I'm trying to make a method:


  def build_matrix(r=0, c=0)
    m = Matrix.build(c, r) {|row, col| col + (row * r) }
  end

  def my_method(position, size)
    rows_size = 10
    cols_size = 10

    matrix  = build_matrix(rows_size, cols_size)
    area      = position - (Math.sqrt(size).to_i *
rows_size) - Math.sqrt(size).to_i
    return matrix.minor(matrix.index(area)[0],
size,matrix.index(area)[1], size)
  end

= my_method(54, 3)
-> Matrix[[43, 44, 45], [53, 54, 55], [63, 64, 65]]

= my_method(54, 3)
-> Matrix[[32, 33, 34, 35, 36], [42, 43, 44, 45, 46], [52, 53, 54, 55,
56], [62, 63, 64, 65, 66], [72, 73, 74, 75, 76]]

Where i pass 54(name of position) and 3(area of square).

It work! But, if i pass 40, for instance not work as well, because 40 is
on the corner...

Anyone knows if the matrix class can do this easier? get the square
around 54. 54 is my center..
On position 40, it should return ( 30, 31, 41, 50, 51)..

Thanks on more time!
Diego

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