From: aix aix <ruby.aix@...>
Date: 2011-05-13T21:25:53+09:00
Subject: Calcul XOR : array , times.

Hello ,

I have problems with my code for XOR calcul :

    a = [1, 0, 1, 1, 0, 0, 1]
    b = ["101101", "101100", "110011", "000111", "010110"]
    # good result : 000001, 011010,101000, 001010,110000
    # false result : ["000001", "000000", "011111", "101011", "111010"]
=> output with this code
    # Why ? Because he spends that time with respect b[i].lenght ( = 6
generally ) that prevents take in this case the element 7 and 8 of "a".
    # works in case a.length <b [x]. length
    # How to resolv this problem ?
    i = j = x = 0
    c = []
    d = []
    f = []
    5.times { |x| c.push b[x].split('') }

    5.times { |i|
            e = c[i].length
            e.times { |j| d.push(a[j % 7].to_i ^ c[i][j].to_i) }
            f.push d
            d = []
    }
    puts "Résultat brute: "
    p f

    z = f.length
    z.times { |h| f[h] = f[h].join("")}

    puts "Résultats :"
    p f



In this case :

    a = [1, 0, 1, 1, 0, 0, 1]
    b = ["101101", "101100", "110011", "000111", "010110"]

After splitting

    b : [["1","0","1","1","0","1"], ["1","0","1","1","0","0"],
["1","1","0","0","1","1"],
     ["0","0","0","1","1","1"], ["0","1","0","1","1","0"]]

But `a.length => 7` and `b[x].length =>6`

In this code, the xor calcul is performed with only 6 elements in a on
7.

So the calculation is performed here:

    a[0] ^ b[0][0] ; a[1] ^ b[0][1] ; a[2] ^ b[0][2] ; a[3] ^ b[0][3] ;
a[4] ^ b[0][4] ; a[5] ^ b[0][5] ;
    a[0] ^ b[1][0] ; a[1] ^ b[1][1] ; a[2] ^ b[1][2] ; a[3] ^ b[1][3] ;
a[4] ^ b[1][4] ; a[5] ^ b[1][5] ;
    a[0] ^ b[2][0] ; a[1] ^ b[2][1] ; a[2] ^ b[2][2] ; a[3] ^ b[2][3] ;
a[4] ^ b[2][4] ; a[5] ^ b[2][5] ;
    a[0] ^ b[3][0] ; a[1] ^ b[3][1] ; a[2] ^ b[3][2] ; a[3] ^ b[3][3] ;
a[4] ^ b[3][4] ; a[5] ^ b[3][5] ;
    a[0] ^ b[4][0] ; a[1] ^ b[4][1] ; a[2] ^ b[4][2] ; a[3] ^ b[4][3] ;
a[4] ^ b[4][4] ; a[5] ^ b[4][5] ;

`a[6]` is never use.

and the calculation should be done:

    a[0] ^ b[0][0] ; a[1] ^ b[0][1] ; a[2] ^ b[0][2] ; a[3] ^ b[0][3] ;
a[4] ^ b[0][4] ; a[5] ^ b[0][5] ;
    a[6] ^ b[1][0] ; a[0] ^ b[1][1] ; a[1] ^ b[1][2] ; a[2] ^ b[1][3] ;
a[3] ^ b[1][4] ; a[4] ^ b[1][5] ;
    a[5] ^ b[2][0] ; a[6] ^ b[2][1] ; a[0] ^ b[2][2] ; a[1] ^ b[2][3] ;
a[2] ^ b[2][4] ; a[3] ^ b[2][5] ;
    a[4] ^ b[3][0] ; a[5] ^ b[3][1] ; a[6] ^ b[3][2] ; a[0] ^ b[3][3] ;
a[1] ^ b[3][4] ; a[2] ^ b[3][5] ;
    a[3] ^ b[4][0] ; a[4] ^ b[4][1] ; a[5] ^ b[4][2] ; a[6] ^ b[4][3] ;
a[0] ^ b[4][4] ; a[1] ^ b[4][5] ;

I want to make the right calculation of course but I do not see how to
this.

How to use a[6] as above ?

Thanks

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