[scilab-Users] Re: Genetic Algoritm

[michael.baudin at contrib.scilab.org]

 Hi,

 On Thu, 19 Jul 2012 02:30:50 -0700 (PDT), rcbsimoes 
 <rcbsimoes at hotmail.com> wrote:
> ok, back again.
>
> i've used the continuous optimization which worked great!

 That's good to hear !

> 1)
> when you state binary length, here:
> BinLen = get_param(ga_params,'binary_length')
> is this the string length produced by the algorithm regardless of the
> dimension?
>
> for instance,
> if i have a 3 dimension problem which requires 2 bit lenght for each
> variable (x='01', y='00', z='11')
> should i set dimension as one, and 6 bits as string lenght?
> or should i set dimension to 3 and lenght to 2??

 This is dimension=3 and binlen=2.

> 2)
> [...]
>
> ? what is 'n' for ?


 "n" is an option of the "deff" function : function is not "compiled".
 This means that you can see the code more easily
 as opposed to a profiled function.


> *  [...]
> f(['11110000' '01010101'])
>  !--error 15
> Submatrix incorrectly defined.
>
> at line       5 of function convert_to_float called by :
>   = convert_to_float(x, BinLen, 1, -1);                y      = 
> rastrigin(tm
> at line       2 of function f called by :
> f(['11110000' '01010101'])

 The example you give has two errors:
  * The minimum and maximum bounds should be vectors which
    size corresponds to the dimension of the problem.
  * The argument is "1111000001010101" and not ['11110000' '01010101'].
    The algorithm works directly with the concatenation of
    two separate genes.

 Here is the example with works.

 function y = rastrigin(x)
   y = x(1)^2+x(2)^2-cos(12*x(1))-cos(18*x(2));
 endfunction

 function y=f(x)
   BinLen = 8
   tmp    = convert_to_float(x, BinLen, [1 1], [-1 -1])
   y      = rastrigin(tmp)
 endfunction

 y=f("1111000001010101")

 The previous script produces:
 -->y=f("1111000001010101")
  y  =
     0.3256550

 Here is an intermediate computation:
 -->convert_to_float("1111000001010101", 8, [1 1], [-1 -1])
  ans  =
     0.8823529
   - 0.3333333

 You may see the bug report :

 http://bugzilla.scilab.org/show_bug.cgi?id=7912

 for more details and examples.

 Best regards,

 Michaël