سورس کد هشت وزیر با fitness sharing
			 
			 
			
		
		
		
			
			سلام دوستان خسته نباشید  
من دونبال سورس هشت وزیر هستم که به جای یک جواب چند جواب بهینه بهمون بده یعنی فیتنس همه انها صفر باشه  
باید قسمت فیتنس توسط  
9.4.1 Fitness Sharing 
This scheme is based upon the idea that the number of individuals within a 
given niche is controlled by "sharing" their fitness immediately prior to selection. 
In practice the scheme works by considering each possible pairing of 
individuals i and j within the population (including i with itself) and calculating 
a distance d(i,j) between them according to some distance metric 
(phenotypic is preferred if possible, else genotypic, e.g., Hamming distance for 
binary representations). The fitness F of each individual i is then adjusted according 
to the number of individuals falling within some prespecified distance 
(J"share using a power-law distribution: 
I . F( i) 
F (z) = Lj sh(d(i,j)) ' 
where the sharing function sh(d) is a function of the distance d given by 
sh(d) = { 1 - (d/~share)a if d :::; (J"share, 
otherwise. 
As can be seen the constant value 0: determines the shape of the sharing 
function: for 0:=1 the function is linear, but for values greater than this the 
effect of similar individuals in reducing a solution's fitness falls off more rapidly 
with distance. 
The other parameter that needs to be set, and the one that decides both 
how many niches can be maintained and the granularity with which different 
niches can be discriminated, is the share radius (J"share. Deb [108] gives some 
suggestions for how this might be set if the number of niches is known in 
advance, but clearly this is not always the case. In [106] he suggests that a 
default value in the range 5-10 should be used. 
Finally, we should point out that the use of fitness proportionate selection is 
implicit within the fitness-sharing method. Studies have indicated that the use 
of alternative selection methods does not lead to the formation and preservation 
of stable subpopulations in niches [294]. However, if fitness proportionate 
selection is used, then there exists a stable distribution of solutions amongst 
the niches when solutions from each peak have the same effective fitness F'. 
This means that in each niche k the number of solutions present nk is proportional 
to the niche fitness Fk , so that F£ = Fk/nk is constant and equal 
for all niches2 . This point is illustrated in Fig. 9.2. 
 
 
درست بشه 
با الگوریتم ژنتیک نوشته بشه
		 
		
		
		
		
		
		
		
	 |