mutation operators
2-op (swap of 2 elements)  location specific. changes 2 vertices

inversion               adjacent representations (edge). changes 2 edges
1 2 3 4 5 6
 |       |
1 5 4 3 2 6

1 - insertion               adjacent representations
1 2 3 4 5 6
  ^     v    
1 3 4 5 2 6

k-insertion         adj
k-op                loc




void shuffle(char *x, int elementcount)
{
    int k;

    // loop through selecting the element to place at location i
    for (int i=elementcount-1; i; i--) {
	int tmp;

	k=randMod(i+1);  // k can equal i
	tmp = x[i];
	x[i] = x[k];
	x[k] = tmp;
    }
}


=============================================================================
Evolution Strategies

chromosome: vector of reals
alleles are real numbers
parameters of search evolve



LOCAL SEARCH in Reals^N

       init X=(a_1, a_2, ...a_N)
       while (not good enough) {
           X' = X + (N(0, sigma), N(0, sigma), N(0, sigma),... N(0, sigma))
           if (fit(X') > fit(X)) X=X'
       }


SELF ADAPTING LOCAL SEARCH in Reals^N

       sigma = good starting value
       init X=(a_1, a_2, ...a_N)
       while (not good enough) {
           success=0
           repeat k times {
               X' = X + (N(0, sigma_1), N(0, sigma_2),... N(0, sigma_N))
               if (fit(X') > fit(X)) {
                   X=X'
                   success++
               }
           }
           if (success/k < 1/5) sigma *= c
           if (success/k > 1/5) sigma /= c
       }

1/5 rule - "rule of thumb" for how much success you want