《模拟退火(SA)求解0-1背包问题》

a = 0.95;
weight = [2;5;18;3;2;5;10;4;11;7;14;6];
value = [5;10;13;4;3;11;13;10;8;16;7;4];
value = -value;
restriction = 46;
num = 12;

newSol = ones(1,num);
curValue = inf; bestValue = inf;
curSol = newSol; bestSol =newSol;

 T0 = 97; Tf = 3; t = T0;
 p = 1;

 while t >= Tf
     for r = 1:100
         %产生随机扰动
         tmp = ceil(rand*num);
         newSol(1, tmp) =~newSol(1, tmp);

         %检查是否满足约束条件
         while 1
             q = (newSol*weight <= restriction);
             if q 
                 break;
             else
                 p = ~p;
                 tmp1 = find(newSol == 1);
                 if p
                     newSol(1, tmp1) = 0;
                 else
                     newSol(1, tmp1(end)) = 0;
                 end
             end
         end

         newValue = newSol*value;
         if newValue < curValue
             curValue = newValue;
             curSol = newSol;
             if newValue < bestValue
                 bestValue = newValue;
                 bestSol = newSol;
             end
         else
             if rand < exp(-(newValue-curValue)/t)
                 curValue = newValue;
                 curSol = newSol;
             else
                 newSol = curSol;
             end 
         end
     end
     t = t*a;
 end


disp('最优解为：');
disp(bestSol);
disp('背包中物品总价值为：');
bestValue = -bestValue;
disp(bestValue);
disp('背包中物品总重量为：');
disp(bestSol*weight);