Difficulty implementing simulated annealing algorithm

Question

Abbi Hashem 2019-6-25

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/468810-difficulty-implementing-simulated-annealing-algorithm

评论： Abbi Hashem 2019-6-25

采纳的回答： Stephan

在 MATLAB Online 中打开

While there are exaplanations for this (see the following link), I couldn't figure out exactly how to implement it:

https://www.mathworks.com/help/gads/examples/minimization-using-simulated-annealing-algorithm.html

This is the code that I am typing, based on the info in the link:

type simple_objective
function y = simple_objective(x)
x1 = x(1);
x2 = x(2);
y = (4-2.1.*x1.^2+x1.^4./3).*x1.^2+x1.*x2+(-4+4.*x2.^2).*x2.^2;
ObjectiveFunction = @simple_objective;
x0 = [0.5 0.5];   % Starting point
rng default % For reproducibility
[x,fval,exitFlag,output] = simulannealbnd(ObjectiveFunction,x0)

I don't understand what exactly is wrong with that code (I keep getting an error). I am very new to MATLAB and would appreciate any help!

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Answer 1

Stephan 2019-6-25

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链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/468810-difficulty-implementing-simulated-annealing-algorithm#answer_380732

在 MATLAB Online 中打开

rng default % For reproducibility
x0 = [0.5 0.5];   % Starting point
[x,y,flag,output] = simulannealbnd(@simple_objective,x0)
function y = simple_objective(x)
x1 = x(1);
x2 = x(2);
y = (4-2.1.*x1.^2+x1.^4./3).*x1.^2+x1.*x2+(-4+4.*x2.^2).*x2.^2;
end

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Stephan 2019-6-25

在 MATLAB Online 中打开

did you exactly copy my code? it runs for me with result:

Optimization terminated: change in best function value less than options.FunctionTolerance.
x =
   -0.0896    0.7130
y =
   -1.0316
flag =
     1
output = 
  struct with fields:
     iterations: 2948
      funccount: 2971
        message: 'Optimization terminated: change in best function value less than options.FunctionTolerance.'
       rngstate: [1×1 struct]
    problemtype: 'unconstrained'
    temperature: [2×1 double]
      totaltime: 1.1943