particleswarm
粒子群优化
语法
说明
示例
最小化一个包含两个变量的简单函数。
定义目标函数。
fun = @(x)x(1)*exp(-norm(x)^2);
调用 particleswarm 最小化该函数。
rng default % For reproducibility nvars = 2; x = particleswarm(fun,nvars)
Optimization ended: relative change in the objective value over the last OPTIONS.MaxStallIterations iterations is less than OPTIONS.FunctionTolerance. x = 629.4474 311.4814
您可以在函数图中看到，此解远远不是真正的最小值。
fsurf(@(x,y)x.*exp(-(x.^2+y.^2)))
通常，最好设置边界。请参阅 最小化具有边界的简单函数。
最小化一个具有边界约束的包含两个变量的简单函数。
定义目标函数。
fun = @(x)x(1)*exp(-norm(x)^2);
设置变量的边界。
lb = [-10,-15]; ub = [15,20];
调用 particleswarm 最小化该函数。
rng default % For reproducibility nvars = 2; x = particleswarm(fun,nvars,lb,ub)
Optimization ended: relative change in the objective value over the last OPTIONS.MaxStallIterations iterations is less than OPTIONS.FunctionTolerance.
x = 1×2
-0.7071 -0.0000
使用更大的种群和混合函数尝试获得更优解。
指定目标函数和边界。
fun = @(x)x(1)*exp(-norm(x)^2); lb = [-10,-15]; ub = [15,20];
指定选项。
options = optimoptions('particleswarm','SwarmSize',100,'HybridFcn',@fmincon);
调用 particleswarm 最小化该函数。
rng default % For reproducibility nvars = 2; x = particleswarm(fun,nvars,lb,ub,options)
Optimization ended: relative change in the objective value over the last OPTIONS.MaxStallIterations iterations is less than OPTIONS.FunctionTolerance.
x = 1×2
-0.7071 -0.0000
返回可选的输出参量，以更详细地检查求解过程。
定义问题。
fun = @(x)x(1)*exp(-norm(x)^2); lb = [-10,-15]; ub = [15,20]; options = optimoptions('particleswarm','SwarmSize',50,'HybridFcn',@fmincon);
使用所有输出调用 particleswarm 以最小化该函数并获取有关求解过程的信息。
rng default % For reproducibility nvars = 2; [x,fval,exitflag,output,points] = particleswarm(fun,nvars,lb,ub,options)
Optimization ended: relative change in the objective value over the last OPTIONS.MaxStallIterations iterations is less than OPTIONS.FunctionTolerance.
x = 1×2
-0.7071 -0.0000
fval = -0.4289
exitflag = 1
output = struct with fields:
rngstate: [1×1 struct]
iterations: 43
funccount: 2203
message: 'Optimization ended: relative change in the objective value ↵over the last OPTIONS.MaxStallIterations iterations is less than OPTIONS.FunctionTolerance.↵FMINCON: Initial point is a local minimum that satisfies the constraints.↵↵Optimization completed because at the initial point, the objective function is non-decreasing ↵in feasible directions to within the value of the optimality tolerance, and ↵constraints are satisfied to within the value of the constraint tolerance.↵↵<stopping criteria details>↵↵Optimization completed: The final point is the initial point.↵The first-order optimality measure, 2.118144e-07, is less than options.OptimalityTolerance =↵1.000000e-06, and the maximum constraint violation, 0.000000e+00, is less than↵options.ConstraintTolerance = 1.000000e-06.↵'
hybridflag: 1
points = struct with fields:
X: [50×2 double]
Fval: [50×1 double]
输入参数
输出参量
限制
基于问题的优化实时编辑器任务当前不支持指定多个初始点或初始目标函数值。要指定初始点，请使用基于求解器的任务，或使用命令行。
算法
有关粒子群优化算法的描述，请参阅粒子群优化算法。
替代功能
App
优化实时编辑器任务为 particleswarm 提供了一个可视化界面。
