MATLAB-如何定义多变量目标优化
我试图理解多变量目标优化,我需要优化复杂函数,但首先,我需要优化以下函数:MATLAB-如何定义多变量目标优化,matlab,optimization,Matlab,Optimization,我试图理解多变量目标优化,我需要优化复杂函数,但首先,我需要优化以下函数: function ap_phase = objecfun(tau) f = 1000; %Frequency w = 2*pi*f; %Angular Frequency trans_func = @(taux) (1-1i*w*taux)./(1+1i*w*taux); %Transfer function trans_zero = trans_func(tau(1)); %Trans
function ap_phase = objecfun(tau)
f = 1000; %Frequency
w = 2*pi*f; %Angular Frequency
trans_func = @(taux) (1-1i*w*taux)./(1+1i*w*taux); %Transfer function
trans_zero = trans_func(tau(1)); %Transfer function evaluated with the first variable
trans_quad = trans_func(tau(2)); %Transfer function evaluated with the second variable
ap_phase = rad2deg(phase(trans_zero)-phase(trans_quad)); %Phase difference
end
函数objecfun将一个长度为2的向量作为输入,计算2个传递函数,然后减去传递函数的相位
我的目标是相位应该在90度左右
我用来进行优化的脚本如下
tau0 = [2E-5, 1E-3]; %Initial Value for tau(1) and tau(2)
lb = [1E-7, 1E-7]; %Lower bound for tau(1) and tau(2)
ub = [1E-2, 1E-2]; %Upper bound for tau(1) and tau(2)
goal = 90; %Optimization goal
weight = 1; %Weight
[x,fval] = fgoalattain(@objecfun,tau0,goal,weight,[],[],[],[],lb,ub)
优化器收敛了,但我得到了一个错误的答案
x =
0.0100 0.0000
fval =
-178.1044
那是错误的,fval应该接近90度
我做错了什么?我认为您需要替换您的目标函数和目标值,以便它符合问题公式。您可以使用L2范数作为目标函数,表示函数输出和所需角度之间的差异,并将目标设置为一些公差 我还与fmincon进行了核对:
new_goal = 1e-4;
objectfun = @(x) norm(objecfun(x) - goal);
options = optimoptions('fgoalattain');
options.PlotFcns = 'optimplotfval';
[tau_star,fval] = fgoalattain(objectfun,tau0,new_goal,weight,[],[],[],[],lb,ub,[],options);
options = optimoptions('fmincon');
options.PlotFcns = 'optimplotfval';
[tau_star2,fval,exitflag,output] = fmincon(objectfun,tau0,[],[],[],[],lb,ub,[], options);
fgoalattain_solution_phase_diff = objecfun(tau_star)
fmincon_solution_phase_diff = objecfun(tau_star2)
得到:
fgoalattain_solution_phase_diff =
90.0000
fmincon_solution_phase_diff =
90.0006
注:您也可以在函数中省略rad2deg,并使用[rad]中的值作为所需角度