Minimization and Optimization. Minimize output by optimizing inputs

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Anand Ra 2021-10-6

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评论： Anand Ra 2021-10-11

Hello

Trying to minimize the output by finding the optimium input values. I am unable to construct the minimization part of the code with the constrains I have. Any help would be greatly appreciated.

% Objective:Optimize the lengths to minimze the power using a new variable.

a = 0.1:20;

b = 0.1:20;

d = a + 0.1:20;

c = b + 0.1:20;

e = d + 0.1:20

%Constants

k= 2;

w=1;

v=1.5

%Variables and their constrains

AB = sqrt(a.^2 + b.^2);

BC = sqrt( c.^2 + ((e-d)/2).^2 );

CS = sqrt( c.^2 + ((e-d)/2).^2 );

VAB = sqrt(((((a.*v).^2/(((b.^2).*4))) + (v^2)/2 )));

% VBS = sqrt(((a*v)^2/((4*b*b)) + (v^2)/2 ));

VCS = ((2*c)./(e-d)).*sqrt(AB.^2);

VBC= CS.^2 + BC.^2;

%Actual Power

%P = (AB.*VAB + BC.*VBC + CS.*VCS).*k*w; % Power

% Objective

%To search and find the values for a, b, c d and e to minimize power (P)

% Not sure how to write the function for above

% fun = @(x)(x(:,1) + x(:,2) + x(:,3) + x(:,4) + x(:,5)).*k.*w;

% [X1, X2, X3, X4, X5] = ndgrid(0:.1:2); % Should I give this condition in a nested loop?

% X = [X1(:), X2(:), X3(:), X4(:), X5(:)];

% P = fun(X);

% [bestP, idx] = min(P(:))

% best_X = X(idx,:)

采纳的回答

Alan Weiss 2021-10-6

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https://ww2.mathworks.cn/matlabcentral/answers/1468246-minimization-and-optimization-minimize-output-by-optimizing-inputs#answer_802906

Sounds like you would be best served with the Problem-Based Optimization Workflow. Declare the variables that can change as optimization variables, set the problem objective to P, and call solve.

Alan Weiss

MATLAB mathematical toolbox documentation

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Alan Weiss 2021-10-7

在 MATLAB Online 中打开

If you look at the objective function value

[sol,fval] = solve(prob,x0)

you find that the different solutions all have the same objective function value. So there are many solutions. Is this unexpected? This is not something that I can tell you how to fix. it is for you to determine whether the problem is formulated correctly.

Alan Weiss

MATLAB mathematical toolbox documentation

Anand Ra 2021-10-11