How to change a parameter in a model

Question

Gaetano Ruocco 2023-2-27

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回答： Star Strider 2023-2-27

Hi, I'm just getting started using MATLAB and I don't know how to solve this problem.

I have a LTI system described by the following matrices

A = [ -1 0 0; -1 h k; 0 0 -3];

B = [ 1; 1; 0];

C = [0 7 0];

d = [0];

I need to determine the properties of the system for

.

How can I make the parameters automatically change their value ?

Thank you for your help

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Luca Ferro 2023-2-27

h, k should be random beween [-10,10] or linearly increase from -10 to 10 in sync or..?

Gaetano Ruocco 2023-2-27

They should increase by 1 at a time each. I have to consider all the possible couples such as h=-10,k=-10, h=-10,k=-9 and so on

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Answer 1

Luca Ferro 2023-2-27

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Here is one solution:

elements = {-10:1:10, -10:1:10}; %cell array with N vectors to combine

combinations = cell(1, numel(elements)); %set up the varargout result

[combinations{:}] = ndgrid(elements{:});

combinations = cellfun(@(x) x(:), combinations,'uniformoutput',false); %there may be a better way to do this

result = [combinations{:}]; % NumberOfCombinations by N matrix. Each row is unique.

[rows,~]=size(result);

B = [ 1; 1; 0];

C = [0 7 0];

d = 0;

for jj=1:rows

A = [ -1 0 0; -1 result(jj,1) result(jj,2); 0 0 -3]; %h k

%your calculations here

end

Note: for the permutation generation i referenced this answer: https://ch.mathworks.com/matlabcentral/answers/98191-how-can-i-obtain-all-possible-combinations-of-given-vectors-in-matlab#answer_252633

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Answer 2

Star Strider 2023-2-27

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在 MATLAB Online 中打开

Try something like this —

A = @(h,k) [ -1 0 0; -1 h k; 0 0 -3]; % Create As Anonymous Function

B = [ 1; 1; 0];

C = [0 7 0];

d = [0];

ssfcn = @(h,k) ss(A(h,k),B,C,d); % Create As Anonymous Function

[H,K] = ndgrid(-10:10); % Grids Of (h,k) Values

hk = [H(:), K(:)]; % Matrix Of (h,k) Values (Avoids Nested Loops)

wv = logspace(-3, 2, 75)*2*pi; % Radian Frequency Vector

figure

tiledlayout(5,5) % Change To Plot Different Numbers Of PArameters

% for kk = 1:size(hk,1) % Plot All Val;ues

for kk = 1:fix(size(hk,1)/24):size(hk,1) % Plot Subset Of Values

nexttile

[mag,phs,w] = bode(ssfcn(hk(kk,1),hk(kk,2)), wv);

semilogx(w, mag2db(squeeze(mag)))

grid

ylim([-50 30])

title(sprintf('h=%3d, k=%3d',hk(kk,:)))

end

I use bode here, however any function you want will likely work, with appropriate changes in the plot call and arguments to the function you are plotting. (The tiledlayout function does not work directly with bode or bodeplot, so it is necessary to get the outputs and plot them separately. The same is likely true for other Control System Toolbox functions that produce plots.)

.