How to randomly change element of matrix?

% Set the random number generator seed, for repeatability here
rng default
% Size of matrix
n = 3;
% Starting matrix -- use your real data instead
M = magic(n);
% Loop two times
for ii = 1:2
    % Chose random element index (using linear index)
    rndIdx = randi(n*n);
    % Change the random element to a random value from 1:1000 (which I guess is what you want?)
    M(rndIdx) = randi(1000)
    % Put save step here, if you want to save each one
end
M = 3×3
     8     1     6
     3     5   906
     4     9     2
M = 3×3
     8     1     6
   914     5   906
     4     9     2

This code keep going forward from the original matrix, changing elements one at a time (but sometimes it could overwrite the same location more than once). You'll need to adjust the code if you want to start from M, save, start from original M again, etc.

But hopefully you get the idea.

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the cyclist 2021-9-14

在 MATLAB Online 中打开

% Set the random number generator seed, for repeatability here
rng default
% Size of matrix
n = 3;
% Starting matrix -- use your real data instead
M = magic(n);
% Loop two times
for ii = 1:2
    % Chose random element index (using linear index)
    rndIdx = randi(n*n);
    % Change the random element to a random value from 1:1000 (which I guess is what you want?)
    Mnew = M;
    Mnew(rndIdx) = randi(1000)
    % Put save step here, if you want to save each one
end
Mnew = 3×3
     8     1     6
     3     5   906
     4     9     2
Mnew = 3×3
     8     1     6
   914     5     7
     4     9     2

Ammy 2021-9-14

Thank you very much.

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Answer 2

Fabio Freschi 2021-9-14

2
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1453174-how-to-randomly-change-element-of-matrix#answer_787289

在 MATLAB Online 中打开

You can use linear indexing

% your matrix
A = rand(10,100);
% create the folder
mkdir('storage');
% loop
for i = 1:100
    % random matrix
    Arand(randi(numel(A))) = rand;
    % save
    save(strcat('./storage/mymatrix',num2str(i),'.mat'));
end