Random number with no repeats in set matrix

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Rainaire Hansford 2019-4-14

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评论： Walter Roberson 2019-6-28

采纳的回答： Walter Roberson

Hello again.

I want to make a matrix with random numbers that do not repeat in each row in a k X p matrix

and can be modified depending on inputs.

So far i have a code:

clc
k=input('# rows ');
p=input('# columns')
S=randperm(p);
S=S(1:(k*p));
S=reshape(S,k,p)

This works some times but not all the times.

Please help?

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Walter Roberson 2019-4-20

编辑：Walter Roberson 2019-4-20

在 MATLAB Online 中打开

hasdup = any( sum(bsxfun(@eq, s, permute(unique(s), [2 3 1])),2) > 1, 3);

Now hasdup is true for the rows of s which contain duplicate values within the row (and so you will need to regenerate the row.)

It is not clear to me why you do not use the sort-based code that I posted: it is guaranteed that the rows of S will contain unique integers in the range 1 to p with no need to regenerate.

Rainaire Hansford 2019-4-20

it is because i wanted to change the range any time so far it only give me number 1 to 5 at random.

How do i get it to give me number from 1 to 100 but I want a k by p matrix?

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采纳的回答

Walter Roberson 2019-4-14

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在 MATLAB Online 中打开

Old trick that randperm() used to implement:

[~, S] = sort(rand(k, p), 2);

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Rainaire Hansford 2019-5-23

Also this code will not allow me to run mutliple rows for S. When I change "k" to 2 or more it will give a error saying Im out of bound or something like so.

Rainaire Hansford 2019-6-4

What can I do to make my code find any amount of matching numbers and not all of them?

Please provide example. Thank you

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Steven Lord 2019-6-21

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You have a requirement that no row may contain the same number twice. Can different rows in the same matrix contain the same number? So in the example below, A would not be acceptable (the second row has two 3's) but B would be acceptable (the first and second rows each have 2)?

A = [1 2; 3 3];
B = [1 2; 2 3];

If so, call randperm once for each row, telling it to generate size(B, 2) numbers from 1 to your upper limit.

nrows = 10;
ncols = 7;
maxvalue = 100;
A = zeros(nrows, ncols);
for whichrow = 1:nrows
    A(whichrow, :) = randperm(maxvalue, ncols);
end

If you call rng default immediately before calling that code the resulting matrix should have three rows that contain the number 4 and three rows that contain 89, but that neither 4 nor 89 repeat in the same row.

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Rainaire Hansford 2019-6-21

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https://ww2.mathworks.cn/matlabcentral/answers/456326-random-number-with-no-repeats-in-set-matrix#answer_380247

What can I do to make my code find any amount of matching numbers and not all of them?

Please provide example. Thank you

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Rainaire Hansford 2019-6-28

What do you mean?

Walter Roberson 2019-6-28

You can use reshape and bsxfun to compare each member of one array to each member of another, resulting in a k by s by w by p array. You then any() along one of the dimensions and sum along a different dimension and squeeze to get a 2d array of results.

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