How do I create a n by n matrix, randomly filled with only k specific values ; m1,m2,m3..mk where m1, m2, m3..mk are specified
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Tarun Cousik
on 10 Nov 2016
Commented: James Tursa
on 11 Nov 2016
Example
Say I want a 3 by 5 matrix filled randomly with only 2 particular values 2 and 6
A=
2 6 2 2 6; 6 2 6 6 2; 2 2 6 2 2;
I'm thinking of using a function like Rand and combine it with a round function, any tips/solutions are much appreciated!
-Tarun
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Accepted Answer
Image Analyst
on 10 Nov 2016
Edited: Image Analyst
on 10 Nov 2016
Try this:
myNumbers = [2.3, pi] % Whatever
% Find out how many unique numbers there are.
numNumbers = length(unique(myNumbers))
% Create a labeled 3-by-5 matrix with values from 1 to numNumbers
m = randi(numNumbers, 3, 5)
% Now replace each integer label ID of m with the value from myNumbers
for k = 1 : numNumbers
m(m == k) = myNumbers(k);
end
% Print to command window:
m
In the command window you'll see:
myNumbers =
2.3 3.1416
numNumbers =
2
m =
1 2 1 2 2
2 1 1 1 2
1 2 1 1 2
m =
2.3 3.1416 2.3 3.1416 3.1416
3.1416 2.3 2.3 2.3 3.1416
2.3 3.1416 2.3 2.3 3.1416
It's generalizable to any numbers you want to use, not just integers, and any number of rows and columns.
3 Comments
Image Analyst
on 11 Nov 2016
That's far simpler. Simply use randi():
m = 2 * randi([0,1], 100) - 1
James Tursa
on 11 Nov 2016
If you just want -1 or +1, then see this link:
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