How to generate pattern randomly In MATLAB
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Hello Everyone, I hope you are doing well.
I have the following pattern , i want to generate this pattern randomly in Matlab.
Y axis values is upto 1000 and and X axis values is also 1000 ( thousand samples) ignore the 0.1 value
The current plot has three levels, i want this levels upto 16 which is generated randomly
for example i have three levels then i have three values which are repeated to complete 1000 samples like the plot below.
can anybody please help me
Davide Masiello on 13 Mar 2022
n = 16; % Number of levels
L = randi(1000,n,1); % Level values
x = 1:1000;
y = ones(size(x)).*L;
Steven Lord on 14 Mar 2022
So to clarify you have a vector of y values:
y = [1 2 3];
that you want to repeat over and over to give a pattern like:
yy = [1 2 3 1 2 3 1 2 3 1 2 3] % etc
If so use the repmat function.
yy2 = repmat(y, 1, 4)
If instead you want each element of the resulting vector to contain one of the values from y chosen at random you can use the randi function.
n = numel(y);
ind = randi(n, 1, 12); % A 1-by-12 vector of random integers between 1 and n
yy3 = y(ind) % Use them as indices into y
Or if you want each element of y to be represented equally often, use randperm to shuffle the elements of yy2.
order = randperm(numel(yy2));
yy4 = yy2(order)
histogram(yy4) % Show the uniform distribution
If you mean something else, please describe in more detail what data you start with and what your ultimate goal is.
Davide Masiello on 14 Mar 2022
Edited: Davide Masiello on 14 Mar 2022
This is another approach based on the comments under my previous answer.
It tries to implement the request by @Med Future that: it generate the the output y which is equal to number of levelsx1000 for eg. 10 level then shape is 10x1000. but i want the same 10x1000 into single row 1x1000 to generate that shape.
To be fair, I am still not sure this is what @Med Future is trying to achieve, but it might be worth a shot.
NOTE: the code below implements the routine by @Image Analyst to compute random values which have a minimum spacing requirement.
numRequired = randi(16,1,1); % However many y values you require.
y = zeros(1, numRequired);
minSpacing = 30; % Whatever.
maxIterations = 100000; % Way more than you think you'll ever need. Failsafe to prevent infinite loop.
loopCounter = 1; % Number of times the loop goes. includes keepers and rejects.
counter = 1; % Index of y
while counter <= numRequired && loopCounter < maxIterations
trial_y = 1000 * rand;
distances = abs(y - trial_y);
if min(distances) > minSpacing
% It's far enough away so keep it.
y(counter) = trial_y;
counter = counter + 1;
loopCounter = loopCounter + 1;
x = 1:1000;
y = repelem(y,floor(length(x)/length(y)));
% completes y up to 1000 values by repeating the start of y
if length(y) < 1000
y(end+1:1000) = y(1:1000-end);