Define a vector with random steps

Question

I want to create an array that has incremental random steps, I've used this simple code.

t_inici=(0:10*rand:100);

The problem is that the random number keeps unchangable between steps. Is there any simple way to change the seed of the random number within each step?

Answer 1

If you have a set number of points, say nPts, then you could do the following

nPts = 10;         % Could use 'randi' here for random number of points
lims = [0, 10]     % Start and end points
x = rand(1, nPts); % Create random numbers  
% Sort and scale x to fit your limits and be ordered 
x = diff(lims) * ( sort(x) - min(x) ) / diff(minmax(x)) + lims(1) 

This approach always includes your end point, which a 0:dx:10 approach would not necessarily.

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If you had some maximum number of points, say nPtsMax, then you could do the following

nPtsMax = 1000;      % Max number of points
lims = [0,10];       % Start and end points
% Could do 10* or any other multiplier as in your example in front of 'rand'
x = lims(1) + [0 cumsum(rand(1, nPtsMax))];     
x(x > lims(2)) = []; % remove values above maximum limit

This approach may be slower, but is still fairly quick and better represents the behaviour in your question.