Random Binary Sequence Generator

I need to generate a Random Binary Sequence of 1x10000 size. Purely Random 1's and 0's.
I had implemented it as follows and it does the job with no complaints.
rand_bin = round(0.75*rand(1,10000));
However, are there any Efficient Implementations for this, probably a specific function which was built for this or something?
Thanks.

4 Commenti

This gives you 1's with probability 1/3 and 0's with probability 2/3. You could also do
ceil(rand(1,10000)-2/3)
or
floor(rand(1,10000)+1/3)
for the same probability, but I doubt if these are any more efficient. I doubt if you can improve on these in any significant way.
Why do you have the factor 0.75 in there? This will give more zeros than ones in the output. Are you sure your need that?
Roger Stafford
Roger Stafford il 3 Feb 2014
Modificato: Roger Stafford il 3 Feb 2014
I assumed that was what was wanted. Otherwise round(rand(1,10000)) is more efficient.
Sam
Sam il 4 Feb 2014
Hi Jos & Roger. Thanks! I didn't realize that the 0.75 was redundant. My idea was to force the random generation to multiply with 0.75 and rounding it but i realize now that it is redundant and forces more 0's..
I agree with Roger's 2nd answer thanks for the clarifications...
Cheers!

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 Risposta accettata

use randi()
x = randi([0 1],10000,1);

3 Commenti

hi, we did the same command but w need to put in polar form. any ideas !!?
Muchas gracias :D
If we want to generate all unique coloums or rows is there a function to do so? any suggestions

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Più risposte (2)

Here are two suggestions:
% with 0 <= P <=1
RBS = rand(1,N) < P
% will give roughly a proportion of P ones among N values
% exactly M ones among N values
RBS = false(1,N) ;
RBS(1:M) = true ;
RBS = RBS(randperm(numel(RBS)
Note: I prefer to store the output as logical arrays (true/false = 1/0) that occupy less memory than double arrays.

2 Commenti

Sam
Sam il 4 Feb 2014
Hi. Thanks! it works as well but i implemented the earlier one as i needed a 1 line solution since the rest of my code is quite lengthy.
That's a poor reason to use a one-lined solution ;-)
Long but efficient and readable code is much preferred over short and efficient but unreadable code.
(btw rand(1,N)<P is both short and readable)

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