Creating unknown-dimension array while executing

Hello everyone, I am trying to program decision-making in a maze. In this system there are N1 steps where you have to decide between n different paths. The number of paths per step doesn't have to be the same for each step.

Well, the thing is that I want the program to be able to work whatever number of steps are predefined at the beginning, and I want to store the probabilities of taking different decisions at different steps in a vector of the kind: u(1,3,1,2...) where the column would correspond to step 1,2,.. and the number in the column to the path chosen in each particular step.

I don't know if that's possible, and there are probably other ways of doing it, but I think this one is the most convenient for this particular problem.

Thanks a lot

Answer 1

[J. Webster]

As you probably know, to create an array where you know the number of elements, you can use

X = zeros(1,N);

That's preferred, but if you don't have any way of knowing how big the array will be, you can start off with an empty array and then grow it...

X = [];
while somecondition
    newX = something;
    X = [X newX];       %#ok<AGROW>
end

The %#ok<AGROW> is to keep Matlab from complaining about growing an array inside a loop.