Create an array from others matrix

I need to put "a" matrix one below the other in a single matrix. That is, I need to place in a matrix of dimension a*b x N, where the first b rows correspond to sec=1, from row b+1 to row 2b+1 the second matrix corresponding to sec=2, and so on.

For example for this code:

a=100;
b=5;
N=8;

for sec=1:a
    PM=rand(b,N)
end

I want to create the matrix of dimension 500x8, formed by the 100 matrix generated, where the first 5 rows correspond to the matrix obtained for sec = 1, from row 6 to row 11 the second matrix corresponding to the matrix obtained for sec = 2, and so on.

[Bob Thompson]

Why do you want 6-11 to be for 2sec? There were only five rows for the first second.

Where is your data coming from? Or is it just randomly generated numbers?

Assuming that you have data, I would use something like the following:

for i = 1:100
    data((i-1)*5+1:i*5,:) = rand(5,8);
end

[Romina]

My data comes from another code and not from this. In the original code something similar happens, then, for every second i get a 1000 x 1000 matrix.

There were only five rows for the first second and five rows for sec 2. It's 6-10 and not 6-11 as i said before

[Bob Thompson]

Ok, well the indexing on 'data' should be what you're looking for. I can't write the right hand side of the equation for you because I don't know what it looks like.

Answer 1

[Fabio Freschi]

You can just append the matrices as they come.

a=100;
b=5;
N=8;
% inital empty matrix
PM = [];

% your loop
for sec=1:a
    PM = [PM; rand(b,N)];
end

[Fabio Freschi]

Of course you can also preallocate

a=100;
b=5;
N=8;

% inital zero matrix
PM = zeros(a*b,N);

% your loop
for sec=1:a
    idx = (1:b)+(sec-1)*b;
    PM(idx,:) = rand(b,N);
end

[Romina]

I tried to transfer this idea to my code but I can't get what I want. Thanks anyway

[Fabio Freschi]

If you can be more precise, I would try to help

[Fabio Freschi]

If I understand correctly the method works. After this section:

        ...
        %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
        %%%% I NEED SAVE IN A MATRIZ PotMem, this 10 Potenciales_Membrana matrix,
        Potenciales_Membrana(t,1:N)=v
        u=u+a.*(0.2*v-u);
        STDP(:,t+D+1)=0.95*STDP(:,t+D);
    end

put these lines

        
    idx = (1:c)+(sec-1)*c;
    PotMem(idx,:) = Potenciales_Membrana;

and in the end you should have PotMem filled with Potenciales_Membrana. Let me know if it is what you need.

[Romina]

Yes! That is exactly what I needed! Thank you very very much!

[Fabio Freschi]

My pleasure! If my answer solve your original problem, please accept it!