How store vector output in matrix row

Hi,

I'm trying to write a program in order to store a vector output in a matrix like this:

for k=1:K % number of iterations
  for i=1:Sg(i) % Sg is a vector line of K samples
index(i,:)= randsample(1:length(matFragt), Sg(i));% matFragt is a KxK matrix
  end
end

What i want is to randomly select (Sg(i)) samples in the matFragt row matrix and store each iteration in a matrix. this proposition gives an error:

" Subscripted assignment dimension mismatch."

I tried to create a cell but it gives me false result

Can any one help me please.

[Walter Roberson]

If your Sg values are not all the same, then the first time you get to an Sg(i) that is not the same as the previous Sg(i-1) then the length of the random vector will be different than what is already stored, and you would have problems storing the result into index(i,:) because the row size would not be the same as the previous row.

[oufouanas]

thank you for your reply, yes Sg values are not the same. I tried to create a cell

  B = cell(1, K);
 for n=1:K
    for i=1:Sg(i)
    B{n} = randsample(1:length(matFragt), Sg(i));
    end
 end
 

but in each element of the cell is not egal to Sg(i) and i don't get K iterations.

[Walter Roberson]

You have a problem in your limit in your for i loop: you have the upper bound as Sg(i) but i has not yet been assigned a value.

It seems strange to me that the number of times you want to generate random samples just happens to be the same as the number of random samples you want to generate.

Answer 1

[Walter Roberson]

nFrag = length(matFragt);
nSG = length(Sg);
B = cell(K, nSG);
for n = 1 : K
    for i = 1 : nSG
        B{n, i} = randperm(nFrag, Sg(i));
    end
end