replacing matrix rows in a loop

Hi,

I am trying to build a n*k matrix but each row are produced by a function which has a 1*k output. How can I build that? I tried to build a n*k matrix of zeros and replace rows in a loop but since the dimensions are not same, I can't replace rows!

Thanks

[Azzi Abdelmalek]

Provide a short example

[Fred]

This is my function which is a polynomial with k outputs for each X(i) i=1:n and my matrix will be n*k

This is a row for a X(i): [P(1), P(2), ...P(k)]=he_polynomial(1, k, X(i))

Answer 1

[Sean de Wolski]

X = zeros(100,10);      %preallocate
for ii = 1:size(X,1)    %loop over 100 rows
  X(ii,:) = rand(1,10); %insert 10 random numbers
end

Answer 2

[Azzi Abdelmalek]

k=10;
n=20;
X=rand(1,n)
out=cell2mat(arrayfun(@(y) he_polynomial(1,k,X(y)),(1:n)','un',0))