create big matrix with only 0s and 1s

I want to run the following

 n = 10^6;
 m = n/2;
 H = sparse(m,n);
 parfor jj=1:n
     pos = sample(cumulative);
     H(:,jj) = (rand(m,1) > 1 - degrees(pos)/m);     
 end

but the memory is over.

degrees(pos)/m is a different number every time. Is there any way to run it quickly?

Answer 1

[the cyclist]

Unless I did the math in my head wrong, you are trying to create a matrix that is 4 terabytes of data (and is not actually sparse). That's too big.

[Image Analyst]

theodor, why do you need it that big? You'll just have to get by without the whole thing in memory at once. You'll have to figure out how to process the thing in smaller chunks.

[freebil]

thanks for the answers.. I actually don't need zeros but only 1s.. Is there any way to create a sparse matrix with only ones? I thought something like that

 finalcolpos=0;

 parfor jj=1:n
        pos = sample(cumulative);
        col = (rand(m,1) > 1 - degrees(pos)/m);
        colpos = find(col);
        finalcolpos = [finalcolpos; colpos];
 end

 finalcolpos(1)=[];
 H(finalcolpos)=1;

but it is slow for n>10^5