> I'm using them for the process of clustering a huge amount of data
> (posts from an aple blog from the last 4-5 years)I'm counting
> Euclidean distance between two clusters, which I store in a multi_index
> container like the above

> [...]

> My problem is that I have to count 9500! (! = factorial) distances,
> and store them in the multi_index container.

I think I'm misunderstanding this: do you mean your container
is holding 9500! elements? As 9500! ~ 9*10^33664 this can't possibly
be the case.