As I understand the Bootstrap Method: you have a set of data which is of size $N_{all}$, and then from this set you select sub-samples of size $N_{sub}$.
Is there a rule of thumb for the size of the subset you should choose? For now I simply take the $N_{all} = N_{sub}$ as for the sub samples repeated values from the original main set may be selected.
Is there a smarter way to choose $N_{sub}$?