On Sun, Mar 8, 2009 at 8:27 PM, William Stephens <wstephen...@suddenlink.net> wrote: > Hello, > > I was working on a sieve of eratosthenes and ran into an error I don't > understand. > >>>> size = 10 000 000 000 >>>> l = [0,1]*(size/2) > Traceback (most recent call last): > File "<stdin>", line 1, in <module> > OverflowError: cannot fit 'long' into an index-sized integer > > > Is there a type or something that I can do to prevent this error? Or am I on > the wrong track for such large primes?
The maximum size of a list is given by Py_ssize_t in pyport.h in the Python source and discussed in PEP 353: http://www.python.org/dev/peps/pep-0353/ My understanding is that list size is limited to the maximum signed integer supported by the underlying C compiler. On a 32-bit processor this is 2**31 = 2,147,483,647 which is a bit smaller than your requested 10,000,000,000. But...think about what you are asking for. Each array element is 8 bytes (a pointer) so you are trying to create a 80,000,000,000 byte array. That's about 74 gigabytes before you even try to put any values in it. So, yes, I think you are on the wrong track... Kent _______________________________________________ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
