On Dec 28, 2:13 am, Mark Dickinson <dicki...@gmail.com> wrote: > On Dec 28, 6:50 am, Mensanator <mensana...@aol.com> wrote: > > > > > But with a 64-bit processor, that limitation no longer stops me. > > > i: 11 bits: 10,460,353,205 decimals: 3,148,880,080 > > i: 12 bits: 94,143,178,829 decimals: 28,339,920,715 > > > Wow! 94 billion bits! 28 billion decimal digits! > > > Of course, once one wall falls, you get to go up against the next > > one. > > For generation 13, I get: > > > gmp: overflow in mpz type > > Abort trap > > > Hmm, not sure what "overflow" means in this context, but I suspect > > it ran out of memory, I probably should have gotten the MacBook Pro > > with 8 GB of ram. But then, maybe it wouldn't help. > > I don't think this was due to running out of memory: it looks like > gmp uses the 'int' C type to count the number of limbs in an mpz, > which would make the maximum number of bits 2**31 * 64, or around 137 > billion, on a typical 64-bit machine. Maybe there's a configure > option to change this? > > For Python longs, the number of limbs is stored as a signed size_t > type, so on a 64-bit machine memory really is the only limitation. > > -- > Mark
Based on comments on the GMP website, the maximum number of bits on a 64-bit platform is limited to 2**37 or 41 billion decimal digits. A number this size requires 16GB of RAM. A future version of GMP (5.x) is supposed to remove that limit and also work well with disk-based storage. casevh -- http://mail.python.org/mailman/listinfo/python-list
