On Feb 7, 7:23 am, Case Vanhorsen <cas...@gmail.com> wrote: > On Fri, Feb 4, 2011 at 7:50 AM, Cactus <rieman...@gmail.com> wrote: > > Having been caught once more by the often made, but incorrect, > > assumption that the length of the 'long int' types GMP and MPIR use in > > conversions match the length of limbs, I am wondering if it is time to > > do something about this. > > > This has recently come up several times over on the MersenneForum, > > with more than one plea that we should 'do something about it' by, for > > example, by using a type in these functions that is defined to be of > > the same length as mp limbs. An alternative would be to introduce a > > distinct type for all such uses so that GMP/MPIR users could set the > > actual type used when GMP/MPIR is built. > > Based on my experience with gmpy, I suggest the following: > > Create a parallel set of APIs (mpz_set_sii ??) that accepts a long > long. On platforms with a 32-bit limb and a 64-bit long long, this API > would need to set two limbs. > > If you want to present a single API to the user, you could define a > signed version of mp_limb_t and then define mpz_set_limb as either > mpz_set_si or mpz_set_sii. > > Python has distinct API calls for working with long vs. long long, so > having access to both mpz_set_si and mpz_set_sii works well for me. > > I think the underlying limb type should be chosen for performance and > the API should expose standard C types so I'm not in favor of > specifying the limb type at compile time. > > Another "length of long" issue is the size of mp_bitcnt_t. It is > currently set to unsigned long. I think size_t (which is already used > in mpz_sizeinbase) would be more appropriate.
Thank you for this feedback Case. To have a complete parallel API for long long types would involve a lot of new functions because it is not only the set/get functions that are involved. Are you suggesting that we should just add set/get functions or a complete parallel long long API? In MPIR (not GMP) mp_bitcnt_t is defined as: #ifdef _WIN64 typedef unsigned long long int mp_bitcnt_t; #else typedef unsigned long int mp_bitcnt_t; #endif so it follows the size of limbs. Brian -- You received this message because you are subscribed to the Google Groups "mpir-devel" group. To post to this group, send email to mpir-devel@googlegroups.com. To unsubscribe from this group, send email to mpir-devel+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/mpir-devel?hl=en.
