On Aug 25, 9:59 pm, Jason Moxham <ja...@njkfrudils.plus.com> wrote: > On Tuesday 25 August 2009 20:35:48 Juanjo wrote: > > I think that the cheapest solution is the one you suggested: allocate > > the bignums manually and hope that GMP does not reallocate them. This > > can be easily done in ECL, because the actual bignum creation is > > restricted to a few functions in src/c/big.d. In all calculations with > > bignums the procedure is as follows: > > 1* Identify bignum operands > > 2* Create one or more intermediate operators as GMP integers with > > some preallocated limbs. > > 3* Perform the calculations using the intermediate operators. > > 4* Create a bignum object from the intermediate value. > > 5* Clear that intermediate operator. > > Steps 2,3,5 would work even with Sage's allocator, just by ensuring > > that step 5* uses mpz_clear (Right now we do not need it). Step 4* > > would be the only one to change, manually allocating the memory that > > GMP needs. > > GMP will still need to allocate memory for internal needs using its > allocator, > but it is freed again . If the destination operand has enough memory for the > largest possible output +1 then this should be enough , although I dont know > if we can guarantee it , or if we want to( ie if we guarantee it now , then > we have to forever)
I think you do not understand steps 4 and 5: we already KNOW the size of the memory that we have to allocate using ECL's allocator. We will be simply copying an integer created by GMP to a location that is private for ECL and that neither GMP nor ECL will manage -- it belongs to the garbage collector. After creating ECL's copy, the integer created with GMP can be cleared. As I said, allocation and deallocation of intermediate values can be done using Sage's memory manager, for ECL will guarantee that every integer which is created will be destroyed as well. Juanjo --~--~---------~--~----~------------~-------~--~----~ To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
