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Re: gmp issues (long)
From: |
Rob Browning |
Subject: |
Re: gmp issues (long) |
Date: |
Tue, 25 Feb 2003 14:08:41 -0600 |
User-agent: |
Gnus/5.090008 (Oort Gnus v0.08) Emacs/21.2 (i386-pc-linux-gnu) |
Stephen Compall <address@hidden> writes:
> Rob Browning wrote:
> replace the _mp_size field with a short, since I doubt that we'd
> ever be likely to overflow long data[MAX_SHORT] digits. (What was
> the size limit, if any, on our old bignums?).
>
> My first use of GMP in C (after the requisite playing around while
> learning) was to try to build up a Godel number as an example in a
> project involving semigroups I'm working on (OT). After creating one of
> these numbers, I believe the memory usage of the mpz_t & friends was ~5
> MB. While this was an abnormal case, it's still far off from 256k.
> er....
Wow. That's a pretty giant number :>
OK. If we want to accomodate numbers this big without a 2-tier hybrid
approach, or something, people should adjust my storage computations
to account for a 4-byte size rather than a 2-byte-size.
Also, just for comparison, and presuming I read the code correctly,
our previous implementation used a 16-bit (plus sign bit) size field,
so moving to a 4-byte size field would be a substantial increase over
what we supported before.
--
Rob Browning
rlb @defaultvalue.org, @linuxdevel.com, and @debian.org
Previously @cs.utexas.edu
GPG starting 2002-11-03 = 14DD 432F AE39 534D B592 F9A0 25C8 D377 8C7E 73A4
- gmp issues (long), Rob Browning, 2003/02/24
- Re: gmp issues (long), Marius Vollmer, 2003/02/25
- Re: gmp issues (long), Rob Browning, 2003/02/25
- Re: gmp issues (long), Marius Vollmer, 2003/02/25
- Re: gmp issues (long), Rob Browning, 2003/02/25
- Re: gmp issues (long), Marius Vollmer, 2003/02/25
- Re: gmp issues (long), Rob Browning, 2003/02/25
- Re: gmp issues (long), Kevin Ryde, 2003/02/26