Subject: Re: [boost] [review] Multiprecision review scheduled for June 8th - 17th, 2012
From: Jeffrey Lee Hellrung, Jr. (jeffrey.hellrung_at_[hidden])
Date: 2012-06-05 11:30:29
On Thu, May 31, 2012 at 12:58 AM, Marc Glisse <marc.glisse_at_[hidden]> wrote:
> (sorry for the broken thread, I wasn't subscribed yet)
> A few quick comments:
> * gmpxx != mpfr_class
> * the version of gmpxx in the repository hasn't used any temporary for the
> example given in the introduction for a while, it is only because of a slow
> release cycle that you haven't seen it yet (will be in 5.1).
> * the example about using 0 vs 11 temporaries doesn't mention what happens
> to the boost package if we disable expression template. Does it use a
> single temporary (using rvalue-references) or plenty?
> * having an implicit narrowing conversion from double to bigint is a bad
> idea, it should be explicit (it isn't completely obvious from the doc if
> that is the case).
> * you could get good results with a backend that uses gmp's mpn_*
> functions but not the mpz_t type.
> * what about infinite precision floats? By that I mean something like
> bigint*2^n, where operations + - * are computed exactly. It can be quite a
> bit faster than rationals, when it is sufficient.
> * if I want reference-counting, I guess that should be done in a back-end.
Thanks for the pre-review comments, Marc; it's good to get such detailed
exposure prior to the formal review! I'm doing my best to track your
Boost list run by bdawes at acm.org, gregod at cs.rpi.edu, cpdaniel at pacbell.net, john at johnmaddock.co.uk