Greetings!
Richard Fateman <fateman@cs.berkeley.edu> writes:
> Regarding CLOS or similar approaches.
>
> There was a tendency in programming macsyma originally to
> "traffic in body parts". This might cause problems in making
> a clean approach to types. Thus for the CRE form, we sometimes
> decapitated the form, and used only (cdr ..) of the form.
>
> For bigfloats, the equivalent is knowing that you have a bigfloat,
> and decapitating it, so you just have a list of exponent and fraction,
> with the precision set as a global variable, and the fact that you
> are dealing with a BIGFLOAT, implicit in the program that is being
> called.
>
> Maybe this causes no problems and insignificant inefficiencies
> compared to the time saved by not having to debug things.
>
> For what it is worth, there are major major advantages in speed, for
> numbers that are just a few words long, from using GMP instead of
> the home-grown bigfloats. I think GCL already uses GMP, no? If so,
> using a few more interfaces may make this facility much faster.
>
Greetings! GMP upstream has just broken out the multi-precision
floating point into a separate library, mpfr, which we do not use at
present. It would be very straightforward to provide analogous mpf_
functions to the mpz_ functions currently available in GCL. Asked
Paul Dietz some time ago about possible bigfloat uses in a lisp
implementation, and it seemed a little less than promising due to the
fixed precision nature of certain parts of the spec. Please correct
me if wrong.
Take care,
> RJF
>
> Raymond Toy wrote:
>
> >>>>>>"Mike" == Mike Thomas <mike.thomas@brisbane.paradigmgeo.com> writes:
> > Mike> I accidentally deleted a couple of emails re CLOS and ANSI
> > GCL and Ray's
> > Mike> proposal so can't reply directly to those.
> > Mike> PCL is indeed part of ANSI GCL and can be brought into the
> > maxima package on
> > Mike> the current stable release of Windows Maxima (after running "to_lisp()" )
> > Mike> with "use-package" as follows:
> > I take it it mean PCL is available, but isn't really quite integrated
> > into ansi gcl yet.
> > Mike> Errors about the class named "real" occur with Ray's code
> > as shown below.
> > Mike> I'm not well versed (or chaptered, for that matter, if you'll forgive my
> > Does that mean that gcl doesn't know about the Lisp type REAL?
> > That's
> > supposed to be standard. Or maybe my example code is wrong, and I
> > should have said cl:real instead.
> > I'd try to make this work, but I don't have a recent build of gcl.
> > Ray
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>
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>
>
--
Camm Maguire camm@enhanced.com
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