From: "Randy Brukardt" <randy@rrsoftware.com>
Subject: Re: The answer to "Can Ada replace FORTRAN for numerical computation?
Date: Wed, 24 Jul 2019 18:45:26 -0500
Date: 2019-07-24T18:45:26-05:00 [thread overview]
Message-ID: <qhaqin$t2l$1@franka.jacob-sparre.dk> (raw)
In-Reply-To: 28590d5c-d5f0-4322-9aa4-e1bb92419db3@googlegroups.com
"Lucretia" <laguest9000@googlemail.com> wrote in message
news:28590d5c-d5f0-4322-9aa4-e1bb92419db3@googlegroups.com...
...
> Something like:
>
> M2 := M4 (1, 1 .. 2, 2); -- Makes a copy into the Matrix 2x2 type from a
> 4x4.
This is no problem, of course. What is a problem is the fact that one can
assign into these things and (especially) pass them as "in out" parameters.
That causes overhead for all parameter passing of arrays, whether or not a
multidimensional slice is ever actually used (the compiler cannot assume
that array components are contiguous).
Array slices is one of the features I would remove from "Better Ada". Most
of their utility comes from strings, and (modern) strings are not arrays in
the first place. (I'd also get rid of arrays as a built-in type, making them
a form of container.) A side-effect of that would be to get rid of the
continuing discussion of this "obvious" extension that is way too expensive
to have in Ada (or any language, for that matter). Subprograms can easily
provide the "cheap" functionality, and no one really intends to use
expensive code anyway.
Randy.
next prev parent reply other threads:[~2019-07-24 23:45 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-22 4:38 The answer to "Can Ada replace FORTRAN for numerical computation? Nasser M. Abbasi
2019-07-22 5:53 ` Simon Wright
2019-07-22 10:32 ` Lucretia
2019-07-22 13:20 ` Simon Wright
2019-07-22 17:27 ` Lucretia
2019-07-24 23:45 ` Randy Brukardt [this message]
2019-08-15 16:45 ` Norman Worth
2019-08-15 19:07 ` Dmitry A. Kazakov
2019-08-16 18:29 ` Norman Worth
2019-08-16 19:23 ` Dmitry A. Kazakov
2019-08-18 17:04 ` Norman Worth
2019-07-23 1:35 ` Brad Moore
2019-07-23 23:42 ` Jerry
2019-08-03 12:30 ` Nasser M. Abbasi
2019-08-05 14:35 ` Shark8
2019-08-05 17:15 ` Optikos
2019-08-07 6:35 ` Niklas Holsti
2019-08-07 20:42 ` Optikos
2019-08-16 19:11 ` Norman Worth
2019-08-16 20:15 ` Jeffrey R. Carter
2019-08-17 2:38 ` robin.vowels
replies disabled
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox