From mboxrd@z Thu Jan  1 00:00:00 1970
Received: (from weis@localhost) by pauillac.inria.fr (8.7.6/8.7.3) id RAA21986 for caml-red; Thu, 19 Oct 2000 17:13:26 +0200 (MET DST)
Received: from concorde.inria.fr (concorde.inria.fr [192.93.2.39]) by pauillac.inria.fr (8.7.6/8.7.3) with ESMTP id NAA16951 for <caml-list@pauillac.inria.fr>; Thu, 19 Oct 2000 13:37:11 +0200 (MET DST)
Received: from pauillac.inria.fr (pauillac.inria.fr [128.93.11.35])
	by concorde.inria.fr (8.11.1/8.10.0) with ESMTP id e9JBb8L07024;
	Thu, 19 Oct 2000 13:37:08 +0200 (MET DST)
Received: (from xleroy@localhost) by pauillac.inria.fr (8.7.6/8.7.3) id NAA17371; Thu, 19 Oct 2000 13:37:07 +0200 (MET DST)
Message-ID: <20001019133707.42818@pauillac.inria.fr>
Date: Thu, 19 Oct 2000 13:37:07 +0200
From: Xavier Leroy <Xavier.Leroy@inria.fr>
To: Chris Hecker <checker@d6.com>
Cc: caml-list@inria.fr
Subject: Re: single-precision floats, etc.
References: <Chris <4.3.2.7.2.20001016110744.01e9d660@shell16.ba.best.com> <vtuog0i45mw.fsf@gala.lifl.fr> <4.3.2.7.2.20001018081700.033cdef0@walt>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
X-Mailer: Mutt 0.89.1
In-Reply-To: <4.3.2.7.2.20001018081700.033cdef0@walt>; from Chris Hecker on Wed, Oct 18, 2000 at 08:20:43AM -0700
Sender: weis@pauillac.inria.fr

> >I think that maybe what you are looking for is the bigarray library
> >that appeared with ocaml 3.00.
> 
> I looked at that, but I really wanted to do the actual operations in
> caml code, not in a library (if possible).  So, I'd like to write an
> LU decomposition routine in caml that's as fast as C code (or close
> enough), for example.  Going out to another language is inconvenient
> at best, compared to just writing down the code you want (like you
> would in C).

I don't understand your point.  The bigarray library provides support
for large numerical arrays with the associated operations, but you
still write the code that use these arrays in Caml.  Indeed, the code
is almost the same as if you'd used the standard array type; you just
write b.{x} and b.{x,y} instead of a.(x) and a.(x).(y).

*You* are not "going out to another language"; the system might, in
order to implement some of the bigarray operations (and some of the
regular array operations as well!), but why should you care?

Now, it is true that one of the goals of the Bigarray library is to
facilitate interoperability with C and Fortran code: by having the
same array layout as these languages, arrays can be passed back and
forth without copying.  But you may ignore this aspect of the library
for now, and just use it in Caml for working with large, compact arrays
of numbers.

- Xavier Leroy