From: "Mattias Engdegård" <mattias@virtutech.se>
To: ls-ocaml-developer-2006@m-e-leypold.de
Cc: caml-list@yquem.inria.fr
Subject: Re: [Caml-list] Multiplication of matrix in C and OCaml
Date: Sat, 10 Feb 2007 15:55:46 +0100 [thread overview]
Message-ID: <200702101455.l1AEtkx04882@virtutech.se> (raw)
In-Reply-To: <hbtzxu13d9.fsf@hod.lan.m-e-leypold.de> (ls-ocaml-developer-2006@m-e-leypold.de)
>Just to be sure: Would the compiler be wrong to optimize
>
> c * q > c * k
>
>to just
>
> q > k
With IEEE floating-point it would be wrong for several reasons.
Example 1: q and k are finite but c*q and c*k both are infinite.
Example 2: q and k are small, so that c*q and c*k both are +-0
Example 3: c is NaN but q and k are not.
I'm sure there are other examples involving but not limited to partial or total
loss of precision, positive/negative zero, infinities and NaNs.
next prev parent reply other threads:[~2007-02-10 14:55 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-02-07 23:42 Frédéric Gava
2007-02-08 2:14 ` [Caml-list] " Jacques Garrigue
2007-02-08 9:27 ` Frédéric Gava
2007-02-08 9:38 ` Frédéric Gava
2007-02-08 12:08 ` Jacques Garrigue
2007-02-08 9:56 ` Frédéric Gava
2007-02-08 10:45 ` Xavier Leroy
2007-02-08 15:16 ` Frédéric Gava
2007-02-09 2:58 ` Jacques Garrigue
2007-02-09 9:06 ` ls-ocaml-developer-2006
2007-02-09 10:32 ` ls-ocaml-developer-2006
2007-02-09 14:22 ` skaller
2007-02-09 21:47 ` ls-ocaml-developer-2006
2007-02-09 21:55 ` Andrej Bauer
2007-02-09 22:36 ` ls-ocaml-developer-2006
2007-02-09 23:53 ` Jon Harrop
2007-02-10 1:41 ` ls-ocaml-developer-2006
2007-02-10 2:24 ` Jon Harrop
2007-02-10 14:41 ` ls-ocaml-developer-2006
2007-02-10 14:52 ` Jon Harrop
2007-02-10 15:51 ` ls-ocaml-developer-2006
2007-02-10 16:10 ` Xavier Leroy
2007-02-10 16:11 ` Jon Harrop
2007-02-10 14:55 ` Mattias Engdegård [this message]
2007-02-11 13:13 ` Christophe Raffalli
2007-02-10 1:10 ` Brian Hurt
2007-02-10 1:16 ` Robert Roessler
2007-02-09 23:56 ` Jon Harrop
2007-02-09 12:05 ` Jon Harrop
2007-02-09 12:35 ` ls-ocaml-developer-2006
2007-02-09 13:50 ` Brian Hurt
2007-02-09 14:23 ` Gerd Stolpmann
2007-02-09 14:24 Frederic GAVA
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