From: Alexandre Pilkiewicz <alexandre.pilkiewicz@polytechnique.org>
To: Arlen Cuss <celtic@sairyx.org>
Cc: caml-list@inria.fr
Subject: Re: [Caml-list] Hashtbl: find and find_rec
Date: Mon, 7 Mar 2011 13:00:20 +0100 [thread overview]
Message-ID: <AANLkTimLN9aqxvBwCmRbrxc98nCxDuN-wMaLqMmJy8qE@mail.gmail.com> (raw)
In-Reply-To: <1299479990.22876.15.camel@azayaka>
Hi
2011/3/7 Arlen Cuss <celtic@sairyx.org>:
> Hi all,
>
> I'm puzzling over the OCaml source, and am trying to work out the reason
> for the following definition:
[snip]
> My only guess thus far is that it's cheaper if we don't recurse (stack
> doesn't grow as much, fewer branches), and thus a few levels of testing
> are put in for good measure to speed up the case where it's one of the
> first three items.
>
> Is this it? Or am I missing something else?
I don't think stack is smaller since the find_rec function is tail
recursive. So it is basically loop unrolling (fewer branches).
What I don't really understand is why only do the unrolling on the 3
first iterations. As soon as we have an unrolled version, why not
calling it recursively?
prev parent reply other threads:[~2011-03-07 12:00 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-07 6:39 Arlen Cuss
2011-03-07 12:00 ` Alexandre Pilkiewicz [this message]
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