* [Caml-list] int hash
@ 2004-07-14 9:33 skaller
2004-07-14 12:16 ` [Caml-list] " Julian Brown
0 siblings, 1 reply; 6+ messages in thread
From: skaller @ 2004-07-14 9:33 UTC (permalink / raw)
To: caml-list
I'm currently using a lot of hashtables with
sequentially allocated integers as keys.
It occurs to me a custom hash function just
masking in the low n bits would be a good hash
function, and very fast, assuming n is chosen
suitably and related somehow to the table
size. (size=2^n?) .. any comments on the performance
of a hashtable with such a hash function?
--
John Skaller, mailto:skaller@users.sf.net
voice: 061-2-9660-0850,
snail: PO BOX 401 Glebe NSW 2037 Australia
Checkout the Felix programming language http://felix.sf.net
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^ permalink raw reply [flat|nested] 6+ messages in thread
* [Caml-list] Re: int hash
2004-07-14 9:33 [Caml-list] int hash skaller
@ 2004-07-14 12:16 ` Julian Brown
2004-07-14 14:27 ` skaller
2004-07-14 15:32 ` henri dubois-ferriere
0 siblings, 2 replies; 6+ messages in thread
From: Julian Brown @ 2004-07-14 12:16 UTC (permalink / raw)
To: caml-list
On 2004-07-14, skaller <skaller@users.sourceforge.net> wrote:
> I'm currently using a lot of hashtables with
> sequentially allocated integers as keys.
Could you not use DynArray from ExtLib instead?
Julian
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^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [Caml-list] Re: int hash
2004-07-14 12:16 ` [Caml-list] " Julian Brown
@ 2004-07-14 14:27 ` skaller
2004-07-14 14:46 ` Richard Jones
2004-07-14 15:32 ` henri dubois-ferriere
1 sibling, 1 reply; 6+ messages in thread
From: skaller @ 2004-07-14 14:27 UTC (permalink / raw)
To: brown; +Cc: caml-list
On Wed, 2004-07-14 at 22:16, Julian Brown wrote:
> On 2004-07-14, skaller <skaller@users.sourceforge.net> wrote:
> > I'm currently using a lot of hashtables with
> > sequentially allocated integers as keys.
>
> Could you not use DynArray from ExtLib instead?
For some things .. not necessarily this one .. DynArray
would be great .. but it creates a dependence on an
unstable third party LGPL'd library. I can neither
lift the relevant code (due to the licence),
nor lightly require my clients install that library
just to build my product. [I have seriously considered
requiring ExtLib]
BTW: I should explain the hashtables map
"arbitrary" subsets of the first n integers,
where n grows as time goes on
(fresh variable' generator),
and there are a quite a few of these tables
built (its a compiler, there is a table for
every symbol representing its children).
--
John Skaller, mailto:skaller@users.sf.net
voice: 061-2-9660-0850,
snail: PO BOX 401 Glebe NSW 2037 Australia
Checkout the Felix programming language http://felix.sf.net
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^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [Caml-list] Re: int hash
2004-07-14 14:27 ` skaller
@ 2004-07-14 14:46 ` Richard Jones
2004-07-14 21:29 ` skaller
0 siblings, 1 reply; 6+ messages in thread
From: Richard Jones @ 2004-07-14 14:46 UTC (permalink / raw)
Cc: caml-list
On Thu, Jul 15, 2004 at 12:27:50AM +1000, skaller wrote:
> For some things .. not necessarily this one .. DynArray
> would be great .. but it creates a dependence on an
> unstable third party LGPL'd library. I can neither
> lift the relevant code (due to the licence),
> nor lightly require my clients install that library
> just to build my product. [I have seriously considered
> requiring ExtLib]
I almost consider ExtLib to be part of "standard OCaml", along with
PCRE. It's easier just to have both installed whenever I set up a new
machine with OCaml, than to have to worry about writing the extra code
to simulate functionality already in ExtLib.
(I also have my own mini-library which is installed everywhere by
default, but I'm trying to push most of that code into ExtLib :-)
Rich.
--
Richard Jones. http://www.annexia.org/ http://www.j-london.com/
Merjis Ltd. http://www.merjis.com/ - improving website return on investment
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^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [Caml-list] Re: int hash
2004-07-14 14:46 ` Richard Jones
@ 2004-07-14 21:29 ` skaller
0 siblings, 0 replies; 6+ messages in thread
From: skaller @ 2004-07-14 21:29 UTC (permalink / raw)
To: Richard Jones; +Cc: caml-list
On Thu, 2004-07-15 at 00:46, Richard Jones wrote:
> On Thu, Jul 15, 2004 at 12:27:50AM +1000, skaller wrote:
> > For some things .. not necessarily this one .. DynArray
> > would be great .. but it creates a dependence on an
> > unstable third party LGPL'd library. I can neither
> > lift the relevant code (due to the licence),
> > nor lightly require my clients install that library
> > just to build my product. [I have seriously considered
> > requiring ExtLib]
>
> I almost consider ExtLib to be part of "standard OCaml", along with
> PCRE. It's easier just to have both installed whenever I set up a new
> machine with OCaml, than to have to worry about writing the extra code
> to simulate functionality already in ExtLib.
>
That is reasonable for an Ocaml developer (which I am),
but not as clearly reasonable for a *client* of my
code who is probably not. I feel the need to supply
a system consisting of the smallest number of
separately installable components for obvious
reasons: every dependence on a third party component
makes my package fragile. For example, I'd like it
to install on Win32 native.. I don't have control
of third party packages so how do i respond when
a client has a problem?
Note the problem *isn't* the quality of the third
party code! Its sure to be better than mine :)
I have a client that installs my package on 5 different
platforms (his product is a multi-platform game, it runs
on OSX, Linux[both PC and XBox], OS9, Cygwin and Mingw
at present).
This problem may be substantially corrected by GODI
because it provides a *unified* installation system.
--
John Skaller, mailto:skaller@users.sf.net
voice: 061-2-9660-0850,
snail: PO BOX 401 Glebe NSW 2037 Australia
Checkout the Felix programming language http://felix.sf.net
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^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [Caml-list] Re: int hash
2004-07-14 12:16 ` [Caml-list] " Julian Brown
2004-07-14 14:27 ` skaller
@ 2004-07-14 15:32 ` henri dubois-ferriere
1 sibling, 0 replies; 6+ messages in thread
From: henri dubois-ferriere @ 2004-07-14 15:32 UTC (permalink / raw)
To: brown; +Cc: caml-list
Dynarray looks great but is possibly not rock solid at this point.
(last i used it was in a long running simulation which ended up
segfaulting while in the dynarray code - unfortunately i was unable to
get an easily reproducible case).
henri
On Wed, 14 Jul 2004 12:16:39 +0000 (UTC), Julian Brown
<brown@cs.bris.ac.uk> wrote:
> On 2004-07-14, skaller <skaller@users.sourceforge.net> wrote:
> > I'm currently using a lot of hashtables with
> > sequentially allocated integers as keys.
>
> Could you not use DynArray from ExtLib instead?
>
> Julian
>
>
>
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^ permalink raw reply [flat|nested] 6+ messages in thread
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2004-07-14 9:33 [Caml-list] int hash skaller
2004-07-14 12:16 ` [Caml-list] " Julian Brown
2004-07-14 14:27 ` skaller
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2004-07-14 21:29 ` skaller
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