[Caml-list] variable sharing

[Caml-list] variable sharing

[Kihong Heo]

Dear caml-list.

I want to know how ocaml compiler make variable sharing.
I believe the compiler do good job, but sometime memory consumption
of my program does not make sense. 
So I am curious about what the compiler did or how to make program memory efficiently.

If you know some good notes or web pages for that issue, please let me know.

Thank you.

- Kihong Heo

Re: [Caml-list] variable sharing

[Yitzhak Mandelbaum]

Kihong,

Could you elaborate on what you mean by "variable sharing" and what specifically is not happening as expected? Perhaps you could provide a small example that demonstrates the problem you're seeing?

Cheers,
Yitzhak


On Mar 6, 2011, at 8:49 PM, Kihong Heo wrote:

> Dear caml-list.
> 
> I want to know how ocaml compiler make variable sharing.
> I believe the compiler do good job, but sometime memory consumption
> of my program does not make sense. 
> So I am curious about what the compiler did or how to make program memory efficiently.
> 
> If you know some good notes or web pages for that issue, please let me know.
> 
> Thank you.
> 
> - Kihong Heo
> 
> -- 
> Caml-list mailing list.  Subscription management and archives:
> https://sympa-roc.inria.fr/wws/info/caml-list
> Beginner's list: http://groups.yahoo.com/group/ocaml_beginners
> Bug reports: http://caml.inria.fr/bin/caml-bugs
> 

-----------------------------
Yitzhak Mandelbaum

Re: [Caml-list] variable sharing

[Kihong Heo]

Sorry. It's my mistake. 
not variable sharing, but "value sharing" which means alias.

For example, there is a big set and I want to make many subset of it.
In my thought, if the aliases are made efficiently, the memory explosion does not make sense.
I don't know exactly what's the problem (my programming style, data type, or it is a natural result, etc..).
So I want to know the principle.

Thank you.
Kihong

2011. 3. 7., 오전 11:07, Yitzhak Mandelbaum 작성:

> Kihong,
> 
> Could you elaborate on what you mean by "variable sharing" and what specifically is not happening as expected? Perhaps you could provide a small example that demonstrates the problem you're seeing?
> 
> Cheers,
> Yitzhak
> 
> 
> On Mar 6, 2011, at 8:49 PM, Kihong Heo wrote:
> 
>> Dear caml-list.
>> 
>> I want to know how ocaml compiler make variable sharing.
>> I believe the compiler do good job, but sometime memory consumption
>> of my program does not make sense. 
>> So I am curious about what the compiler did or how to make program memory efficiently.
>> 
>> If you know some good notes or web pages for that issue, please let me know.
>> 
>> Thank you.
>> 
>> - Kihong Heo
>> 
>> -- 
>> Caml-list mailing list.  Subscription management and archives:
>> https://sympa-roc.inria.fr/wws/info/caml-list
>> Beginner's list: http://groups.yahoo.com/group/ocaml_beginners
>> Bug reports: http://caml.inria.fr/bin/caml-bugs
>> 
> 
> -----------------------------
> Yitzhak Mandelbaum
> 
> 
> 

--
허 기 홍 드림
khheo@ropas.snu.ac.kr
서울대학교 프로그래밍 연구실

Re: [Caml-list] variable sharing

[Daniel Bünzli]

Value sharing will not depend on the compiler but on your programing
style (and the style of the libraries you use).

When you code you should always ask yourself whether you are recycling
the values you manipulate or whether you are doing new copies of the
same data.

You may also be interested in implementing hash consing [1] for your
data structures.

Best,

Daniel

[1] http://www.lri.fr/~filliatr/ftp/publis/hash-consing.ps.gz

Re: [Caml-list] variable sharing

[Fabrice Le Fessant]

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let a = ...
let b = Some a
let c = b (* b and c share the same value *)
let d = Some a (* d = b,  but d != b, i.e. b and d don't share the same
value in memory *)

If you want b and d to share the same value, you have to use some kind
of h-consing, but the runtime won't do it for you by default.

--Fabrice
INRIA -- OCamlPro

On 03/07/2011 03:25 AM, Kihong Heo wrote:
> Sorry. It's my mistake. 
> not variable sharing, but "value sharing" which means alias.
> 
> For example, there is a big set and I want to make many subset of it.
> In my thought, if the aliases are made efficiently, the memory explosion does not make sense.
> I don't know exactly what's the problem (my programming style, data type, or it is a natural result, etc..).
> So I want to know the principle.
> 
> Thank you.
> Kihong
> 
> 2011. 3. 7., 오전 11:07, Yitzhak Mandelbaum 작성:
> 
>> Kihong,
>>
>> Could you elaborate on what you mean by "variable sharing" and what specifically is not happening as expected? Perhaps you could provide a small example that demonstrates the problem you're seeing?
>>
>> Cheers,
>> Yitzhak
>>
>>
>> On Mar 6, 2011, at 8:49 PM, Kihong Heo wrote:
>>
>>> Dear caml-list.
>>>
>>> I want to know how ocaml compiler make variable sharing.
>>> I believe the compiler do good job, but sometime memory consumption
>>> of my program does not make sense. 
>>> So I am curious about what the compiler did or how to make program memory efficiently.
>>>
>>> If you know some good notes or web pages for that issue, please let me know.
>>>
>>> Thank you.
>>>
>>> - Kihong Heo
>>>
>>> -- 
>>> Caml-list mailing list.  Subscription management and archives:
>>> https://sympa-roc.inria.fr/wws/info/caml-list
>>> Beginner's list: http://groups.yahoo.com/group/ocaml_beginners
>>> Bug reports: http://caml.inria.fr/bin/caml-bugs
>>>
>>
>> -----------------------------
>> Yitzhak Mandelbaum
>>
>>
>>
> 
> --
> 허 기 홍 드림
> khheo@ropas.snu.ac.kr
> 서울대학교 프로그래밍 연구실
> 
> 
> 

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email;internet:fabrice.le_fessant@inria.fr
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Re: [Caml-list] variable sharing

[Julien Signoles]

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Hello,

2011/3/7 Kihong Heo <khheo@ropas.snu.ac.kr>

> Sorry. It's my mistake.
> not variable sharing, but "value sharing" which means alias.
>
> For example, there is a big set and I want to make many subset of it.
> In my thought, if the aliases are made efficiently, the memory explosion
> does not make sense.
> I don't know exactly what's the problem (my programming style, data type,
> or it is a natural result, etc..).
> So I want to know the principle.
>

As Daniel and Fabrice said, I guess you need hash-consing. You may use the
Filliâtre's Hashcons/Hset/Hmap modules (
http://www.lri.fr/~filliatr/software.en.html) described in [1]. If you want
to know details about interaction between hashconsing and ocaml (especially
its GC), [2] may be of some interest to you.

[1] Sylvain Conchon and Jean-Christophe Filliâtre. Type-Safe Modular
Hash-Consing. ML Workshop'06.
[2] Pascal Cuoq and Damien Doligez, Hashconsing in an incrementally
garbage-collected system: a story of weak pointers and hashconsing in ocaml
3.10.2. ML Workshop'08.

Hope this helps,
Julien



> 2011. 3. 7., 오전 11:07, Yitzhak Mandelbaum 작성:
>
> > Kihong,
> >
> > Could you elaborate on what you mean by "variable sharing" and what
> specifically is not happening as expected? Perhaps you could provide a small
> example that demonstrates the problem you're seeing?
> >
> > Cheers,
> > Yitzhak
> >
> >
> > On Mar 6, 2011, at 8:49 PM, Kihong Heo wrote:
> >
> >> Dear caml-list.
> >>
> >> I want to know how ocaml compiler make variable sharing.
> >> I believe the compiler do good job, but sometime memory consumption
> >> of my program does not make sense.
> >> So I am curious about what the compiler did or how to make program
> memory efficiently.
> >>
> >> If you know some good notes or web pages for that issue, please let me
> know.
> >>
> >> Thank you.
> >>
> >> - Kihong Heo
> >>
> >> --
> >> Caml-list mailing list.  Subscription management and archives:
> >> https://sympa-roc.inria.fr/wws/info/caml-list
> >> Beginner's list: http://groups.yahoo.com/group/ocaml_beginners
> >> Bug reports: http://caml.inria.fr/bin/caml-bugs
> >>
> >
> > -----------------------------
> > Yitzhak Mandelbaum
> >
> >
> >
>
> --
> 허 기 홍 드림
> khheo@ropas.snu.ac.kr
> 서울대학교 프로그래밍 연구실
>
>
>
> --
> Caml-list mailing list.  Subscription management and archives:
> https://sympa-roc.inria.fr/wws/info/caml-list
> Beginner's list: http://groups.yahoo.com/group/ocaml_beginners
> Bug reports: http://caml.inria.fr/bin/caml-bugs
>
>

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