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Ian McCulloch
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 Posted: Wed Nov 05, 2003 11:08 pm Post subject: Why no shuffle_output in the proposed random number facility |
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Hi,
I was just looking over the additions that have been accepted for the LTR.
What immediately stuck out was in the random number library, the
shuffle_output engine is in the list of engines "considered for inclusion,
but left out for the following reasons:". But, in the case of
shuffle_output, no reason is given. Indeed, the 'comments' section is only
complementary: "compound engine that reorders the base engine's output,
little overhead for generation (one multiplication)". It almost looks like
it could be an editorial mistake that it was not in the previous table.
Rationale please?
That aside, the most useful realization of this engine (at least for
monte-carlo) is the floating-point version: pick a table entry by
int(floor(R * Table.size())). Or is there some adaptor that would do this
automatically from the int version? And why not have the table size as a
parameter? The *extremely* paranoid might want to choose a table size that
is a prime, for example....
Algorithm "A" from Knuth might be another candidate for inclusion.
Cheers,
Ian McCulloch
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Pete Becker
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| Posted: Thu Nov 06, 2003 1:27 am Post subject: Re: Why no shuffle_output in the proposed random number faci |
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Ian McCulloch wrote:
| Quote: |
I was just looking over the additions that have been accepted for the LTR.
What immediately stuck out was in the random number library, the
shuffle_output engine is in the list of engines "considered for inclusion,
but left out for the following reasons:". But, in the case of
shuffle_output, no reason is given. Indeed, the 'comments' section is only
complementary: "compound engine that reorders the base engine's output,
little overhead for generation (one multiplication)". It almost looks like
it could be an editorial mistake that it was not in the previous table.
Rationale please?
|
There are many things that could have been included. Almost all of them
weren't.
--
Pete Becker
Dinkumware, Ltd. (http://www.dinkumware.com)
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[ comp.std.c++ is moderated. To submit articles, try just posting with ]
[ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ]
[ --- Please see the FAQ before posting. --- ]
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James Kuyper
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| Posted: Fri Nov 07, 2003 6:35 am Post subject: Re: Why no shuffle_output in the proposed random number faci |
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[email]petebecker (AT) acm (DOT) org[/email] (Pete Becker) wrote in message news:<3FA99CB4.C816BFC7 (AT) acm (DOT) org>...
| Quote: | Ian McCulloch wrote:
I was just looking over the additions that have been accepted for the LTR.
What immediately stuck out was in the random number library, the
shuffle_output engine is in the list of engines "considered for inclusion,
but left out for the following reasons:". But, in the case of
shuffle_output, no reason is given. Indeed, the 'comments' section is only
complementary: "compound engine that reorders the base engine's output,
little overhead for generation (one multiplication)". It almost looks like
it could be an editorial mistake that it was not in the previous table.
Rationale please?
There are many things that could have been included. Almost all of them
weren't.
|
The question was "why?". Also, why is the reason (whatever it is)
missing from the "comments" section?
---
[ comp.std.c++ is moderated. To submit articles, try just posting with ]
[ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ]
[ --- Please see the FAQ before posting. --- ]
[ FAQ: http://www.jamesd.demon.co.uk/csc/faq.html ]
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Pete Becker
Guest
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| Posted: Fri Nov 07, 2003 8:17 pm Post subject: Re: Why no shuffle_output in the proposed random number faci |
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James Kuyper wrote:
| Quote: |
[email]petebecker (AT) acm (DOT) org[/email] (Pete Becker) wrote in message news:<3FA99CB4.C816BFC7 (AT) acm (DOT) org>...
Ian McCulloch wrote:
I was just looking over the additions that have been accepted for the LTR.
What immediately stuck out was in the random number library, the
shuffle_output engine is in the list of engines "considered for inclusion,
but left out for the following reasons:". But, in the case of
shuffle_output, no reason is given. Indeed, the 'comments' section is only
complementary: "compound engine that reorders the base engine's output,
little overhead for generation (one multiplication)". It almost looks like
it could be an editorial mistake that it was not in the previous table.
Rationale please?
There are many things that could have been included. Almost all of them
weren't.
The question was "why?".
|
Yes, that is the question that I replied to. Listing reasons for not
including all the things that weren't included would be a tedious and
pointless task.
| Quote: | Also, why is the reason (whatever it is)
missing from the "comments" section?
|
If it really matters, ask the person who wrote the paper.
--
Pete Becker
Dinkumware, Ltd. (http://www.dinkumware.com)
---
[ comp.std.c++ is moderated. To submit articles, try just posting with ]
[ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ]
[ --- Please see the FAQ before posting. --- ]
[ FAQ: http://www.jamesd.demon.co.uk/csc/faq.html ]
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Edward Diener
Guest
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| Posted: Sat Nov 08, 2003 12:27 am Post subject: Re: Why no shuffle_output in the proposed random number faci |
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Pete Becker wrote:
| Quote: | James Kuyper wrote:
[email]petebecker (AT) acm (DOT) org[/email] (Pete Becker) wrote in message
news:<3FA99CB4.C816BFC7 (AT) acm (DOT) org>...
Ian McCulloch wrote:
I was just looking over the additions that have been accepted for
the LTR. What immediately stuck out was in the random number
library, the shuffle_output engine is in the list of engines
"considered for inclusion, but left out for the following
reasons:". But, in the case of shuffle_output, no reason is
given. Indeed, the 'comments' section is only complementary:
"compound engine that reorders the base engine's output, little
overhead for generation (one multiplication)". It almost looks
like it could be an editorial mistake that it was not in the
previous table. Rationale please?
There are many things that could have been included. Almost all of
them weren't.
The question was "why?".
Yes, that is the question that I replied to. Listing reasons for not
including all the things that weren't included would be a tedious and
pointless task.
|
No one asked for the reasons for not including everything which wasn't
included. Someone asked only for the reasons for not including
shuffle_output.
---
[ comp.std.c++ is moderated. To submit articles, try just posting with ]
[ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ]
[ --- Please see the FAQ before posting. --- ]
[ FAQ: http://www.jamesd.demon.co.uk/csc/faq.html ]
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Pete Becker
Guest
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| Posted: Sat Nov 08, 2003 2:58 am Post subject: Re: Why no shuffle_output in the proposed random number faci |
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Edward Diener wrote:
| Quote: |
Pete Becker wrote:
James Kuyper wrote:
[email]petebecker (AT) acm (DOT) org[/email] (Pete Becker) wrote in message
news:<3FA99CB4.C816BFC7 (AT) acm (DOT) org>...
Ian McCulloch wrote:
I was just looking over the additions that have been accepted for
the LTR. What immediately stuck out was in the random number
library, the shuffle_output engine is in the list of engines
"considered for inclusion, but left out for the following
reasons:". But, in the case of shuffle_output, no reason is
given. Indeed, the 'comments' section is only complementary:
"compound engine that reorders the base engine's output, little
overhead for generation (one multiplication)". It almost looks
like it could be an editorial mistake that it was not in the
previous table. Rationale please?
There are many things that could have been included. Almost all of
them weren't.
The question was "why?".
Yes, that is the question that I replied to. Listing reasons for not
including all the things that weren't included would be a tedious and
pointless task.
No one asked for the reasons for not including everything which wasn't
included. Someone asked only for the reasons for not including
shuffle_output.
|
Look it up in the list of things that weren't included. It's a rather
long list, and it doesn't give many reasons, but maybe you'll luck out.
--
Pete Becker
Dinkumware, Ltd. (http://www.dinkumware.com)
---
[ comp.std.c++ is moderated. To submit articles, try just posting with ]
[ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ]
[ --- Please see the FAQ before posting. --- ]
[ FAQ: http://www.jamesd.demon.co.uk/csc/faq.html ]
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