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Today's Topics:
1. [Bug 3178] one scan is enough to implement ALGstdev_@1 in
monetdb5/modules/kernel/algebra.mx (Yinhe Cao)
2. Announcement: New Oct2012-SP1 Bugfix release of MonetDB suite
(Sjoerd Mullender)
----------------------------------------------------------------------
Message: 1
Date: Tue, 20 Nov 2012 10:01:39 -0800
From: Yinhe Cao <yinhq...@gmail.com>
To: developers-list <developers-l...@monetdb.org>
Subject: [Bug 3178] one scan is enough to implement ALGstdev_@1 in
monetdb5/modules/kernel/algebra.mx
Message-ID:
<cagurnr1duxq6q3vkp-dde5thpj4rgcvjuts61c-d0tgr_ch...@mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"
Hi Fabian,
Thank you very much for your email.
I had the same concern about the accumulation error of one-scan approach as
you do, even though mathematically they should be exactly the same. I
remember about 10 years ago, I did some experimentations on both of the
approaches and I did not found any noticeable differences between the
results, but the sample size I tried then is not huge.
For the sample size of the order 1 trillion, I have the same concern even
with the two-scan approach. For example, After 500 billion entries have
been added to the sum of square, the rest may not be able to be added up
anymore, since it may well with the range of accumulation errors! For a
huge BAT, if the precision is top priority, we may need to use an
hierarchical approach: divide the huge sample into some manageable block,
compute it for each block first, and then aggregate the results.
Thanks,
Yinhe
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Message: 2
Date: Wed, 21 Nov 2012 10:53:02 +0100
From: Sjoerd Mullender <sjo...@acm.org>
To: MonetDB Developers <developers-l...@monetdb.org>, MonetDB Users
<users-l...@monetdb.org>, MonetDB Announcements
<announce-l...@monetdb.org>
Subject: Announcement: New Oct2012-SP1 Bugfix release of MonetDB suite
Message-ID: <13534915821...@dev.monetdb.org>
Content-Type: text/plain; charset=utf-8
The MonetDB team at CWI/MonetDB BV is pleased to announce the
Oct2012-SP1 bugfix release of the MonetDB suite of programs.
More information about MonetDB can be found on our website at
<http://www.monetdb.org/>.
For details on this release, please see the release notes at
<http://www.monetdb.org/Downloads/ReleaseNotes>.
As usual, the download location is <http://dev.monetdb.org/downloads/>.
Oct 2012-SP1 bugfix release
Bug Fixes *?3155: Provide an option for setting discovery to false
*?3161: invalid tuple received from server, got 138 columns,
expected 476, ignoring
*?3182: When using aggregate SQL functions, precision &
decimal metadata for numeric/decimal type returned is 0,0
------------------------------
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End of developers-list Digest, Vol 3, Issue 9
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