German English

Original by Ronald Jeffries, translation by Aleksi Niemela and Dave Thomas. www.rubycentral.com/articles/pink/index.html

From the README:

Major features:

• Cholesky decomposition
• LU decomposition
• QR decomposition
• Schur decomposition
• Singular value decomposition
• Eigenvalues and eigenvectors of a general matrix
• Minimization by least squares
• Linear equation solving
• Stand-alone LAPACK bindings: call any LAPACK routine from directly from ruby.

Welcome to my little book. In it, my goal is to teach you a way to think about computation, to show you how far you can take a simple idea: that all computation consists of sending messages to objects. Object-oriented programming is no longer unusual, but taking it to the extreme - making everything an object - is still supported by only a few programming languages.

Can I justify this book in practical terms? Will reading it make you a better programmer, even if you never use "call with current continuation" or indulge in "metaclass hackery"? I think it might, but perhaps only if you’re the sort of person who would read this sort of book even if it had no practical value.

The real reason for reading this book is that the ideas in it are neat. There’s an intellectual heritage here, a history of people building idea upon idea. It’s an academic heritage, but not in the fussy sense. It’s more a joyous heritage of tinkerers, of people buttonholing their friends and saying, "You know, if I take that and think about it like this, look what I can do!"

link

LinuxTag program

This situation provides much of the motivation for our architecture, ERP5, which offers several advantages for business. All ERP5 tools are open source, so are free and have openly available source code that a business can change to suit its processes. ERP5 incorporates, from scratch, advanced concepts such as object-oriented databases, a content management system, synchronization, variations, workflows, and a method to model and implement business processes. ERP5 is also a Web site where researchers can share innovation on management techniques and their implementation through software.

In 2001, two companies initiated the ERP5 project: Nexedi, a Zope service provider in France (Zope is a well-known open-source application server), and Coramy, a European apparel manufacturer. They aimed to develop a set of ERP software components for small and medium-sized companies. In addition to source code, the project also produced educational material and a clearly defined theoretical model. To fit the needs of smaller companies, they also designed ERP5 for distribution across distant sites with slow and unreliable Internet connections.

link

 I have run Compiere251d with Oracle10g & Java 1.5 beta :-), and I am very nice.

 You have to make the step:

 1.- Copy the $ORACLE_HOME/jdbc/lib/ojdbc14.jar
 to $COMPIERE_HOME/lib/oracle10g.jar

 2.- Change into $COMPIERE_HOME/RUN_setup.sh  in the -classpath oracle.jar for
 oracle10g.jar

Some very interesting ruby stuff:

• Artificial Neural Networks: Implemented a multilayer backpropagating artificial neural network using a momentum term and optionally a weight decay term.
• Borges mod_ruby Integration: I have managed to get Borges running using mod_ruby. I will produce a library ready version of that and check it in the Borges project.
• and much more
link

How well does the Oracle-compatability mode work for SAP DB? I got to check that as it might be an option to replace the existing Oracle DB dependency.

I will post a few pics from the Linuxtag later. Not too many people here this year. Linux has simply made it into mainstream. The adventure has long gone :-). Got a nice yellow "no software patents" t-shirt.

 GM> Are there any accepted or already practiced ways for
 GM> companies to prevent Ruby source code from being read by potential
 GM> competitors? I can vaguely imagine redefining Ruby's
 GM> "require"-type methods so they can include zipped and passworded
 GM> ".rbz" files, say. Or using exerb (except for UNIX and without the
 GM> potential license issues).

 GM> I want to use Ruby at work but this is one of those "steps to
 GM> convincing your boss to use Ruby" I need to go through.

Just look at the "eval.c" file, i think the require is defined there and then write your hook. Or write a dll/so and add embedd your rb files as large c strings there (using maybe the "wrap" tool from the Fox Toolkit) and then do rb_eval_string("my c file"). After this protect the dll with something like "armadillo" (use google to find the URL). This works perfectly for me.

link

The Springz library allows you to attach two objects together (in 2D space) with a spring, and simulate how they pull/push each other.

Boring when used between two objects, it becomes interesting when you attach thousands of springs with different strenghts and distances between hundreds of nodes, and let the simulation determine the best configuration of those nodes. (I wrote this library specifically to create a social network diagram from a large amount of data. I had written it first in Javascript + SVG, and it was working, but too slowly: 3 hours to render the first frame, and 12+ hours for each frame after that.)

Despite the very visual nature of this application, this library doesn't know jack about graphics; it just knows how to push/pull theoretical objects around in theoretical 2D space. Making this visible to the user is up to you. (My application reads in XML data and then outputs a few frames of SVG pre-rendered animation.)

The documentation for the Springz class lists the key features at the top of it. You can read this laboriously-written documentation, and download the file itself, from: here (click on Springz.rb under the Files listing).

If you happen to have the Adobe SVG plugin (freely avail for Win/Mac/Linux/Solaris) installed, you can see the JS version of this library in action at -- click the green rectangle to start the simulation, and then drag objects around and/or click the orange button to scatter them about.

 The Ruby Production Archive (RPA) will provide packages of Ruby
 libraries and programs in a form that allows production use, engineered
 through a stringent process resembling FreeBSD's or Debian's.

 rpa-base is a port/package manager designed to support RPA. Its scope and
 purposes are different to those of other systems like RubyGems.

 rpa-base 0.1.0 is now available on http://rpa-base.rubyforge.org .
 Please keep in mind that this is *not* a RPA release (that is, a release
 of the repository) but just a release of the rpa-base tool itself. We
 have provided several sample ports/packages for testing purposes, but
 they don't formally belong to RPA. Read below for information on the
 libs/apps packaged so far.

 rpa-base requires Ruby 1.8.1 (certainly 1.8 at least, it might work on
 1.8.0); it has been tested on several Linux distributions, FreeBSD and
 win32. We would appreciate feedback (both positive and negative) under
 those or any other architecture.

 It takes but a couple minutes to install and will allow you to do

 rpa install instiki ruvi

 ;-)
 (NOTE: ruvi, the cool pure-Ruby vim clone, won't work on win32)

 Features
 ========

 rpa-base is a port/package manager designed to support RPA's client-side
 package management. You can think of it as RPA's apt-get + dpkg. It
 features the following (working right now):

  * sane dependency management: rpa-base installs dependencies as needed,
    keeps track of reverse dependencies on uninstall, and will remove no
    longer needed dependencies
  * atomic (de)installs: operations on the local RPA installation are atomic
    transactions; the system has been designed to survive ruby crashes (OS
    crashes too on POSIX systems)
  * modular, extensible design: the 2-phase install is similar to FreeBSD and
    Debian's package creation; rpa-base packages need not be restricted
    to installing everything under a single directory ("1 package, 1 dir"
    paradigm)
  * rdoc integration: RDoc documentation for libraries is generated at install
    time (currently disabled on win32)
  * ri integration: ri data files are generated for all the libraries managed
    by RPA; you can access this information with ri-rpa (currently disabled on
    win32)
  * handling C extensions: if you have the required C toolchain, rpa-base can
    compile extensions as needed
  * unit testing: when a library is installed, its unit tests are run; the
    installation is canceled if they don't pass

I just now came across this link on slashdot. The only thing I can say is that like in the RIAA (sic) cases one really wonders about our politicians. And this is the weakest way of putting it .. oh boy! Lessing has said it correctly: *If we don’t fight for our freedom, we do not deserve it*. I am so sick of all these stupid trivial patents like double-click, hyperlinks, etc. .. does anybody care that obvious prior art exists?

The /. link

Some nice quotes :-)

 Ministers were being trusted to represent the view of the government that sent
 them... but it seems as if business interests have found that these
 individuals are a weak link that can easily be "bought off" and convinced to act
 on their own.

 The corporations won the war.

Sven C. Koehler has started to read "Numerical Methods for Scientists and Engineers". He was so kind to send me a few quotes he likes from the introduction.

 Most books on computing stress the estimation of roundoff,
 especially the bounding of roundoff, but we shall concentrate
 on the avoidance of roundoff.  It seems better to avoid roundoff
 than to estimate what did not have to occur if common sense and
 few simple rules had been followed before the problem was put on
 the machine.

 Another standard algorithmic problem both in mathematics and in the use
 of computation to solve problems is the solution of simultaneous linear
 equations.  Unfortunately much of what is commonly taught is usually not
 relevant to the problem as it occurs in practice; nor is any completely
 statisfactory method of solution known at present.  Because the solution
 of simultaneous linear equations is so often a standard library package
 supplied by the computing center and because the corresponding
 description is so often misleading, it is necessary to discuss the
 limitations (and often the plain foolishness) of the method used by the
 package.  Thus it is necessary to examine carefully the obvious flaws and
 limitations, rather than pretending they do not exist.

update: (sorry, German only;) A big thanks to Sven C. Koehler for this summary

 Ich habe es nun in den groessten Teilen ueberflogen.  Die Ideen sind nicht
 wirklich neu: Umformen von Gleichungen, Vermeiden ungefaehr gleichgrosse
 Zahlen von einander abzuziehen, Approximation.  Beim Loesen von
 Gleichungssystemen schlägt er z.B. vor, ein Verfahren einzusetzen, das
 kein wiederholtes Dividieren benoetigt, dann wird's auch nicht ungenau.
 Trotzdem mag ich das Buch, weil es in mir den Eindruck weckt, dass es
 sehr fundiert ist.  Es ist voll von mathematischen Formeln, die ich alle
 nicht wirklich verstanden habe, aber ich werde in jedem Fall wieder darin
 nach Erklaerungen suchen, wenn ich mal wieder ein Numerik-Problem habe.

 Ich glaube für dich ist as Buch eher langweilig, das meiste kennst du
 bestimmt aus dem Studium. :-)