opensource

credit: C G-K

Renaming rgslffi to gsl4r. Might as well. Hopefully I won't wake up tomorrow and decide to call it Moon Child. Project page in the works http://gsl4r.rubyforge.org Git repository already available in alpha-planning stages:
git clone git://rubyforge.org/gsl4r.git

While working on rgslffiGSL4r, I needed to define a mapping for the gsl_complex struct (we'll ignore for now that gsl_complex is potentially platform dependent).

Here's my attempt:

  class GSL_Complex < ::FFI::Struct
    layout :dat, [:double, 2]

    R = 0
    I = 1

    def real()
      return self[:dat][R]
    end

    def imag()
      return self[:dat][I]
    end

    def equals( a )
      return ( a[:dat][R] == self[:dat][R] && a[:dat][I] == self[:dat][I] )
    end

    def set( r, i )
      self[:dat][R] = r
      self[:dat][I] = i
      return self
    end

    def set_real( r )
      self[:dat][R] = r
    end

    def set_imag( i )
      self[:dat][I] = i
    end

    def to_s()
      return "(#{self[:dat][R]},#{self[:dat][I]})"
    end
  end

I was stumped for a few hours on passing FFI::Structs into external routines, luckily, this post, 'Functions returning structures' (groups/google/ruby-ffi), tipped me off by showing how to return a struct by value:

From the C code:

...
    typedef struct
    { 
        int r, g, b, a; 
    } ALLEGRO_COLOR; 
...

setiquest

Each year, the non-profit "Technology, Entertainment, Design" or TED Group, holds a conference with invited speakers from around the world, in a kind-of "Big Thinkers" hoedown.

In 2009, Jill Tarter, a director and co-founder of the SETI Institute in Mountain View, CA, won a TEDPrize, which comes with funding to help jump start a wish that the prize winner would like to see fulfilled. Jill's wish is being fleshed out by the work of Avinash Agrawal and the creation of http://www.setiquest.org

A major part of setiquest will be to take raw data from the Allen Telescope Array and load it into cloud computing services donated by Amazon. Those who sign up with setiquest will then help create algorithms to search for signals that might be hidden in the noise.

credit:C G-K

Now available, the 1.1.5 release of log4r (See: http://log4r.rubyforge.org or gem install -r log4r)

Addressed in 1.1.5:
FileOutputter no longer truncates files by default
Syntax fixed up in GDC/NDC classes to work in Ruby 1.9 as well as 1.8

I'm also quite happy about the move to hosting ruby gems at http://gemcutter.org. Its helped me become aware of how widely log4r is a pre-requisite for other software. Since I started new releases last September (2009), it was downloaded over 21,000 times, with the 1.1.4 release on January 12, 2010, downloaded 12,000+ times alone.

*nervous*

http://www.omnipotent.net/jquery.sparkline

Filing away into the possibly very useful bin, dojokit, a javascript library, appears to have a very decent dynamic charting (real-time data flow) API:

See: dojox.charting
See: dojox

credit: JFree.org

In the interest of having snappy plotting software for use on the ATA software, I'm experimenting with jfreechart and how it updates a dynamic plot, and jfreechart's admitted performance issue:

From section 10.2.2 of the jfreechart 1.0.13 Developer Guide:

10.2.2 Performance
Regarding performance, you need to be aware that JFreeChart wasn’t designed specifically for generating real-time charts. Each time a dataset is updated, the ChartPanel reacts by redrawing the entire chart. Optimisations, such as only drawing the most recently added data point, are
difficult to implement in the general case, even more so given the Graphics2D abstraction (in the Java2D API) employed by JFreeChart. This limits the number of “frames per second” you will be able to achieve with JFreeChart. Whether this will be an issue for you depends on your data, the requirements of your application, and your operating environment.

I was wondering if the drawing was offloaded to opengl (and therefore more on the graphics card), that this updating process might be improved for this admittedly 2D focused work. I'm doing this on my core 2 duo mac pro, ~2007, which has 2 GeForce 7300's in it (not top of the line, but no slouch).