Sarl is a library designed to support formal concept analysis. Sarl3 is the third incarnation of the Sarl library. Sarl1 was first written in C, Sarl2 was written in Ocaml, and Sarl3 has been written in C with a Ruby interface.
Currently the only version of Sarl3 is the content of the CVS repository. Checkout the module "sarl3", then change to the sarl3 directory, edit config.mak for your installation and run make.
Requirements include: gnome2-dev, gtk2-dev, gnome2-ruby, tcltk, ruby, g++
As the project becomes more mature it is intended to construct a debian package for Sarl3.
Following is an example to give a flavour of the library.
require 'sarl' def create_bn_lattice(n) context = Context.new for g in 1..n do for m in 1..n do if g != m then context.insert(g,m) end end end return Lattice.new(context) end
The first thing to notice about this example is that objects and attributes are numbers. This is a central feature of the Sarl library. It operates over integers. Of course the integers have meanings which can be stored in a string table. However these meanings are only important for presentation, not calculation of the lattices so they do not play a large part in the library.
require 'sarl' st = StringTable.new() st = "one" st = "two"
Let us now consider calculating the join irreducibles of a lattice.
require 'sarl' # include the create_bn_lattice function given above lattice = create_bn_lattice(5) join_irr = BitSet.new() for c in lattice do if lattice.lower_covers[c].count == 1 then join_irr.set(c) end end
This shows that most relations look like arrays. In fact they are implemented internally as arrays and manifest themselves as such at the ruby layer.