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libCSP++ is a small library whose purpose is allowing the programmer who has to
manage constraint-related problems (CSP == Constraint Satisfaction Problem), in
artificial intelligence or any other application, to do it easily, just caring
about how to express the constraints of his own problem, not how to write an
algorithm that verifies those constraints. The programmer only has to focus
three parameters: the variables of the problem (e.g., in a sudoku resolution 
algorithm, each cell of the game may represent a variable), the domains of these
variables (e.g., in a sudoku, each cell may assume values from 1 to 9) and the
constraints of the problem, simply provided like one or more boolean functions
(always in a sudoku, the constraints are represented by a boolean function
returning true if all the variables in the same row, column and cell have
different values, false otherwise). Once focused these features, the programmer
just has to provide them to build a CSP object, without caring of the algorithm
to check the satisfiability of his problem, and so pay his attention to *HIS*
own algorithm.


INSTALLATION:

Just type make install. The files will be copied, by default, to /usr/local.
Change the Makefile if you want them in a different location. No additional
dependency is required. Only a C++ compiler.


USAGE:

Just include <csp++/csp++.h> in your source files using libCSP++, possibly
adding the directory where csp++ directory is located to your include list (for
example, using g++ and supposing you installed csp++ to /usr/local, you would
append -I/usr/local/include to your compiler command line).


DOCUMENTATION:

You can find doxygen-generated documentation, both in HTML and LaTeX format, in
the doc/ directory of the project. If you modify some of the sources files of
the library and want to change the documentation, just move to csp++ directory
and launch `doxygen' command again.


EXAMPLES:

Two examples of usage of the library are provided.

- fourcolours.cpp is a simple application whose purpose is to interactively ask the
user to enter the colours for some European countries. The constraint is that two
adjacent countries on the map cannot have the same colour, and the domain of
each variable (country) is the set of colours it can assume (a set of 4 colours
is used, it has been proved in the chromatic theory of graphs that 4 colours are
enough for satisfying the constraint "two adjacent countries must always have
different colours"). Every time the user inserts the colour for a country, the
domains (colours) of the remaining countries are computed again applying the
constraint just entered by the user, and for the next countries the choice of
the colours is only restricted to these computed domains. If the user has to
choose a colour for a country having an only value left in its domain, that
value will be chosen automatically.

- sudoku.cpp is a nice program that automatically solves a sudoku, theoretically by
any size (in truth the complexity of the algorithm rises exponentially when the
size of the sudoku grows, and the required time for the algorithm is also
inversely proportional to the number of variables already set by default in the
game). The sudoku to be solved is read by a text file. If no file is provided,
the program reads the sudoku contained in ./sudoku.txt. More examples are
provided in files sudoku-easy.txt, sudoku-medium.txt, sudoku-hard.txt and
sudoku-2x2x2.txt. If you want to solve a sudoku different by the one provided in
sudoku.txt, just put the new sudoku in a file whose structure is similar to the
one illustrated in the sample files, and pass it as parameter for the
application (e.g. ./sudoku mysudoku.txt). The application will verify whether
the given game has a solution (unique), is indeterminate (the given variables
are not enough for reaching a unique solution) or impossible (any configuration
leads to a violation of the constraints).

For building the examples, from the root directory of the project just type
`make examples'. For removing them, type `make examples-clean'. For building
only one of them, type `make fourcolours' or `make sudoku', and specularly `make
fourcolours-clean' or `make sudoku-clean'.


LICENCE:

All the source code and examples are released under GNU GPL 3 licence.


AUTHOR:

BlackLight, <blacklight[AT]autistici[DOT]org>, http://0x00.ath.cx