Module Pentominos.PolyominoSource

A Polyomino is a puzzle piece composed of a number equally sized grid-squares. Depending on the number of squares they can go by different names.

We represent polyominos as a Set of points with an x and y coordinate.

Typically puzzles and games involving polyominos have physical puzzle pieces that can be flipped over and rotated. The pieces can also be placed down on the puzzle board at different locations.

This means that to decide whether two sets of points represent the same Polyomino puzzle piece, we need to consider them equivalent under these transformations:

Sourcetype t

An unplaced polyomino puzzle piece. It is characterized by a normalized PointSet, making it invariant to any combination 90 degree rotation, mirroring, and translation.

Sourceval name : t -> char

Gets the 'name' of a polyomino. The name is unique for polyomino of a the same order (i.e. if two polyominos have the same order and the same name, it means they are the same polyomino)

Sourceval compare : t -> t -> int

Compares two polymoninos to see if they represent the same shape; invariant to rotation, mirroring and translation

Sourceval order : t -> int

The number of squares in a polyomino is called its 'order'.

Sourceval points : t -> PointSet.t

Gets the canonical PointSet that characterizes this Polyomino

Sourceval variants : t -> PointSet.t List.t

Gets all variants of a given Polyomino. A variant is simlar shape obtained by applying rotation and mirroring transformations (but no translation). I.e. it is a specific orientation of Polyomino that has not yet been placed on a specific location of the board.

Sourceval to_string : t -> string

Create a 'string-image' of the polyomino

Sourceval of_order : int -> t list

Obtain all unique polymino of order n

Sourceval pp_poly : Format.formatter -> t -> unit

Print string image of polyomino to a formatter

Sourceval pin_symmetry : t list -> t list

Find the first polyomino that is completely assymetric and remove all but one of its variants. This is a 'hack' that allows eliminating equivalent symmetric solutions from a puzzle.

Sourceval randomize : t list -> t list

Randomize the order of puzzle pieces and their variants. This can make running puzzle solvers more interesting as it then tends to produce different solutions each time you run it.

Sourceval save : out_channel -> t list -> unit

Writes a list of polyominos and all their variants in a textual format that is human readable; but can also be used to restore that same list of pieces and variants by loading the file later.

Sourceval save_fmt : Format.formatter -> t list -> unit

Like save but writes the data to Format.formatter instead of a out_channel

Sourceval load : in_channel -> t list

Reads a list of polyominos and all their variants from a file that was previously written using save

Sourceval load_lines : Knights_tour.Lines.t -> t list

Reads a list of polyominos and all their variants from sequence of lines, as previously written using save