Enos scrabble documentation addendum

Notes on algorithms:

HASHING
=======
The fast hashing (HashOfWords.java) scheme finds words in essentially
constant time: search for bucket is O(1) using bitmapped encoding of
the word (26-bit bitmap converted to a decimal number ranging from
0..2^26-1); search for specific words matching letters in the
combination being examined is linear in a small constant, specifically
the number of words having the same letters as the combination
checked, (irrespective of cardinality), and comparison is again made
numerically, this time using an 8-bit per letter encoding of the
cardinality of specific letters. In this way, we can achieve an average
search time for the next move (in the fast, non-minmax version of the
client) of an average of 150 millliseconds per move on the cs cluster.

EVALUATING COMBINATIONS OF LETTERS
 ==================================
combinations of letters from the hand are selected and order for
search for words using the following heuristic: 

>sum is taken over the total possible bigram frequencies in the
combination
> combination is ranked according to the formula:
exp(bigramSum)* totalLetterScore

This heuristic produced the highest mean word score of heuristics tried.
Running the test suite included will demonstrate thse results.


CLASSES
=======

>src: (root package - no package name enos

EnosScrabbleClient.java
Client class for scrabble server; contains a Game object representing game state. Communicates with Game by passing messages via a Move object.



>src/enos/scrabble/datastruct:
HashOfWords.java
Data structure for dictionary


src/enos/scrabble/domain:
Anchor.java
Enapsulates component of word using letters from the board.

Board.java
Validates moves, finds collateral words made by placing a word on
the board.

Dictionary.java
Ecapsulates hash map, provides for search.

Game.java
Contains entire state of the game; is cloned for use at each node of MiniMax search.

InvalidMoveException.java
Used to signal invalid move.

LetterBonusSquare.java
Encasulates a bonus that multiplies entire Word.

MoveGroup.java
Encapsulates the Move played and any collateral scoring moves created on
the board by the word played.

Move.java
Encapsulates the word  played, its location and score.

PlainSquare.java
Sqaure with no bonus.

Player.java
Encapsulates the heuristics used in choosing potential moves.


Rack.java
Player's current hand. Provides permutations of letters in hand.

Square.java
Superclass for all squares.

WordBonusSquare.java
Bonus that multiplies only its letter.

Word.java
Encapulates the letters of a move, the anchor on the board, the letter
score, and the bigram potentiality of the word.

src/enos/scrabble/test:
Classes that contain unit tests for various domain and datastructure classes


BoardTest.java
HashTest.java
ScrabbleTest.java

src/enos/scrabble/util:
BigramEvaluator.java
Orders words using bigram algorithm described above.

MiniMaximizer.java
MiniMax search.