Source: http://www.paulsenzee.com/2007/01/7.html
- Card Representation: 52 bits :
AKQJT98765432repeated 4 times, once per suit. - Hand Representation: 52 bits : 7 cards OR'd together.
- Hand Value: ---same as CactusKev
This is another evaluator that tries to do a direct loopup into a big table. It represents the hand as a 52 bit number with exactly 7 bits set. It provides a hash function index52c7 which turns that into a unique value between 1 and ~133 million. The hash function is hard to reverse-engineer: It splits the input into 16 bit words, then does a series of table lookups, additions and multiplications to get the result. The tables used include a 2^16 entry _bitcount, a 2^16 entry partial result, and a set of smaller offset and multiplier tables.
The final result is now used as an index into a 133 million (265GB) table which contains the Cactus Kev equivalency class. This is actually faster than the two-plus-two evaluator, (likely because it only does 1 lookup in the giant table instead of 7), but it is still slower than most of the less massive evaluators.
*TODO: figure out why 133 million and not 183 million.