8.4 Memory-Enhanced Test Algorithms 697 Most commercial board game programs use the opponent's thinking time to do additional searching and store results in memory. 8.4 Memory-Enhanced Test Algorithms Memory-enhanced test (MT) algorithms rely on the existence of an efficient transposition table to act as the algorithms' memory. The MT is simply a zero-width AB negamax, using a transposition table to avoid duplicate work. The existence of the memory allows the algorithm to jump around the search tree looking at the most promising moves first. The recursive nature of the negamax algorithm means that it cannot jump; it must bubble up and recurse down. 8.4.1 Implementing Test Because the window size for Test is always zero, the test is often rewritten to accept only one input value (the A and B values are the same). We'll call this value "gamma." The same test was used in the negamax algorithm, but in that case the negamax algorithm was calling itself as a test and as a regular negamax, so separate alpha and beta parameters were