Other programmers and forum members raised suspicions that Robert took ideas from the controversial Ippolit/Robbolito source code too literally as initial base of his program.

Robert Houdart claims his engine is original, and admits taking ideas from the open source programs Ippolit/ Robbolito, Stockfish and Crafty. Houdini 6.03 won the TCEC Season 10 Superfinal versus Komodo 1970.00, a successor of Komodo 11, with 53 - 47 (+15=76-9). Released in September 2017, Houdini 6 again improved in search and evaluation to add another 50-60 Elo in strength, which roughly corresponds to doubling the computational power of the computer. But that was apparently not enough for Stockfish 8 in long time control matches - Houdini 5 lost the 100 game Superfinal with 45½ - 54½. The final release version of Houdini 5 is about 30 Elo stronger than the engine that played in the TCEC tournament so far. Houdini 5 Pro supports up to 128 threads, up to 128 GiB of hash memory, large memory pages, NUMA-architecture, and Nalimov tablebases to find the shortest path to mate.Ī development version of Houdini 5 qualified for TCEC Season 9 Superfinal, and even won the TCEC Season 9 Rapid tournament. It has a completely rewritten evaluation with more aggressive king safety and sophisticated piece mobility, features a more selective search, exploring critical variations significantly deeper, and for hardware with multiple processors, Lazy SMP. Released about three years after the previous version, in November 2016, Houdini 5 is vastly improved being about 200 Elo stronger than Houdini 4. Houdini 4, released in November 2013, was about 50 Elo stronger than its predecessor, and features 6-men Syzygy bases. Since November 2012, Houdini 3 is available as ChessBase engine. If a different move becomes best at very high search depths at the root, re-searches to determine its exact score and the new principal variation are done faster due to a reduced search depth, presumably in conjunction with extensions along the PV. According to its author, Houdini 3 applies a accelerated principal variation search, also dubbed 'Smart' Fail-High. Houdini 3, released in October 2012, has further improved by more than 50 Elo points. Houdini 1.5a remains available as a free download.

Houdini 2, released in September 2011, is commercial and bundled with a number of ChessOK products, such as Aquarium, Chess Assistant, and since December 2011, Chess King. In January 2011, Houdini 1.5 was leading Ingo Bauer's IPON rating list. A chess engine by Robert Houdart, which appeared in 2010 as closed source engine, free for non-commercial use.

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