In the beginning, Swordfish was my main engine that I wanted to create, to make Stockfish a more tactical engine at a small cost of losing a few Elo's. The much more aggressive but also weaker Blue Marlin was a side project made for fun. Over time, however, Stockfish's progress was so great that despite the very aggressive settings in Blue Marlin, this engine was strong enough to play with a strength similar to Stockfish. Then Blue Marlin became my main project and work on Swordfish was paused mainly because the newer changes made the engine lose its aggressive nature.
At the moment, Stockfish progress is slow despite many patches, and testing if the changes are good for Blue Marlin is quite difficult and time consuming because of many differences between the engines. I'm thinking of stopping development and going back to Swordfish. Swordfish based on the latest Stockfish would be easier to test, but will not be as interesting as Blue Marlin.
Poll about Blue Marlin/Swordfish future
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