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Aquarium Engine Matches and Tournaments, Part Two 06 October 2011

After being preempted by the release of Aquarium 2011 for the past two months, we now continue our coverage of engine matches and tournaments in Aquarium.

Observing Games

We finished Part One by having a quick look at the following screen-shot of a chess engine game in progress:


We’ll have a closer look at this window now, starting in the upper-left corner.

There are two tabs at the top of the image. Observe Game is currently active, but Board allows you to set various options related to board display and move input. There are two buttons on the Observe Game tab.







“Stop Game” brings up the following dialog box.


This window has two panes: “Game result” and “Event options.” If you select Abort in the “Game result” pane, the game will be erased and replayed at a later time. Otherwise the game will be adjudicated according to the result you select. The “Event options” pane let’s you decide if play will continue after the current game has been aborted or adjudicated. If you choose “Event will stop,” it can be resumed at a later time.

“Adjudicate” is a simplified version of “Stop Game” and displays the following options. chessok57dThe current game will be finished with the result you chose from the list and after that the next game will start automatically.





The tool button (or dialog box launcher) in the lower right corner of the Observe Game tab opens the “Observe options” dialog shown below.







Automatically invert board turns the board depending on which engine is doing better in the event. You always see the board from the side of the engine with the higher score.

Add “Time” annotations displays the time used for each move in the notation as shown in the following screen-shot.

chessok57gThe annotation after White’s twentieth move, Rfc1, means that the engine evaluation was +0.48, the move was analyzed to depth 12 and because ‘Add “Time” to annotations’ was selected it also shows that the engine spent eight seconds (8s) on that move.

chessok57hThe Navigation Pane is the sidebar on the left hand side of the window, below the Ribbon.

When you are observing a game, “Current game” is highlighted in the sidebar as shown in the image. You can switch back to the list of events either by clicking “Engine games” (above “Current game”) or by clicking “Return to events list” in the Actions pane. You can keep the current game open and switch between the two views as you like.

The Working Area displays the current game and you have the same flexibility as usual in choosing which windows are displayed and how they are arranged. The following image shows an example.

chessok57ichessok57j The board displays the current position. The notation is displayed to the right of the board, but the Clock window is above the notation.

The window is divided into two panes with the left pane showing information about the white side and the right pane showing the black side of the game. The first line shows the name of the engine. The second line shows a colored square indicating which side the engine is playing followed by the clock. In this example, White has two minutes and fifty-one seconds left until the next time control (or end of the game) and Black has three minutes and twenty-two seconds. The red color tells us that it’s Black’s move. The opening book used by the engines is displayed at the bottom of the window. If you don’t see the name of the opening book when observing a game, you can increase the size of the Clock window by dragging its bottom edge downwards. Note that you can place the Clock window anywhere you like by dragging it. Some users may, for instance, prefer to place it above the chessboard.

chessok57kThe Chart window is displayed below the board in the screen-shot above.

By default, the chart shows a bar chart of the engine evaluations after each move. You can select colors and other options by clicking the ellipses button in the lower right corner. The horizontal axis shows the move number and the vertical axis shows the evaluation in pawns. The two sliders near the lower right corner change the scales of the axis. If the chart is too wide for the window, you can change the scale, use the navigation buttons in the lower left corner or simply drag the chart horizontally with the mouse to move it around.

If you do not see the Chart window, you can enable it with the Layout menu at the bottom of the sidebar (the small, black downward pointing triangle).

chessok57lThe Analysis window shows the output from the engines while they are analyzing. This window is split into two panes, similar to the Clock window, with the White’s analysis on the left side and Black’s analysis on the right side. The screen-shot above shows that the content of the panes is almost identical to the Analysis window for infinite analysis.

In addition to the windows described above, the Tree window can also be displayed while observing engine games. It is enabled through the Layout menu mentioned above.

If you switch back to the event list (using one of the methods described above) while a game is being played, you will see a group with three buttons in the Ribbon labeled “Current game.”

chessok57m“Stop Game” and “Adjudicate” work exactly as described above and “Observe” takes you back to the “Current game” view. The Events group looks as follows during a game.


chessok57nIf you click the “Pause” button, the current game will be played out, but then the event will be stopped. If you change your mind after clicking the button, you can click it again to cancel the pause request.

We had a look at the buttons in the second column last month and “Add Engine” will be described later.

The tool button in the lower right corner brings up the “Observe options” described above.

After an event has been stopped, either with the “Stop Game” or “Pause” button, the “Current game” group is removed from the Ribbon and the “Events” group looks as shown in the next image.

chessok57oIf you want to continue an event that has been stopped, you can select it in the “Event list” window and click the “Play” button shown here.



Rybka Randomizer Matches

The idea of a Rybka Randomizer match is to allow a user to play many games from a single starting position in order to collect statistics about that position. A randomized Rybka will keep track of the previous games and not repeat previous variations, so that a match between two randomized Rybkas will systematically explore the space of variations from the starting position. Rybka Randomizer matches are based on the same concept as Rybka Monte Carlo matches. The advantage of a Randomizer match is that you have much more flexibility in specifying match parameters, but it’s slower than Rybka Monte Carlo.

If you want to create a new Randomizer match, select “Rybka Randomizer match” from the “Create New” menu as shown below.

chessok57pThe “Randomizer match properties” will be displayed. It is similar to the normal “Match properties” dialog box, except for one parameter.



chessok57qThe “Search window (centipawns)” parameter is unique for Randomizer matches. It is a centipawn threshold margin for candidate moves. In this example it is set to ten centipawns. You can increase or decrease the breadth of the alternatives that are explored during the play by increasing or decreasing this value. This parameter is only utilized by Rybka and it has no effect on other engines. You can have a randomized Rybka play against a nonrandomized Rybka (or any other engine). The non-randomized engine will of course always choose the best moves, while the randomized Rybka will vary her play in order to cover all of the variations.

A randomized Rybka remembers the previously-played positions from the moment she is loaded to the moment that she is unloaded. If you would like to repeat a previous match from the beginning without attempting to skip already-played variations, you should unload the engine from memory and start a new match.

chessok57rYou have access to all the same settings as in a normal engine match, except that you can’t specify an opening book for the engines.

When a Randomizer match is over you can right-click the match in the event list and select “View all games” or “Build statistics tree” if you want to see the statistics for the various moves played in the match.



Engine Tournaments

Besides engine matches, Aquarium supports three types of engine tournaments: Round robin, Swiss system and Gauntlets. You can create a new tournament using the same methods as described for engine matches in last month’s column: ● Go to Engines mode, select the engines that you want to participate in the tournament and click Start Play. ● Click the Aquarium Button in the upper-left corner of the application window, select Engines from the Aquarium Menu and click “Start engine tournament.” ● Switch to Engine Competitions and select Tournament from the “Create New” menu as shown in the next image. This is the most common method of starting a new tournament.

chessok57sThe Tournament properties dialog box is very similar to the Match properties, so I will only describe the tournament specific properties here. The first step is to select the participants in the tournament.


chessok57tThe Engines pane shows two lists of engines. On the left you see “Playing in tournament,” which lists the engines that have already been added to the tournament. The list on the right, “Available,” shows all other installed engines. You can highlight a single engine with a mouse click or several engines by holding down the Ctrl key while you click. You can also select a range of engines by holding down the Shift key while dragging the mouse. When you have selected one or more engines in the “Available” column you can add them to the tournament by clicking the “< " button between the two lists. You can also drag the engines with the mouse.

If you want to remove an engine from the tournament, you must first highlight it and then click the “>” button. In case you want to remove all the engines from the tournament, just click the “>>” button. Finally, if you want all your installed engines to play in the tournament, you can do so by clicking the “< <" button.

Double-clicking an engine in one of the lists will transfer it to the other list.

If you want to change the order of the engines in the participant list, you can drag them to the correct place with the mouse.

The “Tournament settings” pane let’s you choose from three types of tournaments: Round robin, Swiss system and Gauntlet.

chessok57uIn this example, I have set “Tournament type” to Round robin. Setting “Rounds” to two, means that this will be a double Round robin where each engine must play two games against all other participants. New engines can be added to Round robin tournaments at any time before they are finished.

chessok57vIf you want to add a new engine to an ongoing Round robin tournament, click the “Add Engine” button. A list of available engines will be displayed.



chessok57wSelect an engine from the list and click OK. The engine will be added to the tournament.

Note that Round robin tournaments are automatically marked as finished when the last game has been played. After that you cannot add new engines to the tournament.

You can also add new engines to an active Gauntlet tournament. Gauntlets are never automatically marked as finished, but of course you can finish any tournament manually by clicking the Finish button.

Gauntlets are a special type of tournament where a selected engine plays against all other engines in the tournament. The gauntlet engine is the engine at the top of the list of participants.

chessok57xAfter you have invited the engines to the tournament, simply drag the gauntlet engine to the top of the list. In this example, “Rybka 3 Human w32” will be the gauntlet engine and play against the three other engines in the tournament. The “Rounds” option specifies how many games will be played against each of the engines.

It doesn’t make much sense to add engines to an ongoing Swiss system tournament so it isn’t allowed. The “Rounds” option specifies how many rounds will be played in a Swiss system tournament.


This concludes our coverage of engine matches and tournaments in Aquarium 2011. Though several types of tournaments and matches are supported in Aquarium, the unified and improved dialogs make it easy for new users to get started. Once they have understood how to create and run one type of match or tournament, they will find it easy to understand and run all other types.

Dadi Jonsson

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