Question

When I build the PlayN project and run the java version, it s behaviour is different to when I run the HTML version.

Basically I made a board game that uses a modified version of the Minimax algorithm (search tree and weighting evaluation) for its AI.

Since nothing is calculated randomly, and if the inputs are the same, I d expect the outputs to be the same too.

However, the AI s of the java and javascript (HTML) versions behave differently to the same input.

The link to the Html/javascript version can be found here: http://mugle-app.appspot.com/+games/staff/fiar/

The java (JAR) file can be found at: http://ez-playn.googlecode.com/files/FiarJava.zip

They both use the same code, only compilations have been different, but both using the provided Ant scripts. Tree depth is fixed, evaluator weightings are fixed

I can t understand why there would be a difference since every thing works except the search tree...could it be because that evaluation is heavy and javascript run s out of resources?

Thanks for any help.

Answer 1

It looks like you are iterating over the contents of a HashMap. Board defines emptyCells which is a HashMap, and then GameSearch calls Board.getEmptyCellCollection (which returns the values of the HashMap as a collection) and then iterates over them. Those values do not have a predictable ordering, and the ordering will almost certainly change in the conversion from Java to JavaScript.

If you need to iterate over the contents of a HashMap in predictable order, use LinkedHashMap.

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