Are you mobile, picoEngine?

firstMove

With so many of my posts being about mobile phones, this title might seem misleading. However, I am not implying that picoEngine is on a mobile phone, but rather that I have added the ability for it to determine the mobility of the pieces on the board.

So far, picoEngine is off to a good start, since it now believes that the best first move you can make is that of e4, or the kings pawn to the fourth rank. This is great because it is taking into account the fact that such a move would allow it to be more active with it’s pieces. With one move it adds multiple options to it’s repertoire of available moves for the next turn. Here’s a look at the code:

	// Mobility evaluation
	string listMoves ="";
	int deltaChange = 0;
	try {
	listMoves = moveEvaluations.available(thatBoard, true, false, false);
		if (listMoves.size() == 0){
			deltaChange -= 10000; } else {
			deltaChange = deltaChange + listMoves.size()/5;
		}
	listMoves = moveEvaluations.available(thatBoard, false, false, false);
		if (listMoves.size() == 0){
			deltaChange += 10000; } else {
			deltaChange = deltaChange - listMoves.size()/5;
		}
	} catch (...) {
			cout << " Exception " << endl;
			} // End try/catch block
			//cout << deltaChange << " Delta " << endl;
	picoEval += deltaChange;

Pretty straight forward. Essentially, it checks both sides to see how many legal moves they are able to make, and adds a point for each white move, and minuses a point for each black move, creating a mobility delta. This delta, positive or negative, is added to the picoEval variable for final consideration. You can always check out the full commit if you’d like.

I wrapped it in a try/catch block to be safe, but I don’t think that I actually need it in this case. I may remove that later. The best part about this is the null move return. E.g., if no moves are returned, then the opponent must be in stalemate or check mate. This is highly desirable, and hopefully will allow picoEngine to choose moves that lead to a win. We’ll have to play it out and see.

Linux – keep it simple.

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