com.fluxchess.pulse.Perft Maven / Gradle / Ivy

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/*
 * Copyright (C) 2013-2019 Phokham Nonava
 *
 * Use of this source code is governed by the MIT license that can be
 * found in the LICENSE file.
 */
package com.fluxchess.pulse;

import static com.fluxchess.pulse.Color.opposite;
import static com.fluxchess.pulse.MoveList.MoveEntry;
import static java.lang.System.currentTimeMillis;
import static java.util.concurrent.TimeUnit.*;

public final class Perft {

	private static final int MAX_DEPTH = 6;

	private final MoveGenerator[] moveGenerators = new MoveGenerator[MAX_DEPTH];

	public void run() {
		Position position = Notation.toPosition(Notation.STANDARDPOSITION);
		int depth = MAX_DEPTH;

		for (int i = 0; i < MAX_DEPTH; i++) {
			moveGenerators[i] = new MoveGenerator();
		}

		System.out.format("Testing %s at depth %d%n", Notation.fromPosition(position), depth);

		long startTime = currentTimeMillis();
		long result = miniMax(depth, position, 0);
		long endTime = currentTimeMillis();

		long duration = endTime - startTime;

		System.out.format(
				"Nodes: %d%nDuration: %02d:%02d:%02d.%03d%n",
				result,
				MILLISECONDS.toHours(duration),
				MILLISECONDS.toMinutes(duration) - HOURS.toMinutes(MILLISECONDS.toHours(duration)),
				MILLISECONDS.toSeconds(duration) - MINUTES.toSeconds(MILLISECONDS.toMinutes(duration)),
				duration - SECONDS.toMillis(MILLISECONDS.toSeconds(duration))
		);

		System.out.format("n/ms: %d%n", result / duration);
	}

	private long miniMax(int depth, Position position, int ply) {
		if (depth == 0) {
			return 1;
		}

		int totalNodes = 0;

		boolean isCheck = position.isCheck();
		MoveGenerator moveGenerator = moveGenerators[ply];
		MoveList moves = moveGenerator.getMoves(position, depth, isCheck);
		for (int i = 0; i < moves.size; i++) {
			int move = moves.entries[i].move;

			position.makeMove(move);
			if (!position.isCheck(opposite(position.activeColor))) {
				totalNodes += miniMax(depth - 1, position, ply + 1);
			}
			position.undoMove(move);
		}

		return totalNodes;
	}
}