pub fn run<G: Game>(game: &G) -> G::Turn {
    // Record time MCTS was started
    let now = Instant::now();

    // Create the game tree
    let game = game.clone();
    let mut tree = Tree::new(Box::new(game));
    tree.expand(tree.root); // expand at root

    // Return immediately if only one valid turn
    if tree[tree.root].children.len() == 1 {
        let root = &tree[tree.root];
        return tree[root.children[0]].action.clone().unwrap();
    }

    while now.elapsed().as_millis() < DURATION {
        // Select a leaf node to expand
        let mut leaf = tree.select();

        // Expand `leaf` if it's been simulated more than `THRESHOLD`
        if tree[leaf].sims > THRESHOLD {
            tree.expand(leaf);
            leaf = *tree[leaf]
                .children
                .choose(&mut rand::thread_rng())
                .unwrap_or(&leaf);
        }

        // Simulate at `leaf`
        let winner = tree[leaf].simulate();

        // Backpropagate the winner
        tree.backprop(leaf, winner);
    }

    // Find most simulated node
    let root = &tree[tree.root];
    debug!("idx: sims, wins%, priority");
    let best = &tree[*root
        .children
        .iter()
        .map(|idx| (idx, &tree[*idx]))
        .inspect(|(idx, node)| {
            debug!(
                "{:03}: {:4}, {:4.1}%, {:.6}",
                idx,
                node.sims,
                100. * (node.wins as f64) / (node.sims as f64),
                node.priority(tree[node.parent].sims),
            )
        })
        .max_by(|(_, a), (_, b)| a.sims.partial_cmp(&b.sims).unwrap_or(Ordering::Equal))
        .unwrap()
        .0];

    // Play most simulated node
    best.action.clone().unwrap()
}
/// Run MCTS to select a turn.
Run MCTS to select a turn.
Run MCTS to select a turn .
pub fn run<G: Game>(game: &G) -> G::Turn {
    // Record time MCTS was started
    let now = Instant::now();
    // Create the game tree
    let game = game.clone();
    let mut tree = Tree::new(Box::new(game));
    tree.expand(tree.root); // expand at root
    // Return immediately if only one valid turn
    if tree[tree.root].children.len() == 1 {
        let root = &tree[tree.root];
        return tree[root.children[0]].action.clone().unwrap();
    }
    while now.elapsed().as_millis() < DURATION {
        // Select a leaf node to expand
        let mut leaf = tree.select();
        // Expand `leaf` if it's been simulated more than `THRESHOLD`
        if tree[leaf].sims > THRESHOLD {
            tree.expand(leaf);
            leaf = *tree[leaf]
                .children
                .choose(&mut rand::thread_rng())
                .unwrap_or(&leaf);
        }
        // Simulate at `leaf`
        let winner = tree[leaf].simulate();
        // Backpropagate the winner
        tree.backprop(leaf, winner);
    }
    // Find most simulated node
    let root = &tree[tree.root];
    debug!("idx: sims, wins%, priority");
    let best = &tree[*root
        .children
        .iter()
        .map(|idx| (idx, &tree[*idx]))
        .inspect(|(idx, node)| {
            debug!(
                "{:03}: {:4}, {:4.1}%, {:.6}",
                idx,
                node.sims,
                100. * (node.wins as f64) / (node.sims as f64),
                node.priority(tree[node.parent].sims),
            )
        })
        .max_by(|(_, a), (_, b)| a.sims.partial_cmp(&b.sims).unwrap_or(Ordering::Equal))
        .unwrap()
        .0];
    // Play most simulated node
    best.action.clone().unwrap()
}
pub fn run < G : Game > ( game : & G ) -> G :: Turn { // Record time MCTS was started let now = Instant :: now ( ) ; // Create the game tree let game = game . clone ( ) ; let mut tree = Tree :: new ( Box :: new ( game ) ) ; tree . expand ( tree . root ) ; // expand at root // Return immediately if only one valid turn if tree [ tree . root ] . children . len ( ) == 1 { let root = & tree [ tree . root ] ; return tree [ root . children [ 0 ] ] . action . clone ( ) . unwrap ( ) ; } while now . elapsed ( ) . as_millis ( ) < DURATION { // Select a leaf node to expand let mut leaf = tree . select ( ) ; // Expand `leaf` if it's been simulated more than `THRESHOLD` if tree [ leaf ] . sims > THRESHOLD { tree . expand ( leaf ) ; leaf = * tree [ leaf ] . children . choose ( & mut rand :: thread_rng ( ) ) . unwrap_or ( & leaf ) ; } // Simulate at `leaf` let winner = tree [ leaf ] . simulate ( ) ; // Backpropagate the winner tree . backprop ( leaf , winner ) ; } // Find most simulated node let root = & tree [ tree . root ] ; debug ! ( " " ) ; let best = & tree [ * root . children . iter ( ) . map ( | idx | ( idx , & tree [ * idx ] ) ) . inspect ( | ( idx , node ) | { debug ! ( " " idx node sims 100. ( node wins as f64 ) ( node sims as f64 ) node priority ( tree [ node parent ] sims ) ) } ) . max_by ( | ( _ , a ) , ( _ , b ) | a . sims . partial_cmp ( & b . sims ) . unwrap_or ( Ordering :: Equal ) ) . unwrap ( ) . 0 ] ; // Play most simulated node best . action . clone ( ) . unwrap ( ) }
Run MCTS to select a turn.
Run MCTS to select a turn .
game
&G
game
&G