Grcov report - variability_parity

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//! Authors: Maurice Laveaux and Sjef van Loo

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use std::fmt;

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use delegate::delegate;

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use oxidd::BooleanFunction;

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use oxidd::ManagerRef;

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use oxidd::bdd::BDDFunction;

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use oxidd::bdd::BDDManagerRef;

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use merc_symbolic::FormatConfigSet;

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use merc_utilities::MercError;

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use crate::PG;

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use crate::ParityGame;

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use crate::Player;

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use crate::Priority;

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use crate::VertexIndex;

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use crate::minus;

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/// A variability parity game is an extension of a parity game where each edge is

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/// associated with a BDD function representing the configurations in which the

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/// edge is enabled.

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///

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/// # Details

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///

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/// This is also a max-priority parity game. There is also a configuration set associated

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/// with the variability parity game, representing the overall configurations.

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pub struct VariabilityParityGame {

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    /// The underlying normal parity game.

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    game: ParityGame,

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    /// The overall configurations for the variability parity game.

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    configuration: BDDFunction,

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    /// The variables used in the configuration BDD.

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    variables: Vec<BDDFunction>,

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    /// Every edge has an associated BDD function representing the configurations

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    /// in which the edge is enabled.

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    edges_configuration: Vec<BDDFunction>,

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/// Represents an edge in the parity game along with its configuration BDD.

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pub struct Edge<'a> {

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    to: VertexIndex,

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    configuration: &'a BDDFunction,

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impl<'a> Edge<'a> {

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    /// Returns the target vertex of the edge.

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    pub fn to(&self) -> VertexIndex {

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        self.to

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    /// Returns the configuration BDD associated with the edge.

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    pub fn configuration(&self) -> &BDDFunction {

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        self.configuration

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impl VariabilityParityGame {

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    /// Construct a new variability parity game from an iterator over edges.

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    pub fn new(

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        parity_game: ParityGame,

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        configuration: BDDFunction,

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        variables: Vec<BDDFunction>,

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        edges_configuration: Vec<BDDFunction>,

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    ) -> Self {

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        // Check that the sizes are consistent

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        debug_assert_eq!(

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            edges_configuration.len(),

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            parity_game.num_of_edges(),

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            "There should be a configuration BDD for every edge"

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);

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        Self {

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            game: parity_game,

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            configuration,

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            variables,

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            edges_configuration,

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    /// Constructs a new variability parity game from an iterator over edges.

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///

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    /// The vertices are given by their owner and priority.

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    /// The `edges` iterator should yield tuples of the form (from, configuration, to).

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    pub fn from_edges<F, I>(

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        manager_ref: &BDDManagerRef,

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        initial_vertex: VertexIndex,

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        owner: Vec<Player>,

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        priority: Vec<Priority>,

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        configuration: BDDFunction,

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        variables: Vec<BDDFunction>,

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        mut edges: F,

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    ) -> Self

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    where

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        F: FnMut() -> I,

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        I: Iterator<Item = (VertexIndex, BDDFunction, VertexIndex)>,

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        let num_of_vertices = owner.len();

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        debug_assert_eq!(

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            priority.len(),

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            num_of_vertices,

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            "Owner and priority vectors should have the same length"

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);

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        let mut vertices = Vec::new();

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        vertices.resize_with(num_of_vertices, Default::default);

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        debug_assert!(

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            initial_vertex.value() < num_of_vertices,

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            "Initial vertex index {} out of bounds {num_of_vertices}",

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            initial_vertex.value()

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);

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        // Count the number of transitions for every state

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        let mut num_of_edges = 0;

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        for (from, _, to) in edges() {

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            // Ensure that the states vector is large enough.

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            if vertices.len() <= *from.max(to) {

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                vertices.resize_with(*from.max(to) + 1, || 0);

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            vertices[*from] += 1;

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            num_of_edges += 1;

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            debug_assert!(

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                *from < num_of_vertices && *to < num_of_vertices,

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                "Vertex index out of bounds: from {:?}, to {:?}, num_of_vertices {}",

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                from,

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to,

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                num_of_vertices

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);

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        if initial_vertex.value() >= vertices.len() {

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            // Ensure that the initial state is a valid state (and all states before it exist).

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            vertices.resize_with(initial_vertex.value() + 1, Default::default);

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        // Sets the offset for every state into the edge arrays.

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        vertices.iter_mut().fold(0, |count, start| {

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            let result = count + *start;

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            *start = count;

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            result

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});

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        // Place the transitions, and increment the end for every state.

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        let mut edges_to = vec![VertexIndex::new(0); num_of_edges];

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        let mut edges_configuration =

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            manager_ref.with_manager_shared(|manager| vec![BDDFunction::f(manager); num_of_edges]);

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        for (from, config, to) in edges() {

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            let start = &mut vertices[*from];

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            edges_to[*start] = to;

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            edges_configuration[*start] = config;

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            *start += 1;

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        // Reset the offset to the start.

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        vertices.iter_mut().fold(0, |previous, start| {

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            let result = *start;

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            *start = previous;

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            result

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});

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        vertices.push(num_of_edges); // Sentinel vertex

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        Self {

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            game: ParityGame::new(initial_vertex, owner, priority, vertices, edges_to),

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            configuration,

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            variables,

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            edges_configuration,

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    /// Returns an iterator over the outgoing edges of the given vertex.

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    pub fn outgoing_conf_edges(&self, state_index: VertexIndex) -> impl Iterator<Item = Edge<'_>> + '_ {

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        let start = self.game.vertices()[*state_index];

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        let end = self.game.vertices()[*state_index + 1];

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        self.edges_configuration[start..end]

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            .iter()

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            .zip(self.game.edges_to()[start..end].iter())

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            .map(|(configuration, &to)| Edge { to, configuration })

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    /// Returns true iff the parity game is total, checks all vertices have at least one outgoing edge.

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    pub fn is_total(&self, manager_ref: &BDDManagerRef) -> Result<bool, MercError> {

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        // Check that every vertex has at least one outgoing edge.

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        for v in self.iter_vertices() {

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            if self.outgoing_edges(v).next().is_none() {

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                return Ok(false);

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        // Check that the configurations of the outgoing edges cover the overall configuration.

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        for v in self.iter_vertices() {

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            // Compute the disjunction of all outgoing edge configurations.

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            let covered = self.outgoing_conf_edges(v).try_fold(

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                manager_ref.with_manager_shared(|manager| BooleanFunction::f(manager)),

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                |acc: BDDFunction, edge| acc.or(edge.configuration()),

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)?;

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            // If there are configurations not covered by the outgoing edges, the game is not total.

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            if minus(&self.configuration, &covered)?.satisfiable() {

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                return Ok(false);

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        Ok(true)

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    /// Returns the overall configuration BDD of the variability parity game.

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    pub fn configuration(&self) -> &BDDFunction {

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        &self.configuration

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    /// Returns the variables used in the configuration BDD.

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    pub fn variables(&self) -> &Vec<BDDFunction> {

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        &self.variables

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    /// Returns the owners of the vertices in the variability parity game.

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    pub(crate) fn owners(&self) -> &Vec<Player> {

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        self.game.owners()

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    /// Returns the priorities of the vertices in the variability parity game.

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    pub(crate) fn priorities(&self) -> &Vec<Priority> {

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        self.game.priorities()

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impl PG for VariabilityParityGame {

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    delegate! {

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        to self.game {

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            fn initial_vertex(&self) -> VertexIndex;

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            fn num_of_vertices(&self) -> usize;

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            fn num_of_edges(&self) -> usize;

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            fn iter_vertices(&self) -> impl Iterator<Item = VertexIndex> + '_;

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            fn owner(&self, vertex: VertexIndex) -> Player;

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            fn priority(&self, vertex: VertexIndex) -> Priority;

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            fn outgoing_edges(&self, state_index: VertexIndex) -> impl Iterator<Item = VertexIndex> + '_;

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impl fmt::Display for VariabilityParityGame {

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    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {

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        writeln!(f, "Variability Parity Game:")?;

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        writeln!(f, "Configuration BDD: {}", FormatConfigSet(self.configuration()))?;

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        for v in self.iter_vertices() {

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            write!(

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f,

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                "v{}: {:?}, priority={}, edges=[",

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v,

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                self.owner(v).to_index(),

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                self.priority(v)

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)?;

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            let mut first = true;

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            for edge in self.outgoing_conf_edges(v) {

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                if !first {

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                    write!(f, ", ")?;

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                write!(f, "(v{}, {})", edge.to(), FormatConfigSet(edge.configuration()))?;

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                first = false;

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            writeln!(f, "]")?;

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        Ok(())

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