Develop generic nested container range, use for strategies (#683)

Extends the nested range developed for information sets to a generic template, and uses it also to iterate the strategies of a game.

Author: tturocy

src/core/array.h

@@ -94,6 +94,7 @@ template <class T> class Array {
   void erase(iterator pos) { m_data.erase(pos); }
   void push_back(const T &value) { m_data.push_back(value); }
   void pop_back() { m_data.pop_back(); }
+  void reserve(size_t len) { m_data.reserve(len); }
 };
 
 /// Convenience function to erase the element at `p_index`

src/core/function.cc

@@ -43,7 +43,7 @@ using namespace Gambit;
 // vector perpendicular to the plane, then subtracting to compute the
 // component parallel to the plane.)
 //
-void FunctionOnSimplices::Project(Vector<double> &x, const Array<int> &lengths) const
+void FunctionOnSimplices::Project(Vector<double> &x, const Array<size_t> &lengths) const
 {
   int index = 1;
   for (size_t part = 1; part <= lengths.size(); part++) {

src/core/function.h

@@ -42,7 +42,7 @@ class FunctionOnSimplices : public Function {
 
 protected:
   // Project the gradient 'x' onto the plane of the product of simplices.
-  void Project(Vector<double> &x, const Array<int> &lengths) const;
+  void Project(Vector<double> &x, const Array<size_t> &lengths) const;
 };
 
 class FunctionMinimizerError : public std::runtime_error {

src/games/game.h

@@ -818,39 +818,6 @@ class GameRep : public std::enable_shared_from_this<GameRep> {
     throw UndefinedException();
   }
 
-  /// @name Dimensions of the game
-  //@{
-  /// The number of strategies for each player
-  virtual Array<int> NumStrategies() const = 0;
-  /// Gets the i'th strategy in the game, numbered globally
-  virtual GameStrategy GetStrategy(int p_index) const = 0;
-  /// Creates a new strategy for the player
-  virtual GameStrategy NewStrategy(const GamePlayer &p_player, const std::string &p_label)
-  {
-    throw UndefinedException();
-  }
-  /// Remove the strategy from the game
-  virtual void DeleteStrategy(const GameStrategy &p_strategy) { throw UndefinedException(); }
-  /// Returns the number of strategy contingencies in the game
-  int NumStrategyContingencies() const
-  {
-    BuildComputedValues();
-    return std::transform_reduce(
-        m_players.begin(), m_players.end(), 0, std::multiplies<>(),
-        [](const std::shared_ptr<GamePlayerRep> &p) { return p->m_strategies.size(); });
-  }
-  /// Returns the total number of actions in the game
-  virtual int BehavProfileLength() const = 0;
-  /// Returns the total number of strategies in the game
-  int MixedProfileLength() const
-  {
-    BuildComputedValues();
-    return std::transform_reduce(
-        m_players.begin(), m_players.end(), 0, std::plus<>(),
-        [](const std::shared_ptr<GamePlayerRep> &p) { return p->m_strategies.size(); });
-  }
-  //@}
-
   virtual PureStrategyProfile NewPureStrategyProfile() const = 0;
   virtual MixedStrategyProfile<double> NewMixedStrategyProfile(double) const = 0;
   virtual MixedStrategyProfile<Rational> NewMixedStrategyProfile(const Rational &) const = 0;
@@ -899,14 +866,48 @@ class GameRep : public std::enable_shared_from_this<GameRep> {
   virtual GamePlayer NewPlayer() = 0;
   //@}
 
+  /// @name Dimensions of the game
+  //@{
+  using Strategies =
+      NestedElementCollection<Game, &GameRep::GetPlayers, &GamePlayerRep::GetStrategies>;
+  /// Returns the set of strategies in the game
+  Strategies GetStrategies() const
+  {
+    BuildComputedValues();
+    return Strategies(std::const_pointer_cast<GameRep>(this->shared_from_this()));
+  }
+  /// Gets the i'th strategy in the game, numbered globally starting from 1
+  GameStrategy GetStrategy(const std::size_t p_index) const
+  {
+    const auto strategies = GetStrategies();
+    if (p_index < 1 || p_index > strategies.size()) {
+      throw std::out_of_range("Strategy index out of range");
+    }
+    return *std::next(strategies.begin(), p_index - 1);
+  }
+  /// Creates a new strategy for the player
+  virtual GameStrategy NewStrategy(const GamePlayer &p_player, const std::string &p_label)
+  {
+    throw UndefinedException();
+  }
+  /// Remove the strategy from the game
+  virtual void DeleteStrategy(const GameStrategy &p_strategy) { throw UndefinedException(); }
+  /// Returns the total number of actions in the game
+  virtual int BehavProfileLength() const = 0;
+  //@}
+
   /// @name Information sets
   //@{
-  class Infosets;
+  using Infosets =
+      NestedElementCollection<Game, &GameRep::GetPlayers, &GamePlayerRep::GetInfosets>;
 
   /// Returns the iset'th information set in the game (numbered globally)
   virtual GameInfoset GetInfoset(int iset) const { throw UndefinedException(); }
   /// Returns the set of information sets in the game
-  virtual Infosets GetInfosets() const;
+  virtual Infosets GetInfosets() const
+  {
+    return Infosets(std::const_pointer_cast<GameRep>(this->shared_from_this()));
+  }
   /// Sort the information sets for each player in a canonical order
   virtual void SortInfosets() {}
   /// Returns the set of actions taken by the infoset's owner before reaching this infoset
@@ -958,83 +959,6 @@ class GameRep : public std::enable_shared_from_this<GameRep> {
   virtual void BuildComputedValues() const {}
 };
 
-class GameRep::Infosets {
-  Players m_players;
-
-public:
-  explicit Infosets(const Players &outer) : m_players(outer) {}
-
-  class iterator {
-    using OuterIter = Players::iterator;
-    using InnerIter = GamePlayerRep::Infosets::iterator;
-
-    OuterIter m_playerIterator, m_playerEnd;
-    InnerIter m_infosetIterator, m_infosetEnd;
-
-    void next()
-    {
-      while (m_playerIterator != m_playerEnd && m_infosetIterator == m_infosetEnd) {
-        ++m_playerIterator;
-        if (m_playerIterator != m_playerEnd) {
-          auto infosets = (*m_playerIterator)->GetInfosets();
-          m_infosetIterator = infosets.begin();
-          m_infosetEnd = infosets.end();
-        }
-      }
-    }
-
-  public:
-    using iterator_category = std::forward_iterator_tag;
-    using value_type = GameInfoset;
-    using reference = GameInfoset;
-    using pointer = GameInfoset;
-    using difference_type = std::ptrdiff_t;
-
-    iterator() = default;
-
-    iterator(const OuterIter &p_playerIterator, const OuterIter &p_playerEnd)
-      : m_playerIterator(p_playerIterator), m_playerEnd(p_playerEnd)
-    {
-      if (m_playerIterator != m_playerEnd) {
-        const auto infosets = (*m_playerIterator)->GetInfosets();
-        m_infosetIterator = infosets.begin();
-        m_infosetEnd = infosets.end();
-      }
-      next();
-    }
-
-    reference operator*() const { return *m_infosetIterator; }
-    pointer operator->() const { return *m_infosetIterator; }
-
-    iterator &operator++()
-    {
-      ++m_infosetIterator;
-      next();
-      return *this;
-    }
-
-    iterator operator++(int)
-    {
-      iterator tmp = *this;
-      ++(*this);
-      return tmp;
-    }
-
-    friend bool operator==(const iterator &a, const iterator &b)
-    {
-      return a.m_playerIterator == b.m_playerIterator &&
-             (a.m_playerIterator == a.m_playerEnd || a.m_infosetIterator == b.m_infosetIterator);
-    }
-
-    friend bool operator!=(const iterator &a, const iterator &b) { return !(a == b); }
-  };
-
-  iterator begin() const { return {m_players.begin(), m_players.end()}; }
-  iterator end() const { return {m_players.end(), m_players.end()}; }
-};
-
-inline GameRep::Infosets GameRep::GetInfosets() const { return Infosets(GetPlayers()); }
-
 //=======================================================================
 //          Inline members of game representation classes
 //=======================================================================

src/games/gameagg.cc

@@ -196,32 +196,6 @@ Game GameAGGRep::Copy() const
   return ReadAggFile(is);
 }
 
-//------------------------------------------------------------------------
-//                  GameAGGRep: Dimensions of the game
-//------------------------------------------------------------------------
-
-Array<int> GameAGGRep::NumStrategies() const
-{
-  Array<int> ns;
-  for (const auto &player : m_players) {
-    ns.push_back(player->GetStrategies().size());
-  }
-  return ns;
-}
-
-GameStrategy GameAGGRep::GetStrategy(int p_index) const
-{
-  for (const auto &player : m_players) {
-    if (static_cast<int>(player->GetStrategies().size()) >= p_index) {
-      return player->GetStrategy(p_index);
-    }
-    else {
-      p_index -= player->GetStrategies().size();
-    }
-  }
-  throw std::out_of_range("Strategy index out of range");
-}
-
 //------------------------------------------------------------------------
 //                    GameAGGRep: Factory functions
 //------------------------------------------------------------------------

src/games/gameagg.h

@@ -46,10 +46,6 @@ class GameAGGRep : public GameRep {
   std::shared_ptr<agg::AGG> GetUnderlyingAGG() const { return aggPtr; }
   /// @name Dimensions of the game
   //@{
-  /// The number of strategies for each player
-  Array<int> NumStrategies() const override;
-  /// Gets the i'th strategy in the game, numbered globally
-  GameStrategy GetStrategy(int p_index) const override;
   /// Returns the total number of actions in the game
   int BehavProfileLength() const override { throw UndefinedException(); }
   //@}

src/games/gamebagg.cc

@@ -99,16 +99,16 @@ template <class T> class BAGGMixedStrategyProfileRep : public MixedStrategyProfi
 template <class T> T BAGGMixedStrategyProfileRep<T>::GetPayoff(int pl) const
 {
   auto &g = dynamic_cast<GameBAGGRep &>(*(this->m_support.GetGame()));
-  std::vector<double> s(g.MixedProfileLength());
-  Array<int> ns = g.NumStrategies();
+  std::vector<double> s(g.GetStrategies().size());
+  const auto ns = g.GetStrategies().shape();
   int bplayer = -1, btype = -1;
   for (int i = 0, offs = 0; i < g.baggPtr->getNumPlayers(); ++i) {
     for (int tp = 0; tp < g.baggPtr->getNumTypes(i); ++tp) {
       if (pl == g.baggPtr->typeOffset[i] + tp + 1) {
         bplayer = i;
         btype = tp;
       }
-      for (int j = 0; j < ns[g.baggPtr->typeOffset[i] + tp + 1]; ++j, ++offs) {
+      for (int j = 0; j < ns[g.baggPtr->typeOffset[i] + tp]; ++j, ++offs) {
         const GameStrategy strategy = this->m_support.GetGame()
                                           ->GetPlayer(g.baggPtr->typeOffset[i] + tp + 1)
                                           ->GetStrategy(j + 1);
@@ -124,7 +124,7 @@ template <class T>
 T BAGGMixedStrategyProfileRep<T>::GetPayoffDeriv(int pl, const GameStrategy &ps) const
 {
   auto &g = dynamic_cast<GameBAGGRep &>(*(this->m_support.GetGame()));
-  std::vector<double> s(g.MixedProfileLength());
+  std::vector<double> s(g.GetStrategies().size());
   int bplayer = -1, btype = -1;
   for (int i = 0; i < g.baggPtr->getNumPlayers(); ++i) {
     for (int tp = 0; tp < g.baggPtr->getNumTypes(i); ++tp) {
@@ -163,7 +163,7 @@ T BAGGMixedStrategyProfileRep<T>::GetPayoffDeriv(int pl, const GameStrategy &ps1
   }
 
   auto &g = dynamic_cast<GameBAGGRep &>(*(this->m_support.GetGame()));
-  std::vector<double> s(g.MixedProfileLength());
+  std::vector<double> s(g.GetStrategies().size());
   int bplayer = -1, btype = -1;
   for (int i = 0; i < g.baggPtr->getNumPlayers(); ++i) {
     for (int tp = 0; tp < g.baggPtr->getNumTypes(i); ++tp) {
@@ -236,15 +236,6 @@ Game GameBAGGRep::Copy() const
 //                 GameBAGGRep: Dimensions of the game
 //------------------------------------------------------------------------
 
-Array<int> GameBAGGRep::NumStrategies() const
-{
-  Array<int> ns;
-  for (const auto &player : m_players) {
-    ns.push_back(player->m_strategies.size());
-  }
-  return ns;
-}
-
 PureStrategyProfile GameBAGGRep::NewPureStrategyProfile() const
 {
   return PureStrategyProfile(std::make_shared<BAGGPureStrategyProfileRep>(

src/games/gamebagg.h

@@ -53,10 +53,6 @@ class GameBAGGRep : public GameRep {
 
   /// @name Dimensions of the game
   //@{
-  /// The number of strategies for each player
-  Array<int> NumStrategies() const override;
-  /// Gets the i'th strategy in the game, numbered globally
-  GameStrategy GetStrategy(int p_index) const override { throw UndefinedException(); }
   /// Returns the total number of actions in the game
   int BehavProfileLength() const override { throw UndefinedException(); }
   //@}

src/games/gameexpl.cc

@@ -54,34 +54,6 @@ Rational GameExplicitRep::GetMaxPayoff() const
                          });
 }
 
-//------------------------------------------------------------------------
-//                GameExplicitRep: Dimensions of the game
-//------------------------------------------------------------------------
-
-Array<int> GameExplicitRep::NumStrategies() const
-{
-  BuildComputedValues();
-  Array<int> dim;
-  for (const auto &player : m_players) {
-    dim.push_back(player->m_strategies.size());
-  }
-  return dim;
-}
-
-GameStrategy GameExplicitRep::GetStrategy(int p_index) const
-{
-  BuildComputedValues();
-  int i = 1;
-  for (const auto &player : m_players) {
-    for (const auto &strategy : player->m_strategies) {
-      if (p_index == i++) {
-        return strategy;
-      }
-    }
-  }
-  throw std::out_of_range("Strategy index out of range");
-}
-
 //------------------------------------------------------------------------
 //                      GameExplicitRep: Outcomes
 //------------------------------------------------------------------------

src/games/gameexpl.h

@@ -39,14 +39,6 @@ class GameExplicitRep : public GameRep {
   Rational GetMaxPayoff() const override;
   //@}
 
-  /// @name Dimensions of the game
-  //@{
-  /// The number of strategies for each player
-  Array<int> NumStrategies() const override;
-  /// Gets the i'th strategy in the game, numbered globally
-  GameStrategy GetStrategy(int p_index) const override;
-  //@}
-
   /// @name Outcomes
   //@{
   /// Creates a new outcome in the game