Refactor out iteration from contingencies concept

gambitproject · Nov 7, 2024 · b25072b · b25072b
1 parent 373b652
commit b25072b
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Showing 4 changed files with 73 additions and 38 deletions.
diff --git a/src/games/behavpure.cc b/src/games/behavpure.cc
@@ -114,39 +114,54 @@ MixedBehaviorProfile<Rational> PureBehaviorProfile::ToMixedBehaviorProfile() con
 //========================================================================
 
 BehaviorContingencies::BehaviorContingencies(const BehaviorSupportProfile &p_support,
-                                             const std::list<GameAction> &p_frozen)
-  : m_atEnd(false), m_support(p_support), m_profile(p_support.GetGame()), m_frozen(p_frozen)
+                                             const std::vector<GameAction> &p_frozen)
+  : m_support(p_support), m_frozen(p_frozen)
 {
   for (auto player : m_support.GetGame()->GetPlayers()) {
     for (auto infoset : player->GetInfosets()) {
-      m_currentBehav[infoset] = 1;
-      m_profile.SetAction(infoset->GetActions().front());
       if (p_support.IsReachable(infoset)) {
         m_activeInfosets.push_back(infoset);
       }
     }
   }
-
   for (auto action : m_frozen) {
-    m_currentBehav[action->GetInfoset()] = p_support.GetIndex(action);
-    m_profile.SetAction(action);
     m_activeInfosets.erase(std::find_if(
         m_activeInfosets.begin(), m_activeInfosets.end(),
         [action](const GameInfoset &infoset) { return infoset == action->GetInfoset(); }));
   }
 }
 
-void BehaviorContingencies::operator++()
+BehaviorContingencies::iterator::iterator(BehaviorContingencies *p_cont, bool p_end)
+  : m_atEnd(p_end), m_cont(p_cont), m_profile(p_cont->m_support.GetGame())
+{
+  if (m_atEnd) {
+    return;
+  }
+  for (auto player : m_cont->m_support.GetGame()->GetPlayers()) {
+    for (auto infoset : player->GetInfosets()) {
+      m_currentBehav[infoset] = 1;
+      m_profile.SetAction(infoset->GetActions().front());
+    }
+  }
+  for (auto action : m_cont->m_frozen) {
+    m_currentBehav[action->GetInfoset()] = m_cont->m_support.GetIndex(action);
+    m_profile.SetAction(action);
+  }
+}
+
+BehaviorContingencies::iterator &BehaviorContingencies::iterator::operator++()
 {
-  for (auto infoset = m_activeInfosets.crbegin(); infoset != m_activeInfosets.crend(); ++infoset) {
-    if (m_currentBehav.at(*infoset) < m_support.NumActions(*infoset)) {
-      m_profile.SetAction(m_support.GetActions(*infoset)[++m_currentBehav[*infoset]]);
-      return;
+  for (auto infoset = m_cont->m_activeInfosets.crbegin();
+       infoset != m_cont->m_activeInfosets.crend(); ++infoset) {
+    if (m_currentBehav.at(*infoset) < m_cont->m_support.NumActions(*infoset)) {
+      m_profile.SetAction(m_cont->m_support.GetActions(*infoset)[++m_currentBehav[*infoset]]);
+      return *this;
     }
     m_currentBehav[*infoset] = 1;
-    m_profile.SetAction(m_support.GetActions(*infoset).front());
+    m_profile.SetAction(m_cont->m_support.GetActions(*infoset).front());
   }
   m_atEnd = true;
+  return *this;
 }
 
 } // end namespace Gambit
diff --git a/src/games/behavpure.h b/src/games/behavpure.h
@@ -40,6 +40,12 @@ class PureBehaviorProfile {
   //@{
   /// Construct a new behavior profile on the specified game
   explicit PureBehaviorProfile(Game);
+  //@}
+
+  bool operator==(const PureBehaviorProfile &p_other) const
+  {
+    return m_profile == p_other.m_profile;
+  }
 
   /// @name Data access and manipulation
   //@{
@@ -81,31 +87,46 @@ template <> inline std::string PureBehaviorProfile::GetPayoff(const GamePlayer &
 
 class BehaviorContingencies {
 private:
-  bool m_atEnd;
   BehaviorSupportProfile m_support;
-  std::map<GameInfoset, int> m_currentBehav;
-  PureBehaviorProfile m_profile;
-  std::list<GameAction> m_frozen;
+  std::vector<GameAction> m_frozen;
   std::list<GameInfoset> m_activeInfosets;
 
 public:
+  class iterator {
+  private:
+    BehaviorContingencies *m_cont;
+    bool m_atEnd;
+    std::map<GameInfoset, int> m_currentBehav;
+    PureBehaviorProfile m_profile;
+
+  public:
+    iterator(BehaviorContingencies *, bool p_end);
+
+    iterator &operator++();
+
+    bool operator==(const iterator &p_other) const
+    {
+      if (m_atEnd && p_other.m_atEnd && m_cont == p_other.m_cont) {
+        return true;
+      }
+      if (m_atEnd != p_other.m_atEnd || m_cont != p_other.m_cont) {
+        return false;
+      }
+      return (m_profile == p_other.m_profile);
+    }
+    bool operator!=(const iterator &p_other) const { return !(*this == p_other); }
+
+    PureBehaviorProfile &operator*() { return m_profile; }
+    const PureBehaviorProfile &operator*() const { return m_profile; }
+  };
   /// @name Lifecycle
   //@{
-  /// Construct a new iterator on the support, holding the action fixed
-  BehaviorContingencies(const BehaviorSupportProfile &, const std::list<GameAction> & = {});
-  //@}
-
-  /// @name Iteration and data access
-  //@{
-  /// Advance to the next contingency (prefix version)
-  void operator++();
-  /// Advance to the next contingency (postfix version)
-  void operator++(int) { ++(*this); }
-  /// Has iterator gone past the end?
-  bool AtEnd() const { return m_atEnd; }
-  /// Get the current behavior profile
-  const PureBehaviorProfile &operator*() const { return m_profile; }
+  /// Construct a new iterator on the support, holding the listed actions fixed
+  explicit BehaviorContingencies(const BehaviorSupportProfile &,
+                                 const std::vector<GameAction> &p_frozen = {});
   //@}
+  iterator begin() { return {this, false}; }
+  iterator end() { return {this, true}; }
 };
 
 } // end namespace Gambit

diff --git a/src/games/behavspt.cc b/src/games/behavspt.cc
@@ -309,9 +309,9 @@ bool BehaviorSupportProfile::Dominates(const GameAction &a, const GameAction &b,
   bool equal = true;
 
   if (!p_conditional) {
-    for (BehaviorContingencies iter(*this, {a}); !iter.AtEnd(); iter++) {
-      auto ap = (*iter).GetPayoff<Rational>(a);
-      auto bp = (*iter).GetPayoff<Rational>(b);
+    for (auto iter : BehaviorContingencies(*this, {a})) {
+      auto ap = iter.GetPayoff<Rational>(a);
+      auto bp = iter.GetPayoff<Rational>(b);
 
       if (p_strict) {
         if (ap <= bp) {

diff --git a/src/solvers/enumpure/enumpure.h b/src/solvers/enumpure/enumpure.h
@@ -89,10 +89,9 @@ inline List<MixedBehaviorProfile<Rational>> EnumPureAgentSolver::Solve(const Gam
 {
   List<MixedBehaviorProfile<Rational>> solutions;
   BehaviorSupportProfile support(p_game);
-  for (auto citer = BehaviorContingencies(BehaviorSupportProfile(p_game)); !citer.AtEnd();
-       citer++) {
-    if ((*citer).IsAgentNash()) {
-      MixedBehaviorProfile<Rational> profile = (*citer).ToMixedBehaviorProfile();
+  for (auto citer : BehaviorContingencies(BehaviorSupportProfile(p_game))) {
+    if (citer.IsAgentNash()) {
+      MixedBehaviorProfile<Rational> profile = citer.ToMixedBehaviorProfile();
       m_onEquilibrium->Render(profile);
       solutions.push_back(profile);
     }