From a9de4273bf8377aeab7d3f76a6d8bc0c89b42f79 Mon Sep 17 00:00:00 2001
From: Carlo Zancanaro <carlo@carlo-laptop>
Date: Fri, 20 Apr 2012 01:19:54 +1000
Subject: Start on the max-strategy stuff. Also more BF.

---
 impl/EquationSystem.hpp | 64 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)
 create mode 100644 impl/EquationSystem.hpp

(limited to 'impl/EquationSystem.hpp')

diff --git a/impl/EquationSystem.hpp b/impl/EquationSystem.hpp
new file mode 100644
index 0000000..efd34b3
--- /dev/null
+++ b/impl/EquationSystem.hpp
@@ -0,0 +1,64 @@
+#ifndef EQUATION_SYSTEM_H
+#define EQUATION_SYSTEM_H
+
+#include <map>
+#include <string>
+#include "Expression.hpp"
+
+template<typename T>
+struct EquationSystem {
+  void add(std::string k, Expression<T> v) {
+    equations.insert(std::pair<std::string, Expression<T> >(k, v));
+  }
+  /**
+     init is the value where it STARTS, it's working the other way
+     if there's no stability then it ends with -init
+  */
+  std::map<std::string, T> solveBF(const T& init) const {
+    std::map<std::string, T> solutions;
+    for (typename std::map<std::string, Expression<T> >::const_iterator it = equations.begin();
+         it != equations.end();
+         ++it){
+      solutions[it->first] = init;
+    }
+    int num = equations.size();
+    for (int i = 0; i < num; ++i) {
+      solutions = eval(solutions, false, -init);
+    }
+    solutions = eval(solutions, true, -init);
+    for (int i = 0; i < num-1; ++i) {
+      solutions = eval(solutions, false, -init);
+    }
+    return solutions;
+  }
+
+  EquationSystem maxStrategy(const std::map<std::string, T>& assignment) {
+    EquationSystem result;
+    for (typename std::map<std::string, Expression<T> >::const_iterator it = equations.begin();
+         it != equations.end();
+         ++it) {
+      result.add(it->first, it->second.maxStrategyEager(assignment));
+    }
+    return result;
+  }
+
+  private:
+  std::map<std::string, T> eval(const std::map<std::string, T>& assignment, bool infinity, const T& infValue) const {
+    std::map<std::string, T> result;
+    for (typename std::map<std::string, Expression<T> >::const_iterator it = equations.begin();
+         it != equations.end();
+         ++it) {
+      T val = it->second.eval(assignment);
+      if (infinity) {
+        typename std::map<std::string, T>::const_iterator oldEntry = assignment.find(it->first);
+        result[it->first] = (oldEntry->second == val ? val : infValue);
+      } else {
+        result[it->first] = val;
+      }
+    }
+    return result;
+  }
+  std::map<std::string, Expression<T> > equations;
+};
+
+#endif
-- 
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