X-Git-Url: http://bilbo.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/fa640887e373f7bf7dcba89d3e07a44dd9028b7b..f5486d14082380bb49065dead209967410995a2a:/src/mc/explo/udpor/EventSet.cpp

diff --git a/src/mc/explo/udpor/EventSet.cpp b/src/mc/explo/udpor/EventSet.cpp
index 3982cbeeae..33442cd16d 100644
--- a/src/mc/explo/udpor/EventSet.cpp
+++ b/src/mc/explo/udpor/EventSet.cpp
@@ -6,8 +6,10 @@
 #include "src/mc/explo/udpor/EventSet.hpp"
 #include "src/mc/explo/udpor/Configuration.hpp"
 #include "src/mc/explo/udpor/History.hpp"
+#include "src/mc/explo/udpor/UnfoldingEvent.hpp"
 
 #include <iterator>
+#include <stack>
 
 namespace simgrid::mc::udpor {
 
@@ -135,4 +137,80 @@ bool EventSet::is_maximal() const
   return *this == history.get_all_maximal_events();
 }
 
+bool EventSet::is_conflict_free() const
+{
+  return false;
+}
+
+std::vector<const UnfoldingEvent*> EventSet::get_topological_ordering() const
+{
+  // This is essentially an implementation of detecting cycles
+  // in a graph with coloring, except it makes a topological
+  // ordering out of it
+  if (empty()) {
+    return std::vector<const UnfoldingEvent*>();
+  }
+
+  std::stack<const UnfoldingEvent*> event_stack;
+  std::vector<const UnfoldingEvent*> topological_ordering;
+  EventSet unknown_events = *this;
+  EventSet temporarily_marked_events;
+  EventSet permanently_marked_events;
+
+  while (not unknown_events.empty()) {
+    EventSet discovered_events;
+    event_stack.push(*unknown_events.begin());
+
+    while (not event_stack.empty()) {
+      const UnfoldingEvent* evt = event_stack.top();
+      discovered_events.insert(evt);
+
+      if (not temporarily_marked_events.contains(evt)) {
+        // If this event hasn't yet been marked, do
+        // so now so that if we both see it
+        // again in a child we can detect a cycle
+        temporarily_marked_events.insert(evt);
+
+        EventSet immediate_causes = evt->get_immediate_causes();
+        if (!immediate_causes.empty() && immediate_causes.is_subset_of(temporarily_marked_events)) {
+          throw std::invalid_argument("Attempted to perform a topological sort on a configuration "
+                                      "whose contents contain a cycle. The configuration (and the graph "
+                                      "connecting all of the events) is an invalid event structure");
+        }
+        immediate_causes.subtract(discovered_events);
+        immediate_causes.subtract(permanently_marked_events);
+        std::for_each(immediate_causes.begin(), immediate_causes.end(),
+                      [&event_stack](const UnfoldingEvent* cause) { event_stack.push(cause); });
+      } else {
+        unknown_events.remove(evt);
+        temporarily_marked_events.remove(evt);
+        permanently_marked_events.insert(evt);
+
+        // In moving this event to the end of the list,
+        // we are saying this events "happens before" other
+        // events that are added later.
+        if (this->contains(evt)) {
+          topological_ordering.push_back(evt);
+        }
+
+        // Only now do we remove the event, i.e. once
+        // we've processed the same event twice
+        event_stack.pop();
+      }
+    }
+  }
+  return topological_ordering;
+}
+
+std::vector<const UnfoldingEvent*> EventSet::get_topological_ordering_of_reverse_graph() const
+{
+  // The implementation exploits the property that
+  // a topological sorting S^R of the reverse graph G^R
+  // of some graph G is simply the reverse of any
+  // topological sorting S of G.
+  auto topological_events = get_topological_ordering();
+  std::reverse(topological_events.begin(), topological_events.end());
+  return topological_events;
+}
+
 } // namespace simgrid::mc::udpor
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