From e577a242cb1da3f20bacf6b06bdc674d066d607d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tom=C3=A1=C5=A1=20Pecka?= <peckato1@fit.cvut.cz>
Date: Tue, 4 Mar 2014 22:24:26 +0100
Subject: [PATCH] aTrim now also removes redundant states
---
atrim/src/RedundantStateRemover.cpp | 62 +++++++++++++++++++++++
atrim/src/RedundantStateRemover.h | 32 ++++++++++++
atrim/src/TrimNFA.cpp | 60 +++-------------------
atrim/src/TrimNFA.h | 23 ++-------
atrim/src/UnreachableStateRemover.cpp | 73 +++++++++++++++++++++++++++
atrim/src/UnreachableStateRemover.h | 38 ++++++++++++++
atrim/src/atrim.fsm.cpp | 3 +-
7 files changed, 216 insertions(+), 75 deletions(-)
create mode 100644 atrim/src/RedundantStateRemover.cpp
create mode 100644 atrim/src/RedundantStateRemover.h
create mode 100644 atrim/src/UnreachableStateRemover.cpp
create mode 100644 atrim/src/UnreachableStateRemover.h
diff --git a/atrim/src/RedundantStateRemover.cpp b/atrim/src/RedundantStateRemover.cpp
new file mode 100644
index 0000000000..409aee5cf7
--- /dev/null
+++ b/atrim/src/RedundantStateRemover.cpp
@@ -0,0 +1,62 @@
+/*
+ * RedundantStateRemover.cpp
+ *
+ * Created on: 4. 3. 2014
+ * Author: tomas
+ */
+
+#include "RedundantStateRemover.h"
+
+using namespace automaton;
+using namespace std;
+
+namespace trim
+{
+
+FSM RedundantStateRemover::remove( const FSM & fsm )
+{
+ deque<set<State>> Qi;
+ Qi.push_back( set<State>( ) );
+
+ int i = 1;
+ for( const auto & f : fsm.getFinalStates( ) )
+ Qi.at( 0 ).insert( f );
+
+ while( true )
+ {
+ Qi.push_back( Qi.at( i - 1 ) ); // copy Qi-1 into Qi
+ for( const auto & p : Qi.at( i - 1 ) )
+ for( const auto & t : fsm.getTransitionsToState( p ) )
+ Qi.at( i ).insert( t.getFrom( ) );
+
+ if( Qi.at( i ) == Qi.at( i - 1 ) )
+ break;
+
+ i += 1;
+ }
+
+ FSM ret;
+
+ for( const auto & q : Qi.at( i ) )
+ ret.addState( q );
+
+ for( const auto & t : fsm.getTransitions( ) )
+ {
+ if( isInSet( t.getFrom( ), ret.getStates( ) ) && isInSet( t.getTo( ), ret.getStates( ) ) )
+ {
+ if( ! isInSet( t.getInput( ), ret.getInputAlphabet( ) ) )
+ ret.addInputSymbol( t.getInput( ) );
+
+ ret.addTransition( t );
+ }
+ }
+
+ for( const auto & q : fsm.getInitialStates( ) )
+ ret.addInitialState( q );
+ for( const auto & q : fsm.getFinalStates( ) )
+ ret.addFinalState( q );
+
+ return ret;
+}
+
+} /* namespace trim */
diff --git a/atrim/src/RedundantStateRemover.h b/atrim/src/RedundantStateRemover.h
new file mode 100644
index 0000000000..3ba2e01149
--- /dev/null
+++ b/atrim/src/RedundantStateRemover.h
@@ -0,0 +1,32 @@
+/*
+ * RedundantStateRemover.h
+ *
+ * Created on: 4. 3. 2014
+ * Author: tomas
+ */
+
+#ifndef REDUNDANTSTATEREMOVER_H_
+#define REDUNDANTSTATEREMOVER_H_
+
+#include <deque>
+#include <set>
+
+#include <automaton/FSM/FSM.h>
+
+namespace trim
+{
+
+#define isInSet(x,set) ( (set).find((x)) != (set).end())
+
+/**
+ * Melichar 2.32
+ */
+class RedundantStateRemover
+{
+public:
+ static automaton::FSM remove( const automaton::FSM & fsm );
+};
+
+} /* namespace trim */
+
+#endif /* REDUNDANTSTATEREMOVER_H_ */
diff --git a/atrim/src/TrimNFA.cpp b/atrim/src/TrimNFA.cpp
index bc3c1b46c0..b6a184e831 100644
--- a/atrim/src/TrimNFA.cpp
+++ b/atrim/src/TrimNFA.cpp
@@ -1,71 +1,23 @@
/*
* TrimNFA.cpp
*
- * Created on: 18. 1. 2014
+ * Created on: 4. 3. 2014
* Author: tomas
*/
#include "TrimNFA.h"
-using namespace alib;
using namespace automaton;
-using namespace std;
-using namespace trim;
namespace trim
{
-TrimNFA::TrimNFA( const FSM & fsm ) : m_origFSM( fsm )
+FSM TrimNFA::remove( const FSM & fsm )
{
- if( m_origFSM.getInitialStates( ).size( ) != 1 )
- throw AlibException( "NFA must have exactly one initial state." );
-}
-
-const FSM TrimNFA::remove( void )
-{
- set<State> reachableStates = findReachableStates( );
-
- for( auto const & q : reachableStates )
- m_FSM.addState( q );
-
- for( auto const & symbol : m_origFSM.getInputAlphabet( ) )
- m_FSM.addInputSymbol( symbol );
-
- for( auto const & t : m_origFSM.getTransitions( ) )
- if( isInSet( t.getFrom( ), reachableStates ) )
- m_FSM.addTransition( t );
-
-
- for( auto const & state : m_origFSM.getInitialStates( ) )
- m_FSM.addInitialState( state );
-
-
- set<State> intersect;
- const set<State> & F = m_origFSM.getFinalStates( );
- set_intersection( F.begin(), F.end(), reachableStates.begin(), reachableStates.end(), inserter( intersect, intersect.begin() ) );
-
- for( auto const & state : intersect )
- m_FSM.addFinalState( state );
-
- return m_FSM;
-}
-
-const set<State> TrimNFA::findReachableStates( void ) const
-{
- set<State> qprev, qcurr;
- qcurr.insert( * m_origFSM.getInitialStates().begin() );
-
- do
- {
- qprev = qcurr;
-
- for( auto const & p : qprev )
- for( auto const & transition : m_origFSM.getTransitionsFromState( p ) )
- qcurr.insert( transition.getTo() );
- }
- while( qcurr != qprev );
-
- return qcurr;
+ FSM ret;
+ ret = UnreachableStateRemover::remove( fsm );
+ ret = RedundantStateRemover::remove( ret );
+ return ret;
}
} /* namespace trim */
diff --git a/atrim/src/TrimNFA.h b/atrim/src/TrimNFA.h
index 11523caa52..55f21f9e9e 100644
--- a/atrim/src/TrimNFA.h
+++ b/atrim/src/TrimNFA.h
@@ -1,7 +1,7 @@
/*
* TrimNFA.h
*
- * Created on: 18. 1. 2014
+ * Created on: 4. 3. 2014
* Author: tomas
*/
@@ -9,32 +9,17 @@
#define TRIMNFA_H_
#include <automaton/FSM/FSM.h>
-#include <AlibException.h>
-#include <algorithm>
-#include <iterator>
-#include <map>
-#include <set>
+#include "RedundantStateRemover.h"
+#include "UnreachableStateRemover.h"
namespace trim
{
-#define isInSet(x,set) ( (set).find((x)) != (set).end())
-
-/**
- * Well, this is just simple BFS/DFS, but we implement Melichar, 2.29 algorithm.
- */
class TrimNFA
{
public:
- TrimNFA( const automaton::FSM & fsm );
- const automaton::FSM remove( void );
-
-private:
- const std::set<automaton::State> findReachableStates( void ) const;
-
- const automaton::FSM & m_origFSM;
- automaton::FSM m_FSM;
+ static automaton::FSM remove( const automaton::FSM & fsm );
};
} /* namespace trim */
diff --git a/atrim/src/UnreachableStateRemover.cpp b/atrim/src/UnreachableStateRemover.cpp
new file mode 100644
index 0000000000..3caf41fd80
--- /dev/null
+++ b/atrim/src/UnreachableStateRemover.cpp
@@ -0,0 +1,73 @@
+/*
+ * UnreachableStateRemover.cpp
+ *
+ * Created on: 18. 1. 2014
+ * Author: tomas
+ */
+
+#include "UnreachableStateRemover.h"
+
+using namespace alib;
+using namespace automaton;
+using namespace std;
+using namespace trim;
+
+namespace trim
+{
+
+FSM UnreachableStateRemover::remove( const FSM & fsm )
+{
+ if( fsm.getInitialStates( ).size( ) != 1 )
+ throw AlibException( "NFA must have exactly one initial state." );
+
+ set<State> reachableStates = findReachableStates( fsm );
+
+ FSM ret;
+
+ for( auto const & q : reachableStates )
+ ret.addState( q );
+
+ for( auto const & t : fsm.getTransitions( ) )
+ {
+ if( isInSet( t.getFrom( ), reachableStates ) )
+ {
+ if( ! isInSet( t.getInput( ), ret.getInputAlphabet( ) ) )
+ ret.addInputSymbol( t.getInput( ) );
+ ret.addTransition( t );
+ }
+ }
+
+
+ for( auto const & state : fsm.getInitialStates( ) )
+ ret.addInitialState( state );
+
+
+ set<State> intersect;
+ const set<State> & F = fsm.getFinalStates( );
+ set_intersection( F.begin(), F.end(), reachableStates.begin(), reachableStates.end(), inserter( intersect, intersect.begin() ) );
+
+ for( auto const & state : intersect )
+ ret.addFinalState( state );
+
+ return ret;
+}
+
+set<State> UnreachableStateRemover::findReachableStates( const FSM & fsm )
+{
+ set<State> qprev, qcurr;
+ qcurr.insert( * fsm.getInitialStates().begin() );
+
+ do
+ {
+ qprev = qcurr;
+
+ for( auto const & p : qprev )
+ for( auto const & transition : fsm.getTransitionsFromState( p ) )
+ qcurr.insert( transition.getTo() );
+ }
+ while( qcurr != qprev );
+
+ return qcurr;
+}
+
+} /* namespace trim */
diff --git a/atrim/src/UnreachableStateRemover.h b/atrim/src/UnreachableStateRemover.h
new file mode 100644
index 0000000000..0345ebbc36
--- /dev/null
+++ b/atrim/src/UnreachableStateRemover.h
@@ -0,0 +1,38 @@
+/*
+ * UnreachableStateRemover.h
+ *
+ * Created on: 18. 1. 2014
+ * Author: tomas
+ */
+
+#ifndef UNREACHABLE_H_
+#define UNREACHABLE_H_
+
+#include <automaton/FSM/FSM.h>
+#include <AlibException.h>
+
+#include <algorithm>
+#include <iterator>
+#include <map>
+#include <set>
+
+namespace trim
+{
+
+#define isInSet(x,set) ( (set).find((x)) != (set).end())
+
+/**
+ * Melichar 2.29
+ */
+class UnreachableStateRemover
+{
+public:
+ static automaton::FSM remove( const automaton::FSM & fsm );
+
+private:
+ static std::set<automaton::State> findReachableStates( const automaton::FSM & fsm );
+};
+
+} /* namespace trim */
+
+#endif /* UNREACHABLE_H_ */
diff --git a/atrim/src/atrim.fsm.cpp b/atrim/src/atrim.fsm.cpp
index b52484255d..dd33c147fe 100644
--- a/atrim/src/atrim.fsm.cpp
+++ b/atrim/src/atrim.fsm.cpp
@@ -55,8 +55,7 @@ int main(int argc, char** argv) {
UnknownAutomaton automaton = AutomatonParser::parse( tokens );
FSM fsm = AutomatonFactory::buildFSM( automaton );
- TrimNFA tr ( fsm );
- tr.remove().toXML( cout );
+ TrimNFA::remove( fsm ).toXML( cout );
} catch (AlibException& e) {
cout << e.what() << endl;
--
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