First version of DD iterator; small test included.

Former-commit-id: 2ec2323886

resources/3rdparty/cudd-2.5.0/src/obj/cuddObj.cc

@@ -5280,7 +5280,7 @@ int
 ABDD::NextCube(
   DdGen * gen,
   int ** cube,
-  CUDD_VALUE_TYPE * value) const
+  CUDD_VALUE_TYPE * value) 
 {
     return Cudd_NextCube(gen, cube, value);
 

resources/3rdparty/cudd-2.5.0/src/obj/cuddObj.hh

@@ -192,7 +192,7 @@ public:
 	const;
     int CountLeaves() const;
     DdGen * FirstCube(int ** cube, CUDD_VALUE_TYPE * value) const;
-    int NextCube(DdGen * gen, int ** cube, CUDD_VALUE_TYPE * value) const;
+    static int NextCube(DdGen * gen, int ** cube, CUDD_VALUE_TYPE * value);
     double Density(int nvars) const;
 
 }; // ABDD

src/storage/dd/CuddDd.cpp

@@ -434,6 +434,17 @@ namespace storm {
             return this->ddManager;
         }
         
+        DdForwardIterator<DdType::CUDD> Dd<DdType::CUDD>::begin() const {
+            int* cube;
+            double value;
+            DdGen* generator = this->getCuddAdd().FirstCube(&cube, &value);
+            return DdForwardIterator<DdType::CUDD>(this->getDdManager(), generator, cube, value, Cudd_IsGenEmpty(generator), &this->getContainedMetaVariableNames());
+        }
+        
+        DdForwardIterator<DdType::CUDD> Dd<DdType::CUDD>::end() const {
+            return DdForwardIterator<DdType::CUDD>(this->getDdManager(), nullptr, nullptr, 0, true, nullptr);
+        }
+        
         std::ostream & operator<<(std::ostream& out, const Dd<DdType::CUDD>& dd) {
             dd.exportToDot();
             return out;

src/storage/dd/CuddDd.h

@@ -7,6 +7,7 @@
 #include <iostream>
 
 #include "src/storage/dd/Dd.h"
+#include "src/storage/dd/CuddDdForwardIterator.h"
 #include "src/utility/OsDetection.h"
 
 // Include the C++-interface of CUDD.
@@ -22,6 +23,7 @@ namespace storm {
         public:
             // Declare the DdManager and DdIterator class as friend so it can access the internals of a DD.
             friend class DdManager<DdType::CUDD>;
+            friend class DdForwardIterator<DdType::CUDD>;
             
             // Instantiate all copy/move constructors/assignments with the default implementation.
             Dd() = default;
@@ -405,6 +407,20 @@ namespace storm {
              */
             std::shared_ptr<DdManager<DdType::CUDD>> getDdManager() const;
             
+            /*!
+             * Retrieves an iterator that points to the first meta variable assignment with a non-zero function value.
+             *
+             * @return An iterator that points to the first meta variable assignment with a non-zero function value.
+             */
+            DdForwardIterator<DdType::CUDD> begin() const;
+            
+            /*!
+             * Retrieves an iterator that points past the end of the container.
+             *
+             * @return An iterator that points past the end of the container.
+             */
+            DdForwardIterator<DdType::CUDD> end() const;
+            
             friend std::ostream & operator<<(std::ostream& out, const Dd<DdType::CUDD>& dd);
         private:
             /*!

src/storage/dd/CuddDdForwardIterator.cpp

@@ -1,24 +1,152 @@
 #include "src/storage/dd/CuddDdForwardIterator.h"
+#include "src/storage/dd/CuddDdManager.h"
+#include "src/storage/dd/DdMetaVariable.h"
+#include "src/exceptions/ExceptionMacros.h"
 
 namespace storm {
     namespace dd {
-        DdForwardIterator<DdType::CUDD>::DdForwardIterator(std::shared_ptr<DdManager<DdType::CUDD>> ddManager, ADD cuddAdd) : ddManager(ddManager), value(0), cube(nullptr), cuddAdd(cuddAdd), isAtEnd(false), generator(nullptr) {
-            // Start by getting the first cube.
-            this->generator = this->cuddAdd.FirstCube(&cube, &value);
+        DdForwardIterator<DdType::CUDD>::DdForwardIterator(std::shared_ptr<DdManager<DdType::CUDD>> ddManager, DdGen* generator, int* cube, double value, bool isAtEnd, std::set<std::string> const* metaVariables) : ddManager(ddManager), generator(generator), cube(cube), value(value), isAtEnd(isAtEnd), metaVariables(metaVariables), cubeCounter(), relevantDontCareDdVariables(), currentValuation() {
+            // If the given generator is not yet at its end, we need to create the current valuation from the cube from
+            // scratch.
+            if (!this->isAtEnd) {
+                // Start by registering all meta variables in the valuation with the appropriate type.
+                for (auto const& metaVariableName : *this->metaVariables) {
+                    auto const& metaVariable = this->ddManager->getMetaVariable(metaVariableName);
+                    switch (metaVariable.getType()) {
+                        case DdMetaVariable<DdType::CUDD>::MetaVariableType::Bool: currentValuation.addBooleanIdentifier(metaVariableName); break;
+                        case DdMetaVariable<DdType::CUDD>::MetaVariableType::Int: currentValuation.addIntegerIdentifier(metaVariableName); break;
+                    }
+                }
 
-            // If the generator is already empty, we set the corresponding flag.
-            this->isAtEnd = Cudd_IsGenEmpty(generator);
+                // And then get ready for treating the first cube.
+                this->treatNewCube();
+            }
+        }
+        
+        DdForwardIterator<DdType::CUDD>::DdForwardIterator(DdForwardIterator<DdType::CUDD>&& other) : ddManager(other.ddManager), generator(other.generator), cube(other.cube), value(other.value), isAtEnd(other.isAtEnd), metaVariables(other.metaVariables), cubeCounter(other.cubeCounter), relevantDontCareDdVariables(other.relevantDontCareDdVariables), currentValuation(other.currentValuation) {
+            // Null-out the pointers of which we took possession.
+            other.cube = nullptr;
+            other.generator = nullptr;
+        }
+        
+        DdForwardIterator<DdType::CUDD>& DdForwardIterator<DdType::CUDD>::operator=(DdForwardIterator<DdType::CUDD>&& other) {
+            if (this != &other) {
+                this->ddManager = other.ddManager;
+                this->generator = other.generator;
+                this->cube = other.cube;
+                this->value = other.value;
+                this->isAtEnd = other.isAtEnd;
+                this->metaVariables = other.metaVariables;
+                this->cubeCounter = other.cubeCounter;
+                this->relevantDontCareDdVariables = other.relevantDontCareDdVariables;
+                this->currentValuation = other.currentValuation;
+                
+                // Null-out the pointers of which we took possession.
+                other.cube = nullptr;
+                other.generator = nullptr;
+            }
+            return *this;
+        }
+        
+        DdForwardIterator<DdType::CUDD>::~DdForwardIterator() {
+            if (this->cube != nullptr) {
+                free(this->cube);
+            }
+            if (this->generator != nullptr) {
+                free(this->generator);
+            }
         }
         
         DdForwardIterator<DdType::CUDD>& DdForwardIterator<DdType::CUDD>::operator++() {
-            // TODO: eliminate current
+            LOG_ASSERT(!this->isAtEnd, "Illegally incrementing iterator that is already at its end.");
+            
+            // If there were no (relevant) don't cares or we have enumerated all combination, we need to eliminate the
+            // found solutions and get the next "first" cube.
+            if (this->relevantDontCareDdVariables.empty() || this->cubeCounter >= std::pow(2, this->relevantDontCareDdVariables.size()) - 1) {
+                // Get the next cube and check for emptiness.
+                ABDD::NextCube(generator, &cube, &value);
+                this->isAtEnd = Cudd_IsGenEmpty(generator);
+
+                // In case we are not done yet, we get ready to treat the next cube.
+                if (!this->isAtEnd) {
+                    this->treatNewCube();
+                }
+            } else {
+                // Treat the next solution of the cube.
+                this->treatNextInCube();
+            }
+            
+            return *this;
+        }
+        
+        void DdForwardIterator<DdType::CUDD>::treatNextInCube() {
+            // Start by increasing the counter and check which bits we need to set/unset in the new valuation.
+            ++this->cubeCounter;
+            
+            for (uint_fast64_t index = 0; index < this->relevantDontCareDdVariables.size(); ++index) {
+                auto const& metaVariable = this->ddManager->getMetaVariable(std::get<1>(this->relevantDontCareDdVariables[index]));
+                if (metaVariable.getType() == DdMetaVariable<DdType::CUDD>::MetaVariableType::Bool) {
+                    if ((this->cubeCounter & (1ull << index)) != 0) {
+                        currentValuation.setBooleanValue(metaVariable.getName(), true);
+                    } else {
+                        currentValuation.setBooleanValue(metaVariable.getName(), false);
+                    }
+                } else {
+                    if ((this->cubeCounter & (1ull << index)) != 0) {
+                        currentValuation.setIntegerValue(metaVariable.getName(), ((currentValuation.getIntegerValue(metaVariable.getName()) - metaVariable.getLow()) | (1ull << std::get<2>(this->relevantDontCareDdVariables[index]))) + metaVariable.getLow());
+                    } else {
+                        currentValuation.setIntegerValue(metaVariable.getName(), ((currentValuation.getIntegerValue(metaVariable.getName()) - metaVariable.getLow()) & ~(1ull << std::get<2>(this->relevantDontCareDdVariables[index]))) + metaVariable.getLow());
+                    }
+                }
+            }
+        }
+        
+        void DdForwardIterator<DdType::CUDD>::treatNewCube() {
+            this->relevantDontCareDdVariables.clear();
+            
+            // Now loop through the bits of all meta variables and check whether they need to be set, not set or are
+            // don't cares. In the latter case, we add them to a special list, so we can iterate over their concrete
+            // valuations later.
+            for (auto const& metaVariableName : *this->metaVariables) {
+                auto const& metaVariable = this->ddManager->getMetaVariable(metaVariableName);
+                if (metaVariable.getType() == DdMetaVariable<DdType::CUDD>::MetaVariableType::Bool) {
+                    if (this->cube[metaVariable.getDdVariables()[0].getCuddAdd().NodeReadIndex()] == 0) {
+                        currentValuation.setBooleanValue(metaVariableName, false);
+                    } else if (this->cube[metaVariable.getDdVariables()[0].getCuddAdd().NodeReadIndex()] == 1) {
+                        currentValuation.setBooleanValue(metaVariableName, true);
+                    } else {
+                        relevantDontCareDdVariables.push_back(std::make_tuple(metaVariable.getDdVariables()[0].getCuddAdd(), metaVariableName, 0));
+                    }
+                } else {
+                    int_fast64_t intValue = 0;
+                    for (uint_fast64_t bitIndex = 0; bitIndex < metaVariable.getNumberOfDdVariables(); ++bitIndex) {
+                        if (cube[metaVariable.getDdVariables()[bitIndex].getCuddAdd().NodeReadIndex()] == 0) {
+                            // Leave bit unset.
+                        } else if (cube[metaVariable.getDdVariables()[bitIndex].getCuddAdd().NodeReadIndex()] == 1) {
+                            intValue |= 1ull << (metaVariable.getNumberOfDdVariables() - bitIndex - 1);
+                        } else {
+                            // Temporarily leave bit unset so we can iterate trough the other option later.
+                            // Add the bit to the relevant don't care bits.
+                            this->relevantDontCareDdVariables.push_back(std::make_tuple(metaVariable.getDdVariables()[bitIndex].getCuddAdd(), metaVariableName, metaVariable.getNumberOfDdVariables() - bitIndex - 1));
+                        }
+                    }
+                    currentValuation.setIntegerValue(metaVariableName, intValue + metaVariable.getLow());
+                }
+            }
+            
+            // Finally, reset the cube counter.
+            this->cubeCounter = 0;
         }
         
         bool DdForwardIterator<DdType::CUDD>::operator==(DdForwardIterator<DdType::CUDD> const& other) const {
             if (this->isAtEnd && other.isAtEnd) {
                 return true;
             } else {
-                return this->cuddAdd == other.cuddAdd;
+                return this->ddManager.get() == other.ddManager.get() && this->generator == other.generator
+                && this->cube == other.cube && this->value == other.value && this->isAtEnd == other.isAtEnd
+                && this->metaVariables == other.metaVariables && this->cubeCounter == other.cubeCounter
+                && this->relevantDontCareDdVariables == other.relevantDontCareDdVariables
+                && this->currentValuation == other.currentValuation;
             }
         }
         
@@ -26,8 +154,8 @@ namespace storm {
             return !(*this == other);
         }
         
-        storm::expressions::SimpleValuation DdForwardIterator<DdType::CUDD>::operator*() const {
-            // FIXME: construct valuation and return it.
+        std::pair<storm::expressions::SimpleValuation, double> DdForwardIterator<DdType::CUDD>::operator*() const {
+            return std::make_pair(currentValuation, value);
         }
     }
 }

src/storage/dd/CuddDdForwardIterator.h

@@ -3,6 +3,9 @@
 
 #include <memory>
 #include <cstdint>
+#include <set>
+#include <tuple>
+#include <utility>
 
 #include "src/storage/dd/DdForwardIterator.h"
 #include "src/storage/expressions/SimpleValuation.h"
@@ -12,33 +15,114 @@
 
 namespace storm {
     namespace dd {
+        // Forward-declare the DdManager class.
+        template<DdType Type> class DdManager;
+        template<DdType Type> class Dd;
+        
         template<>
         class DdForwardIterator<DdType::CUDD> {
         public:
-            // Forward-declare the DdManager class.
-            template<DdType Type> class DdManager;
+            friend class Dd<DdType::CUDD>;
+
+            // Default-instantiate the constructor.
+            DdForwardIterator() = default;
+            
+            // Forbid copy-construction and copy assignment, because ownership of the internal pointer is unclear then.
+            DdForwardIterator(DdForwardIterator<DdType::CUDD> const& other) = delete;
+            DdForwardIterator& operator=(DdForwardIterator<DdType::CUDD> const& other) = delete;
+            
+            // Provide move-construction and move-assignment, though.
+            DdForwardIterator(DdForwardIterator<DdType::CUDD>&& other);
+            DdForwardIterator& operator=(DdForwardIterator<DdType::CUDD>&& other);
+            
+            /*!
+             * Destroys the forward iterator and frees the generator as well as the cube if they are not the nullptr.
+             */
+            ~DdForwardIterator();
             
+            /*!
+             * Moves the iterator one position forward.
+             */
             DdForwardIterator<DdType::CUDD>& operator++();
-            storm::expressions::SimpleValuation operator*() const;
+            
+            /*!
+             * Returns a pair consisting of a valuation of meta variables and the value to which this valuation is
+             * mapped. Note that the result is returned by value.
+             *
+             * @return A pair of a valuation and the function value.
+             */
+            std::pair<storm::expressions::SimpleValuation, double> operator*() const;
+            
+            /*!
+             * Compares the iterator with the given one. Two iterators are considered equal when all their underlying
+             * data members are the same or they both are at their end.
+             *
+             * @param other The iterator with which to compare.
+             * @return True if the two iterators are considered equal.
+             */
             bool operator==(DdForwardIterator<DdType::CUDD> const& other) const;
+            
+            /*!
+             * Compares the iterator with the given one. Two iterators are considered unequal iff they are not
+             * considered equal.
+             *
+             * @param other The iterator with which to compare.
+             * @return True if the two iterators are considered unequal.
+             */
             bool operator!=(DdForwardIterator<DdType::CUDD> const& other) const;
             
         private:
-            DdForwardIterator(std::shared_ptr<DdManager<DdType::CUDD>> ddManager, ADD cuddAdd, std::vector<ADD> const& relevantDdVariables);
+            /*!
+             * Constructs a forward iterator using the given generator with the given set of relevant meta variables.
+             *
+             * @param ddManager The manager responsible for the DD over which to iterate.
+             * @param generator The generator used to enumerate the cubes of the DD.
+             * @param cube The cube as represented by CUDD.
+             * @param value The value the cube is mapped to.
+             * @param isAtEnd A flag that indicates whether the iterator is at its end and may not be moved forward any
+             * more.
+             * @param metaVariables The meta variables that appear in the DD.
+             */
+            DdForwardIterator(std::shared_ptr<DdManager<DdType::CUDD>> ddManager, DdGen* generator, int* cube, double value, bool isAtEnd, std::set<std::string> const* metaVariables = nullptr);
+            
+            /*!
+             * Recreates the internal information when a new cube needs to be treated.
+             */
+            void treatNewCube();
             
+            /*!
+             * Updates the internal information when the next solution of the current cube needs to be treated.
+             */
+            void treatNextInCube();
+            
+            // The manager responsible for the meta variables (and therefore the underlying DD).
             std::shared_ptr<DdManager<DdType::CUDD>> ddManager;
             
-            double value;
+            // The CUDD generator used to enumerate the cubes of the DD.
+            DdGen* generator;
             
+            // The currently considered cube of the DD.
             int* cube;
 
-            uint_fast64_t positionInCube;
-
-            ADD cuddAdd;
+            // The function value of the current cube.
+            double value;
             
+            // A flag that indicates whether the iterator is at its end and may not be moved further. This is also used
+            // for the check against the end iterator.
             bool isAtEnd;
             
-            DdGen* generator;
+            // The set of meta variables appearing in the DD.
+            std::set<std::string> const* metaVariables;
+            
+            // A number that represents how many assignments of the current cube have already been returned previously.
+            // This is needed, because cubes may represent many assignments (if they have don't care variables).
+            uint_fast64_t cubeCounter;
+            
+            // A vector of tuples of the form <variable, metaVariableName, bitIndex>.
+            std::vector<std::tuple<ADD, std::string, uint_fast64_t>> relevantDontCareDdVariables;
+            
+            // The current valuation of meta variables.
+            storm::expressions::SimpleValuation currentValuation;
         };
     }
 }

src/storage/dd/CuddDdManager.cpp

@@ -111,6 +111,18 @@ namespace storm {
             metaVariableMap.emplace(name, DdMetaVariable<DdType::CUDD>(name, low, high, variables, this->shared_from_this()));
         }
         
+        void DdManager<DdType::CUDD>::addMetaVariable(std::string const& name) {
+            // Check whether a meta variable already exists.
+            if (this->hasMetaVariable(name)) {
+                throw storm::exceptions::InvalidArgumentException() << "A meta variable '" << name << "' already exists.";
+            }
+            
+            std::vector<Dd<DdType::CUDD>> variables;
+            variables.emplace_back(Dd<DdType::CUDD>(this->shared_from_this(), cuddManager.addVar(), {name}));
+            
+            metaVariableMap.emplace(name, DdMetaVariable<DdType::CUDD>(name, variables, this->shared_from_this()));
+        }
+        
         void DdManager<DdType::CUDD>::addMetaVariablesInterleaved(std::vector<std::string> const& names, int_fast64_t low, int_fast64_t high) {
             // Make sure that at least one meta variable is added.
             if (names.size() == 0) {

src/storage/dd/CuddDdManager.h

@@ -5,7 +5,6 @@
 
 #include "src/storage/dd/DdManager.h"
 #include "src/storage/dd/DdMetaVariable.h"
-#include "src/storage/dd/CuddDd.h"
 #include "src/utility/OsDetection.h"
 
 // Include the C++-interface of CUDD.
@@ -16,7 +15,6 @@ namespace storm {
         template<>
         class DdManager<DdType::CUDD> : public std::enable_shared_from_this<DdManager<DdType::CUDD>> {
         public:
-            // To break the cylic dependencies, we need to forward-declare the other DD-related classes.
             friend class Dd<DdType::CUDD>;
             
             /*!
@@ -83,7 +81,7 @@ namespace storm {
             Dd<DdType::CUDD> getIdentity(std::string const& metaVariableName);
             
             /*!
-             * Adds a meta variable with the given name and range.
+             * Adds an integer meta variable with the given name and range.
              *
              * @param name The name of the meta variable.
              * @param low The lowest value of the range of the variable.
@@ -92,7 +90,15 @@ namespace storm {
             void addMetaVariable(std::string const& name, int_fast64_t low, int_fast64_t high);
             
             /*!
-             * Adds meta variables with the given names and (equal) range and arranges the DD variables in an interleaved order.
+             * Adds a boolean meta variable with the given name.
+             *
+             * @param name The name of the meta variable.
+             */
+            void addMetaVariable(std::string const& name);
+            
+            /*!
+             * Adds integer meta variables with the given names and (equal) range and arranges the DD variables in an
+             * interleaved order.
              *
              * @param names The names of the variables.
              * @param low The lowest value of the ranges of the variables.

src/storage/dd/DdMetaVariable.cpp

@@ -4,7 +4,15 @@
 namespace storm {
     namespace dd {
         template<DdType Type>
-        DdMetaVariable<Type>::DdMetaVariable(std::string const& name, int_fast64_t low, int_fast64_t high, std::vector<Dd<Type>> const& ddVariables, std::shared_ptr<DdManager<Type>> manager) : name(name), low(low), high(high), ddVariables(ddVariables), cube(manager->getOne()), manager(manager) {
+        DdMetaVariable<Type>::DdMetaVariable(std::string const& name, int_fast64_t low, int_fast64_t high, std::vector<Dd<Type>> const& ddVariables, std::shared_ptr<DdManager<Type>> manager) : name(name), type(MetaVariableType::Int), low(low), high(high), ddVariables(ddVariables), cube(manager->getOne()), manager(manager) {
+            // Create the cube of all variables of this meta variable.
+            for (auto const& ddVariable : this->ddVariables) {
+                this->cube *= ddVariable;
+            }
+        }
+        
+        template<DdType Type>
+        DdMetaVariable<Type>::DdMetaVariable(std::string const& name, std::vector<Dd<Type>> const& ddVariables, std::shared_ptr<DdManager<Type>> manager) : name(name), type(MetaVariableType::Bool), ddVariables(ddVariables), cube(manager->getOne()), manager(manager) {
             // Create the cube of all variables of this meta variable.
             for (auto const& ddVariable : this->ddVariables) {
                 this->cube *= ddVariable;
@@ -16,6 +24,11 @@ namespace storm {
             return this->name;
         }
         
+        template<DdType Type>
+        typename DdMetaVariable<Type>::MetaVariableType DdMetaVariable<Type>::getType() const {
+            return this->type;
+        }
+        
         template<DdType Type>
         int_fast64_t DdMetaVariable<Type>::getLow() const {
             return this->low;

src/storage/dd/DdMetaVariable.h

@@ -8,6 +8,7 @@
 
 #include "utility/OsDetection.h"
 #include "src/storage/dd/CuddDd.h"
+#include "src/storage/expressions/Expression.h"
 
 namespace storm {
     namespace dd {
@@ -20,9 +21,13 @@ namespace storm {
             // Declare the DdManager class as friend so it can access the internals of a meta variable.
             friend class DdManager<Type>;
             friend class Dd<Type>;
+            friend class DdForwardIterator<Type>;
+            
+            // An enumeration for all legal types of meta variables.
+            enum class MetaVariableType { Bool, Int };
             
             /*!
-             * Creates a meta variable with the given name, range bounds.
+             * Creates an integer meta variable with the given name and range bounds.
              *
              * @param name The name of the meta variable.
              * @param low The lowest value of the range of the variable.
@@ -32,6 +37,14 @@ namespace storm {
              */
             DdMetaVariable(std::string const& name, int_fast64_t low, int_fast64_t high, std::vector<Dd<Type>> const& ddVariables, std::shared_ptr<DdManager<Type>> manager);
             
+            /*!
+             * Creates a boolean meta variable with the given name.
+             * @param name The name of the meta variable.
+             * @param ddVariables The vector of variables used to encode this variable.
+             * @param manager A pointer to the manager that is responsible for this meta variable.
+             */
+            DdMetaVariable(std::string const& name, std::vector<Dd<Type>> const& ddVariables, std::shared_ptr<DdManager<Type>> manager);
+            
             // Explictly generate all default versions of copy/move constructors/assignments.
             DdMetaVariable(DdMetaVariable const& other) = default;
 			DdMetaVariable& operator=(DdMetaVariable const& other) = default;
@@ -47,6 +60,13 @@ namespace storm {
              */
             std::string const& getName() const;
             
+            /*!
+             * Retrieves the type of the meta variable.
+             *
+             * @return The type of the meta variable.
+             */
+            MetaVariableType getType() const;
+            
             /*!
              * Retrieves the lowest value of the range of the variable.
              *
@@ -93,6 +113,9 @@ namespace storm {
             // The name of the meta variable.
             std::string name;
             
+            // The type of the variable.
+            MetaVariableType type;
+            
             // The lowest value of the range of the variable.
             int_fast64_t low;
             

src/storage/expressions/SimpleValuation.cpp

@@ -1,6 +1,7 @@
-#include "src/storage/expressions/SimpleValuation.h"
-
 #include <boost/functional/hash.hpp>
+#include "src/storage/expressions/SimpleValuation.h"
+#include "src/exceptions/ExceptionMacros.h"
+#include "src/exceptions/InvalidArgumentException.h"
 
 namespace storm {
     namespace expressions {
@@ -13,16 +14,22 @@ namespace storm {
         }
         
         void SimpleValuation::addBooleanIdentifier(std::string const& name, bool initialValue) {
+            LOG_THROW(this->booleanIdentifierToIndexMap->find(name) == this->booleanIdentifierToIndexMap->end(), storm::exceptions::InvalidArgumentException, "Boolean identifier '" << name << "' already registered.");
+            
             this->booleanIdentifierToIndexMap->emplace(name, this->booleanValues.size());
             this->booleanValues.push_back(false);
         }
         
         void SimpleValuation::addIntegerIdentifier(std::string const& name, int_fast64_t initialValue) {
+            LOG_THROW(this->booleanIdentifierToIndexMap->find(name) == this->booleanIdentifierToIndexMap->end(), storm::exceptions::InvalidArgumentException, "Integer identifier '" << name << "' already registered.");
+
             this->integerIdentifierToIndexMap->emplace(name, this->integerValues.size());
             this->integerValues.push_back(initialValue);
         }
         
         void SimpleValuation::addDoubleIdentifier(std::string const& name, double initialValue) {
+            LOG_THROW(this->booleanIdentifierToIndexMap->find(name) == this->booleanIdentifierToIndexMap->end(), storm::exceptions::InvalidArgumentException, "Double identifier '" << name << "' already registered.");
+
             this->doubleIdentifierToIndexMap->emplace(name, this->doubleValues.size());
             this->doubleValues.push_back(initialValue);
         }

test/functional/storage/CuddDdTest.cpp

@@ -273,3 +273,24 @@ TEST(CuddDd, GetSetValueTest) {
     metaVariableToValueMap.emplace("x", 4);
     EXPECT_EQ(2, dd1.getValue(metaVariableToValueMap));
 }
+
+TEST(CuddDd, ForwardIteratorTest) {
+    std::shared_ptr<storm::dd::DdManager<storm::dd::DdType::CUDD>> manager(new storm::dd::DdManager<storm::dd::DdType::CUDD>());
+    manager->addMetaVariable("x", 1, 9);
+    manager->addMetaVariable("y", 0, 3);
+    
+    storm::dd::Dd<storm::dd::DdType::CUDD> dd;
+    ASSERT_NO_THROW(dd = manager->getRange("x"));
+    
+    storm::dd::DdForwardIterator<storm::dd::DdType::CUDD> it, ite;
+    ASSERT_NO_THROW(it = dd.begin());
+    ASSERT_NO_THROW(ite = dd.end());
+    std::pair<storm::expressions::SimpleValuation, double> valuationValuePair;
+    uint_fast64_t numberOfValuations = 0;
+    while (it != ite) {
+        ASSERT_NO_THROW(valuationValuePair = *it);
+        ASSERT_NO_THROW(++it);
+        ++numberOfValuations;
+    }
+    EXPECT_EQ(9, numberOfValuations);
+}