diff --git a/src/multi_array.h b/src/multi_array.h
index ee2dada..d31d1b2 100644
--- a/src/multi_array.h
+++ b/src/multi_array.h
@@ -211,6 +211,8 @@ namespace MultiArrayTools
 	template <class Range2, class Range3>
 	MultiArray(const MultiArray<MultiArray<T,Range2>,Range3> in);
 
+	// implement contstructor using FunctionalMultiArray as Input !!!
+	
 	template <class Range2, class Range3>
 	MultiArray& operator=(const MultiArray<MultiArray<T,Range2>,Range3> in);
 	
@@ -231,6 +233,26 @@ namespace MultiArrayTools
 	std::vector<T> mCont;
     };
 
+    template <typename T, class Range>
+    class FunctionalMultiArray : public MultiArrayBase<T>
+    {
+    public:
+	typedef MultiArrayBase<T,Range> MAB;
+	typedef typename MultiArrayBase<T,Range>::const_iterator const_iterator;
+
+	DEFAULT_MEMBERS(FunctionalMultiArray);
+	FunctionalMultiArray(const Range& range, /*Function*/);
+
+	T& operator[](const typename Range::IndexType& i) override;
+	const T& operator[](const typename Range::IndexType& i) const override;
+
+	virtual bool isConst() const override;	
+	virtual bool isSlice() const override;
+
+    protected:
+	// FUNCTION !!!!
+    };
+    
 }
 
 #include "multi_array.cc"
diff --git a/src/multi_array_operation.cc b/src/multi_array_operation.cc
index 151c354..0b65ea4 100644
--- a/src/multi_array_operation.cc
+++ b/src/multi_array_operation.cc
@@ -513,6 +513,66 @@ namespace MultiArrayTools
 	MAOB::mIibPtr->name(mNm);
     }
 
+    /********************************
+     *   MultiArrayOperationMap     *
+     ********************************/
+
+    template <typename T, class MapFunction, class InRange, class OutRange>
+    MultiArrayOperationMap<T,MapFunction,InRange,OutRange>::
+    MultiArrayOperationMap(MultiArrayOperationRoot<T,OutRange>& root, const MapFunction mf) :
+	MultiArrayOperationBase<T>(),
+	mMF(mf),
+	mRoot(root)
+	//mIndex(mArrayRef.beginIndex()),
+	//mNm(nm)
+    {
+	MAOB::mIibPtr = &mIndex;
+	//MAOB::mIibPtr->name(nm);
+	//mIndex.name(nm);
+    }
+	
+    template <typename T, class MapFunction, class InRange, class OutRange>
+    MultiArrayOperationMap& operator=(const ConstMultiArrayOperationRoot<T,InRange>& in)
+    {
+	mIndex = dynamic_cast<typename InRange::IndexType&>( in.getIndex() );
+	MAOB::mIibPtr = &mIndex;
+	mNm = in.name();
+	mIndex.setPos( mIndex.max() );
+	typename OutRange::IndexType endIndex = mIndex;
+
+	// Implement Map Functions !!!!
+	mRoot.linkIndicesTo( &mMF.index() );
+	mMF.linkIndicesTo( &mIndex );
+
+	MultiArray<size_t,OutRange> cnt(mRoot->range());
+	auto cnto = cnt(mRoot.name(), true);
+	cnto.linkIndicesTo( &mMF.index() )
+	
+	for(mIndex.setPos(0); mIndex != endIndex; ++mIndex){
+	    mRoot.get() += in.get();
+	    ++cnto.get();
+	}
+	mRoot /= cnto;
+    }
+
+    template <typename T, class MapFunction, class InRange, class OutRange>
+    virtual size_t argNum() const override;
+
+    template <typename T, class MapFunction, class InRange, class OutRange>
+    virtual IndefinitIndexBase* getLinked(const std::string& name) const override;
+
+    template <typename T, class MapFunction, class InRange, class OutRange>
+    virtual void linkIndicesTo(IndefinitIndexBase* target) const override;
+
+    template <typename T, class MapFunction, class InRange, class OutRange>
+    virtual void setInternalLinks() const override;
+
+    template <typename T, class MapFunction, class InRange, class OutRange>
+    virtual const T& get() const override;
+
+    template <typename T, class MapFunction, class InRange, class OutRange>
+    virtual T& get() override;
+    
     
     /*****************************
      *   MultiArrayOperation     *
diff --git a/src/multi_array_operation.h b/src/multi_array_operation.h
index 33da214..ad2dd8f 100644
--- a/src/multi_array_operation.h
+++ b/src/multi_array_operation.h
@@ -154,13 +154,6 @@ namespace MultiArrayTools
 
 	void performAssignment(const MultiArrayOperationBase<T>& in);
 
-	/*
-	template <class RangeX>
-	MultiArrayOperationRoot& makeSlice(MultiArrayOperationRoot<T,RangeX>& in);
-	
-	template <class RangeX>
-	const MultiArrayOperationRoot& makeConstSlice(const MultiArrayOperationRoot<T,RangeX>& in);
-	*/
 	MutableMultiArrayBase<T,Range>& mArrayRef;
 	mutable IndexType mIndex;
 	Name mNm;
@@ -238,19 +231,37 @@ namespace MultiArrayTools
 	
     protected:
 
-	/*
-	template <class RangeX>
-	const ConstMultiArrayOperationRoot& makeConstSlice(const ConstMultiArrayOperationRoot<T,RangeX>& in);
-
-	template <class RangeX>
-	const ConstMultiArrayOperationRoot& makeConstSlice(const MultiArrayOperationRoot<T,RangeX>& in);
-	*/
-	// const
 	MultiArrayBase<T,Range> const& mArrayRef;
 	mutable IndexType mIndex;
 	Name mNm;
     };
 
+    template <typename T, class MapFunction, class InRange, class OutRange>
+    class MultiArrayOperationMap : public MutableMultiArrayOperationBase<T>
+    {
+    public:
+	typedef MultiArrayOperationBase<T> MAOB;
+	
+	MultiArrayOperationMap(MultiArrayOperationRoot<T,OutRange>& root, const MapFunction mf);
+	MultiArrayOperationMap& operator=(const ConstMultiArrayOperationRoot<T,InRange>& in);
+
+	virtual size_t argNum() const override;
+
+	virtual IndefinitIndexBase* getLinked(const std::string& name) const override;
+	virtual void linkIndicesTo(IndefinitIndexBase* target) const override;
+
+	virtual void setInternalLinks() const override;
+	
+	virtual const T& get() const override;
+	virtual T& get() override;
+	// !!!!
+    protected:
+	MapFunction mMF;
+	MultiArrayOperationRoot<T,OutRange>& mRoot;
+	mutable IndexType mIndex; // Index of incoming range
+	Name mNm; // Name of incoming range
+    };
+    
     template <typename T, class Operation, class... MAOps>
     class MultiArrayOperation : public MultiArrayOperationBase<T>
     {