diff --git a/src/CSVWriter/CSVWriter.hpp b/src/CSVWriter/CSVWriter.hpp
index 974818ac64d0fa9586d5cd449e3b75d7603f50b2..de38b2df7c55c08db99928640b5fa377946624a3 100644
--- a/src/CSVWriter/CSVWriter.hpp
+++ b/src/CSVWriter/CSVWriter.hpp
@@ -16,7 +16,7 @@
 #include <boost/mpl/range_c.hpp>
 #include <boost/mpl/for_each.hpp>
 #include "csv_multiarray.hpp"
-#include "util.hpp"
+#include "util/util.hpp"
 #include "is_csv_writable.hpp"
 
 #define CSV_WRITER 0x30000
diff --git a/src/GraphMLWriter/GraphMLWriter_unit_tests.hpp b/src/GraphMLWriter/GraphMLWriter_unit_tests.hpp
index 36a61f69116c4965f6d823b6efea17747a2463e3..6c9b8c452f7c6da66a91a38c5acc8100744fe4d9 100644
--- a/src/GraphMLWriter/GraphMLWriter_unit_tests.hpp
+++ b/src/GraphMLWriter/GraphMLWriter_unit_tests.hpp
@@ -12,7 +12,7 @@
 
 #include "GraphMLWriter.hpp"
 #include "Graph/CartesianGraphFactory.hpp"
-#include "util.hpp"
+#include "util/util.hpp"
 
 BOOST_AUTO_TEST_SUITE( graphml_writer_test )
 
diff --git a/src/HDF5_wr/HDF5_reader.hpp b/src/HDF5_wr/HDF5_reader.hpp
index 9f8aa1260ef8af578610f45f9488480e62ddc242..d5b4a2ffd0e595220e3048988a5383656f814a0e 100644
--- a/src/HDF5_wr/HDF5_reader.hpp
+++ b/src/HDF5_wr/HDF5_reader.hpp
@@ -20,5 +20,6 @@ class HDF5_reader
 };
 
 #include "HDF5_reader_vd.hpp"
+#include "HDF5_reader_gd.hpp"
 
 #endif /* OPENFPM_IO_SRC_HDF5_WR_HDF5_READER_HPP_ */
diff --git a/src/HDF5_wr/HDF5_wr.hpp b/src/HDF5_wr/HDF5_wr.hpp
index f90c60a4550aa7735c62001e083441ba41e17060..69fa3936cccb8d76065ce8e00812678f6fa21b2a 100644
--- a/src/HDF5_wr/HDF5_wr.hpp
+++ b/src/HDF5_wr/HDF5_wr.hpp
@@ -10,6 +10,7 @@
 
 
 #define VECTOR_DIST 1
+#define GRID_DIST 2
 
 #include "HDF5_writer.hpp"
 #include "HDF5_reader.hpp"
diff --git a/src/HDF5_wr/HDF5_writer.hpp b/src/HDF5_wr/HDF5_writer.hpp
index b0ac16c2779941b497cf8aeee27d3d10f4ee76eb..95b686cf9a4867d49d3110dddfef79ba492670c1 100644
--- a/src/HDF5_wr/HDF5_writer.hpp
+++ b/src/HDF5_wr/HDF5_writer.hpp
@@ -23,6 +23,7 @@ class HDF5_writer
 
 };
 
-#include "../HDF5_wr/HDF5_writer_vd.hpp"
+#include "HDF5_writer_vd.hpp"
+#include "HDF5_writer_gd.hpp"
 
 #endif /* OPENFPM_IO_SRC_HDF5_WR_HDF5_WRITER_HPP_ */
diff --git a/src/Makefile.am b/src/Makefile.am
index b6d6d04e30f89f33f8170fe0f46d3f72e5c63393..d439da5e233bf917c8033beb3213b06a2eea4949 100755
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -8,7 +8,7 @@ io_CFLAGS = $(CUDA_CFLAGS)
 io_LDADD = $(LINKLIBS) 
 
 nobase_include_HEADERS = RawReader/RawReader.hpp RawReader/RawReader_unit_tests.hpp CSVWriter/csv_multiarray.hpp CSVWriter/CSVWriter.hpp CSVWriter/is_csv_writable.hpp \
-GraphMLWriter/GraphMLWriter.hpp util.hpp \
+GraphMLWriter/GraphMLWriter.hpp util/util.hpp \
 VTKWriter/VTKWriter.hpp VTKWriter/byteswap_portable.hpp VTKWriter/VTKWriter_dist_graph.hpp VTKWriter/VTKWriter_graph.hpp VTKWriter/VTKWriter_point_set.hpp  VTKWriter/VTKWriter_grids.hpp VTKWriter/VTKWriter_grids_st.hpp VTKWriter/VTKWriter_grids_util.hpp VTKWriter/VTKWriter_vector_box.hpp VTKWriter/is_vtk_writable.hpp HDF5_wr/HDF5_writer.hpp HDF5_wr/HDF5_writer_vd.hpp HDF5_wr/HDF5_reader.hpp HDF5_wr/HDF5_reader_vd.hpp  \
 Plot/GoogleChart.hpp Plot/util.hpp
 
diff --git a/src/VTKWriter/VTKWriter_vector_box.hpp b/src/VTKWriter/VTKWriter_vector_box.hpp
index 368c451c7cffa19de92ea98efa5a2acc345c761f..2786f21375bd13cffb1ed6147fb5aaa303759f63 100644
--- a/src/VTKWriter/VTKWriter_vector_box.hpp
+++ b/src/VTKWriter/VTKWriter_vector_box.hpp
@@ -11,7 +11,7 @@
 #include <boost/math/special_functions/pow.hpp>
 #include "Space/Shape/HyperCube.hpp"
 #include <random>
-#include "util.hpp"
+#include "util/util.hpp"
 
 template <typename vector>
 class v_box
diff --git a/src/util.hpp b/src/util.hpp
deleted file mode 100644
index f46137ba30972114e1b29f91c73c534f4fd78085..0000000000000000000000000000000000000000
--- a/src/util.hpp
+++ /dev/null
@@ -1,179 +0,0 @@
-/*
- * util.hpp
- *
- *  Created on: May 7, 2015
- *      Author: Pietro Incardona
- */
-
-#include "config.h"
-
-#include "util/SimpleRNG.hpp"
-
-#ifndef UTIL_HPP_
-#define UTIL_HPP_
-
-#include <boost/iostreams/device/mapped_file.hpp>
-
-
-/*! \brief Compare two files, return true if they match
- *
- * \param file1 path1
- * \param file2 path2
- *
- * \return true if they match
- *
- */
-static inline bool compare(std::string file1, std::string file2)
-{
-    boost::iostreams::mapped_file_source f1(file1);
-    boost::iostreams::mapped_file_source f2(file2);
-
-    if( f1.size() == f2.size() && std::equal(f1.data(), f1.data() + f1.size(), f2.data()) )
-        return true;
-    else
-        return false;
-}
-
-//! RGB color struct
-struct RGB
-{
-	//! Red
-	float R;
-
-	//! Green
-	float G;
-
-	//! Blue
-	float B;
-
-	//! Return the color as string
-	std::string toString()
-	{
-		return std::to_string(R) + " " + std::to_string(G) + " " + std::to_string(B);
-	}
-};
-
-/*! \brief Return the color sampled from one group
- *
- * groups:
- *
- * 0: Red
- * 1: Green
- * 2: Blue
- * 3: Yellow
- * 4: Cyan
- * 5: Magenta
- * 6: Orange
- * 7: Chartreuse-Green
- * 8: Spring Green
- * 9: Azure
- * 10: Violet
- * 11: Rose
- *
- * \param group
- *
- */
-
-static inline struct RGB getColor(int group, SimpleRNG & d)
-{
-	struct RGB col;
-
-	float s = (float)d.GetUniform();
-
-	group = group % 12;
-
-#ifdef ON_IO_UNIT_TESTS
-	s = 0.5;
-#endif
-
-	if (group == 0)
-	{
-		col.R = s/2 + 0.5;
-		col.G = 0.0;
-		col.B = 0.0;
-	}
-	else if (group == 1)
-	{
-		col.R = 0.0;
-		col.G = s/2 + 0.5;
-		col.B = 0.0;
-	}
-	else if (group == 2)
-	{
-		col.R = 0.0;
-		col.G = 0.0;
-		col.B = s;
-	}
-	else if (group == 3)
-	{
-		col.R = s/2 + 0.5;
-		col.G = s/2 + 0.5;
-		col.B = 0.0;
-	}
-	else if (group == 4)
-	{
-		col.R = s/2 + 0.5;
-		col.G = 0.0;
-		col.B = s/2 + 0.5;
-	}
-	else if (group == 5)
-	{
-		col.R = 0.0;
-		col.G = s/2 + 0.5;
-		col.B = s/2 + 0.5;
-	}
-	else if (group == 6)
-	{
-		col.R = s/2 + 0.5;
-		col.G = s/4 + 0.5;
-		col.B = 0.0;
-	}
-	else if (group == 7)
-	{
-		col.R = s/4 + 0.5;
-		col.G = s/2 + 0.5;
-		col.B = 0.0;
-	}
-	else if (group == 8)
-	{
-		col.R = 0.0;
-		col.G = s/2 + 0.5;
-		col.B = s/4 + 0.5;
-	}
-	else if (group == 9)
-	{
-		col.R = 0.0;
-		col.G = s/4 + 0.5;
-		col.B = s/2 + 0.5;
-	}
-	else if (group == 10)
-	{
-		col.R = s/4 + 0.5;
-		col.G = 0.0;
-		col.B = s/2 + 0.5;
-	}
-	else
-	{
-		col.R = s/2 + 0.5;
-		col.G = 0.0;
-		col.B = s/4 + 0.5;
-	}
-
-	return col;
-}
-
-/*! \brief Check if one string end with a particular string
- *
- * \param fullString string to check
- * \param ending ending string to check
- *
- */
-static inline bool hasEnding (std::string const &fullString, std::string const &ending)
-{
-    if (fullString.length() >= ending.length())
-    {return (0 == fullString.compare (fullString.length() - ending.length(), ending.length(), ending));}
-    else
-    {return false;}
-}
-
-#endif /* UTIL_HPP_ */