diff --git a/src/examples/FilesAndFilters/FilesAndFilters.cpp b/src/examples/FilesAndFilters/FilesAndFilters.cpp
index ea9c73b..cd86360 100644
--- a/src/examples/FilesAndFilters/FilesAndFilters.cpp
+++ b/src/examples/FilesAndFilters/FilesAndFilters.cpp
@@ -32,16 +32,16 @@ int main()
 {
 	//Declare class and input variables
 	Persistence1D p;
-	vector<float> data;
-	float currdata; 
+	vector<double> data;
+	double currdata; 
 	ifstream datafile;
 	char * filename = "data.txt";
 	
 	//Declare variables for results
 	vector<TPairedExtrema> pairs;	
-	vector<int> min, max;			
-	int globalMinIndex;
-	float globalMinValue;
+	vector<size_t> min, max;			
+	size_t globalMinIndex;
+	double globalMinValue;
 	
 
 	//Open the data file for reading
@@ -77,7 +77,7 @@ int main()
 		
 	//Now set a threshold for features filtering
 	//In this case, we choose a threshold between largest and smallest persistence, to select from of the data.
-	float filterThreshold = (pairs.front().Persistence + pairs.back().Persistence)/2;
+	double filterThreshold = (pairs.front().Persistence + pairs.back().Persistence)/2;
 	
 	//The vector which hold the data for the Get functions are being reset before use.
 	//Use them to retrieve the filtered results:
diff --git a/src/examples/MatlabVisualization/MatlabVisualization.cpp b/src/examples/MatlabVisualization/MatlabVisualization.cpp
index 99a3d9f..b8ca8b5 100644
--- a/src/examples/MatlabVisualization/MatlabVisualization.cpp
+++ b/src/examples/MatlabVisualization/MatlabVisualization.cpp
@@ -40,8 +40,8 @@ int main()
 {
 	//Input and class variables declaration
 	Persistence1D p;
-	vector<float> data;
-	float currdata; 
+	vector<double> data;
+	double currdata; 
 	ifstream datafile;
 	ofstream outfile;
 	char * filename = "data.txt";
@@ -49,8 +49,8 @@ int main()
 	bool enableMatlabIndexing = true;
 
 	//Output variables declaration
-	vector<int> min, max;			
-	int globalMinIndex;
+	vector<size_t> min, max;			
+	size_t globalMinIndex;
 	
 	//Open and read the data file
 	datafile.open(filename);
@@ -78,7 +78,7 @@ int main()
 	}
 	
 	//Now, set a threshold for features filtering
-	float filterThreshold = 1.0;
+	double filterThreshold = 1.0;
 	
 	//Retrieve the filtered results from the class. 
 	//Since results are intended to be used within Matlab, set MatlabIndexing in all Get function calls
@@ -92,7 +92,7 @@ int main()
 	if (!outfile)
 		return -2;
 	
-	for (unsigned int i = 0; i < min.size() && i < max.size(); i++)
+	for (size_t i = 0; i < min.size() && i < max.size(); i++)
 	{
 		outfile << min[i] << endl;
 		outfile << max[i] << endl;
diff --git a/src/examples/SimpleDataVector/SimpleDataVector.cpp b/src/examples/SimpleDataVector/SimpleDataVector.cpp
index 9cc9d31..841d35b 100644
--- a/src/examples/SimpleDataVector/SimpleDataVector.cpp
+++ b/src/examples/SimpleDataVector/SimpleDataVector.cpp
@@ -28,7 +28,7 @@ using namespace p1d;
 int main()
 {
 	//Create some data
-	vector< float > data;
+	vector<double> data;
 	data.push_back(2.0);   data.push_back(5.0);   data.push_back(7.0);
 	data.push_back(-12.0); data.push_back(-13.0); data.push_back(-7.0);
 	data.push_back(10.0);  data.push_back(18.0);  data.push_back(6.0);
diff --git a/src/persistence1d/persistence1d.hpp b/src/persistence1d/persistence1d.hpp
index 52114df..889cb08 100644
--- a/src/persistence1d/persistence1d.hpp
+++ b/src/persistence1d/persistence1d.hpp
@@ -35,10 +35,10 @@ struct TIdxAndData
 	}
 
 	///The index of the vertex within the Data vector. 
-	int Idx;
+	size_t Idx;
 
 	///Vertex data value from the original Data vector sent as an argument to RunPersistence.
-	float Data;
+	double Data;
 };
 
 
@@ -51,14 +51,14 @@ struct TComponent
 	///A component is defined by the indices of its edges.
 	///Both variables hold the respective indices of the vertices in Data vector.
 	///All vertices between them are considered to belong to this component.
-	int LeftEdgeIndex;
-	int RightEdgeIndex;
+	size_t LeftEdgeIndex;
+	size_t RightEdgeIndex;
 
 	///The index of the local minimum within the component as longs as its alive. 
-	int MinIndex;
+	size_t MinIndex;
 
 	///The value of the Data[MinIndex].
-	float MinValue; //redundant, but makes life easier
+	double MinValue; //redundant, but makes life easier
 
 	///Set to true when a component is created. Once components are merged,
 	///the destroyed component Alive value is set to false. 
@@ -74,15 +74,15 @@ struct TComponent
 struct TPairedExtrema
 {
 	///Index of local minimum, as per Data vector.
-	int MinIndex;
+	size_t MinIndex;
 
 	///Index of local maximum, as per Data vector. 
-	int MaxIndex;
+	size_t MaxIndex;
 
 	///The persistence of the two extrema.
 	///Data[MaxIndex] - Data[MinIndex]		 
 	///Guaranteed to be >= 0.
-	float Persistence;	
+	double Persistence;	
 
 	bool operator<(const TPairedExtrema& other) const
 	{
@@ -125,7 +125,7 @@ class Persistence1D
 
 		@param[in] InputData Vector of data to find features on, ordered according to its axis.
 	*/
-	bool RunPersistence(const std::vector<float>& InputData)
+	bool RunPersistence(const std::vector<double>& InputData)
 	{	
 		Data = InputData; 
 		Init();
@@ -153,7 +153,7 @@ class Persistence1D
 	void PrintPairs(const std::vector<TPairedExtrema>& pairs) const 
 	{
 		for (std::vector<TPairedExtrema>::const_iterator it = pairs.begin(); 
-			it != pairs.end(); it++)
+			it != pairs.end(); ++it)
 		{
 			std::cout	<< "Persistence: " << (*it).Persistence
 						<< " minimum index: " << (*it).MinIndex
@@ -169,7 +169,7 @@ class Persistence1D
 		@param[in] threshold		Threshold value for pair persistence.
 		@param[in] matlabIndexing	Use Matlab indexing for printing.
 	*/	
-	void PrintResults(const float threshold = 0.0, const bool matlabIndexing = false) const
+	void PrintResults(const double threshold = 0.0, const bool matlabIndexing = false) const
 	{
 		if (threshold < 0)
 		{
@@ -203,7 +203,7 @@ class Persistence1D
 		
 		@param[in] matlabIndexing	Set this to true to change all indices of features to Matlab's 1-indexing.
 	*/
-	bool GetPairedExtrema(std::vector<TPairedExtrema> & pairs, const float threshold = 0, const bool matlabIndexing = false) const
+	bool GetPairedExtrema(std::vector<TPairedExtrema> & pairs, const double threshold = 0, const bool matlabIndexing = false) const
 	{
 		//make sure the user does not use previous results that do not match the data
 		pairs.clear();
@@ -218,7 +218,7 @@ class Persistence1D
 		
 		if (matlabIndexing) //match matlab indices by adding one
 		{
-			for (std::vector<TPairedExtrema>::iterator p = pairs.begin(); p != pairs.end(); p++)
+			for (std::vector<TPairedExtrema>::iterator p = pairs.begin(); p != pairs.end(); ++p)
 			{
 				(*p).MinIndex += MATLAB_INDEX_FACTOR;
 				(*p).MaxIndex += MATLAB_INDEX_FACTOR;			
@@ -238,7 +238,7 @@ class Persistence1D
 	@param[in]	threshold		Return only indices for pairs whose persistence is greater than or equal to threshold. 
 	@param[in]	matlabIndexing	Set this to true to change all indices to match Matlab's 1-indexing.
 */
-	bool GetExtremaIndices(std::vector<int> & min, std::vector<int> & max, const float threshold = 0, const bool matlabIndexing = false) const
+	bool GetExtremaIndices(std::vector<size_t> & min, std::vector<size_t> & max, const double threshold = 0, const bool matlabIndexing = false) const
 	{
 		//before doing anything, make sure the user does not use old results
 		min.clear();
@@ -249,12 +249,12 @@ class Persistence1D
 		min.reserve(PairedExtrema.size());
 		max.reserve(PairedExtrema.size());
 		
-		int matlabIndexFactor = 0;
+		size_t matlabIndexFactor = 0;
 		if (matlabIndexing) matlabIndexFactor = MATLAB_INDEX_FACTOR;
 
 		std::vector<TPairedExtrema>::const_iterator lower_bound = FilterByPersistence(threshold);
 
-		for (std::vector<TPairedExtrema>::const_iterator p = lower_bound; p != PairedExtrema.end(); p++)
+		for (std::vector<TPairedExtrema>::const_iterator p = lower_bound; p != PairedExtrema.end(); ++p)
 		{
 			min.push_back((*p).MinIndex + matlabIndexFactor);
 			max.push_back((*p).MaxIndex + matlabIndexFactor);
@@ -266,9 +266,9 @@ class Persistence1D
 		The global minimum does not get paired and is not returned 
 		via GetPairedExtrema and GetExtremaIndices.
 	*/
-	int GetGlobalMinimumIndex(const bool matlabIndexing = false) const
+	size_t GetGlobalMinimumIndex(const bool matlabIndexing = false) const
 	{
-		if (Components.empty()) return -1;
+		if (Components.empty()) return 0;
 
 		assert(Components.front().Alive);
 		if (matlabIndexing)
@@ -284,9 +284,9 @@ class Persistence1D
 		The global minimum does not get paired and is not returned 
 		via GetPairedExtrema and GetExtremaIndices.
 	*/
-	float GetGlobalMinimumValue() const
+	double GetGlobalMinimumValue() const
 	{
-		if (Components.empty()) return 0;
+		if (Components.empty()) return 0.0;
 
 		assert(Components.front().Alive);
 		return Components.front().MinValue;
@@ -304,12 +304,12 @@ class Persistence1D
 	bool VerifyResults() 
 	{
 		bool flag = true; 
-		std::vector<int> min, max;
-		std::vector<int> combinedIndices;
+		std::vector<size_t> min, max;
+		std::vector<size_t> combinedIndices;
 		
 		GetExtremaIndices(min, max);
 
-		int globalMinIdx = GetGlobalMinimumIndex();
+		size_t globalMinIdx = GetGlobalMinimumIndex();
 				
 		std::sort(min.begin(), min.end());
 		std::sort(max.begin(), max.end());
@@ -323,11 +323,11 @@ class Persistence1D
 		   flag = false;
 		}
 
-		if ((globalMinIdx > (int)Data.size()-1) || (globalMinIdx < -1)) flag = false;
-		if (globalMinIdx == -1 && min.size() != 0) flag = false;
+		if ((globalMinIdx > Data.size()-1) || Components.empty()) flag = false;
+		if (Components.empty() && min.size() != 0) flag = false;
 		
-		std::vector<int>::iterator minUniqueEnd = std::unique(min.begin(), min.end());
-		std::vector<int>::iterator maxUniqueEnd = std::unique(max.begin(), max.end());
+		std::vector<size_t>::iterator minUniqueEnd = std::unique(min.begin(), min.end());
+		std::vector<size_t>::iterator maxUniqueEnd = std::unique(max.begin(), max.end());
 				
 		if (minUniqueEnd != min.end() ||
 			maxUniqueEnd != max.end() ||
@@ -343,7 +343,7 @@ class Persistence1D
 	/*!
 		Contain a copy of the original input data.
 	*/
-	std::vector<float> Data;
+	std::vector<double> Data;
 	
 	
 	/*!
@@ -373,7 +373,7 @@ class Persistence1D
 	std::vector<TPairedExtrema> PairedExtrema;
 	
 		
-	unsigned int TotalComponents;	//keeps track of component vector size and newest component "color"
+	size_t TotalComponents;	//keeps track of component vector size and newest component "color"
 	bool AliveComponentsVerified;	//Index of global minimum in Data vector. This minimum is never paired.
 	
 	
@@ -386,9 +386,9 @@ class Persistence1D
 
 		@param[in] firstIdx,secondIdx	Indices of components to be merged. Their order does not matter. 
 	*/
-	void MergeComponents(const int firstIdx, const int secondIdx)
+	void MergeComponents(const size_t firstIdx, const size_t secondIdx)
 	{
-		int survivorIdx, destroyedIdx;
+		size_t survivorIdx, destroyedIdx;
 		//survivor - component whose hub is bigger
 		if (Components[firstIdx].MinValue < Components[secondIdx].MinValue)
 		{
@@ -435,7 +435,7 @@ class Persistence1D
 
 		@param[in] firstIdx, secondIdx Indices of vertices to be paired. Order does not matter. 
 	*/
-	void CreatePairedExtrema(const int firstIdx, const int secondIdx)
+	void CreatePairedExtrema(const size_t firstIdx, const size_t secondIdx)
 	{
 		TPairedExtrema pair; 
 		
@@ -488,7 +488,7 @@ class Persistence1D
 
 	@param[in]	minIdx Index of a local minimum. 
 	*/
-	void CreateComponent(const int minIdx)
+	void CreateComponent(const size_t minIdx)
 	{
 		TComponent comp;
 		comp.Alive = true;
@@ -518,7 +518,7 @@ class Persistence1D
 		@param[in]	componentIdx	Index of component (the value of a neighboring vertex in Colors[]).
 		@param[in] 	dataIdx			Index of vertex which the component is extended to.
 	*/
-	void ExtendComponent(const int componentIdx, const int dataIdx)
+	void ExtendComponent(const size_t componentIdx, const size_t dataIdx)
 	{
 #ifdef _DEUBG
 		assert(Components[componentIdx].Alive == true)
@@ -538,7 +538,7 @@ class Persistence1D
 		{
 #ifdef _DEUBG
 			std::string errorMessage = "ExtendComponent: index mismatch. Data index: ";
-			errorMessage += std::to_string((long long)dataIdx);
+			errorMessage += std::to_string(dataIdx);
 			throw (errorMessage);
 #endif 
 		}
@@ -563,7 +563,7 @@ class Persistence1D
 		Colors.resize(Data.size());
 		std::fill(Colors.begin(), Colors.end(), NO_COLOR);
 		
-		int vectorSize = (int)(Data.size()/RESIZE_FACTOR) + 1; //starting reserved size >= 1 at least
+		size_t vectorSize = (size_t)(Data.size()/RESIZE_FACTOR) + 1; //starting reserved size >= 1 at least
 		
 		Components.clear();
 		Components.reserve(vectorSize);
@@ -584,13 +584,13 @@ class Persistence1D
 	{
 		if (Data.size()==0) return;
 				
-		for (std::vector<float>::size_type i = 0; i != Data.size(); i++)
+		for (std::vector<double>::size_type i = 0; i != Data.size(); ++i)
 		{
 			TIdxAndData dataidxpair; 
 
 			//this is going to make problems
 			dataidxpair.Data = Data[i]; 
-			dataidxpair.Idx = (int)i; 
+			dataidxpair.Idx = i; 
 
 			SortedData.push_back(dataidxpair);
 		}
@@ -617,9 +617,9 @@ class Persistence1D
 			return;
 		}
 
-		for (std::vector<TIdxAndData>::iterator p = SortedData.begin(); p != SortedData.end(); p++)
+		for (std::vector<TIdxAndData>::iterator p = SortedData.begin(); p != SortedData.end(); ++p)
 		{
-			int i = (*p).Idx;
+			size_t i = (*p).Idx;
 
 			//left most vertex - no left neighbor
 			//two options - either local minimum, or extend component
@@ -664,7 +664,7 @@ class Persistence1D
 			}
 			else if (Colors[i-1] != NO_COLOR && Colors[i+1] != NO_COLOR) //local maximum - merge components
 			{
-				int leftComp, rightComp; 
+				size_t leftComp, rightComp; 
 
 				leftComp = Colors[i-1];
 				rightComp = Colors[i+1]; 
@@ -702,7 +702,7 @@ class Persistence1D
 		
 		@param[in]	threshold	Minimum persistence of features to be returned.		
 	*/
-	std::vector<TPairedExtrema>::const_iterator FilterByPersistence(const float threshold = 0) const
+	std::vector<TPairedExtrema>::const_iterator FilterByPersistence(const double threshold = 0) const
 	{		
 		if (threshold == 0 || threshold < 0) return PairedExtrema.begin();
 
@@ -733,7 +733,7 @@ class Persistence1D
 #endif
 		}
 		
-		for (std::vector<TComponent>::const_iterator it = Components.begin()+1; it != Components.end(); it++)
+		for (std::vector<TComponent>::const_iterator it = Components.begin()+1; it != Components.end(); ++it)
 		{
 			if ((*it).Alive == true) 
 			{
@@ -751,4 +751,4 @@ class Persistence1D
 	}
 };
 }
-#endif
\ No newline at end of file
+#endif
diff --git a/src/persistence1d/persistence1d_driver.cpp b/src/persistence1d/persistence1d_driver.cpp
index b7c1926..b32c838 100644
--- a/src/persistence1d/persistence1d_driver.cpp
+++ b/src/persistence1d/persistence1d_driver.cpp
@@ -6,7 +6,7 @@
  *
  *  Command line: persistence1d_driver.exe	\<filename\> [threshold] [-MATLAB]
  *			- filename is the path to a data text file.
- *			  Data is assumed to be formatted as a single float-compatible value per row. 
+ *			  Data is assumed to be formatted as a single double-compatible value per row. 
  *			- [Optional] threshold is a floating point value. Acceptable threshold value >= 0
  *			- [Optional] -MATLAB - output indices match Matlab 1-indexing convention.
  *  Output:	- Indices of extrema, written to a text file, one value per row.
@@ -24,6 +24,7 @@
 
 #include <fstream>
 #include <string>
+#include <cstring>
 
 #define MATLAB "-MATLAB"
 
@@ -32,18 +33,18 @@ using namespace p1d;
 
 
 /*!
-	Tries to open the input file and read its contents to a float vector.
+	Tries to open the input file and read its contents to a double vector.
 	
-	Input is assumed to be formatted as one number per line, in float compatible notation.
+	Input is assumed to be formatted as one number per line, in double compatible notation.
 	
 	Ignores any lines which do not conform to this assumption.
 
 	Number of data entries is assumed to be smaller than vector's class maximum size - this is not checked!
 
-	@param[in] filename		Name of input file with float data.
+	@param[in] filename		Name of input file with double data.
 	@param[out] data		Data is written to this vector.
 */
-bool ReadFileToVector (char * filename, vector<float> & data);
+bool ReadFileToVector (char * filename, vector<double> & data);
 /*!
 	Writes indices of extrema features to file, sorted according to their persistence. 
 
@@ -60,7 +61,7 @@ void WriteMinMaxPairsToFile (char * filename, vector<TPairedExtrema> pairs);
 	Parses user command line.
 	Checks if the user set a threshold value or wants MATLAB indexing.
 */
-bool ParseCmdLine(int argc, char* argv[], float &threshold, bool & matlabIndexing);
+bool ParseCmdLine(int argc, char* argv[], double &threshold, bool & matlabIndexing);
 
 /*!
 	Main function - reads a file specified as a command line argument. runs persistence, 
@@ -72,9 +73,9 @@ bool ParseCmdLine(int argc, char* argv[], float &threshold, bool & matlabIndexin
 */
 int main(int argc, char* argv[])
 {
-	vector<float> data;
+	vector<double> data;
 	vector<int> indices; 
-	float threshold;
+	double threshold;
 	vector <TPairedExtrema> pairs;
 	bool matlabIndexing;
 	Persistence1D p;
@@ -115,7 +116,7 @@ int main(int argc, char* argv[])
 	return 0;
 }
 
-bool ReadFileToVector (char * filename, vector<float> & data)
+bool ReadFileToVector (char * filename, vector<double> & data)
 {
 	ifstream datafile;
 	
@@ -129,7 +130,7 @@ bool ReadFileToVector (char * filename, vector<float> & data)
 		return false;
 	}
 
-	float currdata;
+	double currdata;
 
 	while(datafile >> currdata)
 	{
@@ -152,13 +153,12 @@ void WriteMinMaxPairsToFile (char * filename, vector<TPairedExtrema> pairs)
 	
 	for (vector<TPairedExtrema>::iterator p = pairs.begin(); p != pairs.end(); p++)
 	{
-		datafile << to_string((long long)(*p).MinIndex) << endl;
-		datafile << to_string((long long)(*p).MaxIndex) << endl;
+		datafile << to_string((*p).MinIndex) << " " << to_string((*p).MaxIndex) << " " << to_string((*p).Persistence)<< endl;
 	}
 
 	datafile.close();
 }
-bool ParseCmdLine(int argc, char* argv[], float &threshold, bool & matlabIndexing)
+bool ParseCmdLine(int argc, char* argv[], double &threshold, bool & matlabIndexing)
 {	
 	bool noErrors = true;
 		
@@ -186,7 +186,7 @@ bool ParseCmdLine(int argc, char* argv[], float &threshold, bool & matlabIndexin
 		else if ( argv[counter][0] == '0') //different from nullptr
 		{
 			//this doesn't throw exceptions, AKAIK
-			threshold = (float)atof(argv[counter]);
+			threshold = (double)atof(argv[counter]);
 
 			//string begins with 0, 
 			//so it's ok that atof returns 0
@@ -202,7 +202,7 @@ bool ParseCmdLine(int argc, char* argv[], float &threshold, bool & matlabIndexin
 		else
 		{
 			//this doesn't throw exceptions, AKAIK
-			threshold = (float)atof(argv[counter]);
+			threshold = (double)atof(argv[counter]);
 
 			//the string does not include a 0, but atof returns 0. 
 			//string cannot be converted to threshold value
diff --git a/src/tests/tests.cpp b/src/tests/tests.cpp
index 259e0c3..4c5cd53 100644
--- a/src/tests/tests.cpp
+++ b/src/tests/tests.cpp
@@ -9,8 +9,8 @@ void SecondCallOnEmptyData()
 {
 	Persistence1D p;
 	vector<TPairedExtrema> pairs;
-	vector<int> min, max;
-	vector<float> data1, data2; 
+	vector<size_t> min, max;
+	vector<double> data1, data2; 
 
 	data1.push_back(1.0);
 	data1.push_back(2.0);
@@ -23,8 +23,8 @@ void SecondCallOnEmptyData()
 	p.RunPersistence(data2);
 	p.GetExtremaIndices(min, max);
 	p.GetPairedExtrema(pairs);
-	float minVal = p.GetGlobalMinimumValue();
-	int idx = p.GetGlobalMinimumIndex();
+	double minVal = p.GetGlobalMinimumValue();
+	size_t idx = p.GetGlobalMinimumIndex();
 	
 	assert(minVal==0);
 	assert(idx ==-1);
@@ -39,15 +39,15 @@ void MutliCallPersistence()
 {
 	Persistence1D p;
 	vector<TPairedExtrema> pairs;
-	vector<int> min, max;
-	vector<float> data1, data2; 
+	vector<size_t> min, max;
+	vector<double> data1, data2; 
 
 	data1.push_back(1.0);
 	data1.push_back(2.0);
 	data1.push_back(3.0);
 	data1.push_back(1.0);
 
-	data2 = vector<float>(data1);
+	data2 = vector<double>(data1);
 	data2.push_back(4.0);
 	data2.push_back(10.0);
 	data2.push_back(-5.0);
@@ -81,7 +81,7 @@ void MutliCallPersistence()
 
 	//now check the filters:
 	p.GetExtremaIndices(min, max, 10);
-	p.GetPairedExtrema(pairs, (float)2.1);
+	p.GetPairedExtrema(pairs, 2.1);
 	assert(p.GetGlobalMinimumValue()==-5.0);
 	assert(p.GetGlobalMinimumIndex()==6);
 	assert(min.size()==0);
@@ -96,8 +96,8 @@ void RunOnEmptyData()
 {
 	Persistence1D p;
 	vector<TPairedExtrema> pairs;
-	vector<int> min, max;
-	vector<float> data; 
+	vector<size_t> min, max;
+	vector<double> data; 
 
 	p.RunPersistence(data);
 
@@ -126,8 +126,8 @@ void CallsBeforeRuns()
 {
 	Persistence1D p;
 	vector<TPairedExtrema> pairs;
-	vector<int> min, max;
-	vector<float> data; 
+	vector<size_t> min, max;
+	vector<double> data; 
 
 	p.GetExtremaIndices(min, max);
 	assert(min.empty());
@@ -154,16 +154,16 @@ void TestInputSizeOne()
 {
 	Persistence1D p;
 	vector<TPairedExtrema> pairs;
-	vector<int> min, max;
+	vector<size_t> min, max;
 
-	vector<float> data; 
+	vector<double> data; 
 	data.push_back(10.0);
 
 	p.RunPersistence(data); 
 	p.GetPairedExtrema(pairs);
 	p.GetExtremaIndices(min, max);
-	int minIdx = p.GetGlobalMinimumIndex();
-	float minVal = p.GetGlobalMinimumValue();
+	size_t minIdx = p.GetGlobalMinimumIndex();
+	double minVal = p.GetGlobalMinimumValue();
 
 	assert(pairs.empty() && min.empty() && max.empty());
 	assert(minIdx==0);
@@ -177,17 +177,17 @@ void TestInputSizeTwo()
 {
 	Persistence1D p;
 	vector<TPairedExtrema> pairs;
-	vector<int> min, max;
+	vector<size_t> min, max;
 
-	vector<float> data; 
+	vector<double> data; 
 	data.push_back(10.0);
 	data.push_back(20.0);
 
 	p.RunPersistence(data); 
 	p.GetPairedExtrema(pairs);
 	p.GetExtremaIndices(min, max);
-	int minIdx = p.GetGlobalMinimumIndex();
-	float minVal = p.GetGlobalMinimumValue();
+	size_t minIdx = p.GetGlobalMinimumIndex();
+	double minVal = p.GetGlobalMinimumValue();
 
 	assert(pairs.empty() && min.empty() && max.empty());
 	assert(minIdx!=-1);
@@ -199,16 +199,16 @@ void TestInputSizeTwo()
 }
 void RandomizedTesting()
 {
-	vector<float> data; 
-	int size = rand() % 10000;
+	vector<double> data; 
+	size_t size = rand() % 10000;
 	data.reserve(size);
 
 	Persistence1D p;
 
 	//create data
-	for (int i = 0; i < size; i++)
+	for (size_t i = 0; i < size; i++)
 	{		
-		data.push_back((float)rand());
+		data.push_back((double)rand());
 	}
 
 	p.RunPersistence(data);
@@ -222,7 +222,7 @@ int main()
 	CallsBeforeRuns();
 	MutliCallPersistence();
 	SecondCallOnEmptyData();
-	for (int i = 0; i < 100; i++)
+	for (size_t i = 0; i < 100; i++)
 	{
 		RandomizedTesting();
 	}