diff --git a/main.cu b/main.cu
index cd00c21..a3a7e87 100644
--- a/main.cu
+++ b/main.cu
@@ -14,6 +14,11 @@
 #include <stim/parser/arguments.h>
 #include <stim/visualization/camera.h>
 
+#ifdef __CUDACC__
+//CUDA includes
+#include <cuda.h>
+#endif
+
 //ANN includes
 //#include <ANN/ANN.h>
 
@@ -29,9 +34,9 @@ stim::gl_network<float> GT;			//ground truth network
 stim::gl_network<float> T;			//test network
 
 //hard-coded parameters
-float resample_rate = 0.5;			//sample rate for the network (fraction of sigma used as the maximum sample rate)
-float camera_factor = 1.2;			//start point of the camera as a function of X and Y size
-float orbit_factor = 0.01;			//degrees per pixel used to orbit the camera
+float resample_rate = 0.5f;			//sample rate for the network (fraction of sigma used as the maximum sample rate)
+float camera_factor = 1.2f;			//start point of the camera as a function of X and Y size
+float orbit_factor = 0.01f;			//degrees per pixel used to orbit the camera
 
 //mouse position tracking
 int mouse_x;
@@ -195,11 +200,26 @@ void glut_initialize(){
 	cam.LookAt(c[0], c[1], c[2]);						//look at the center of the network
 }
 
+#ifdef __CUDACC__
+void setdevice(int &device){
+	int count;
+	cudaGetDeviceCount(&count);				// numbers of device that are available
+	if(count < device + 1){
+	std::cout<<"No such device available, please set another device"<<std::endl;
+	exit(1);
+	}
+}
+#else
+void setdevice(int &device){
+	device = -1;
+}
+#endif
+
 //compare both networks and fill the networks with error information
-void compare(float sigma){
+void compare(float sigma, int device){
 
-	GT = GT.compare(T, sigma);						//compare the ground truth to the test case - store errors in GT
-    T = T.compare(GT, sigma);						//compare the test case to the ground truth - store errors in T
+	GT = GT.compare(T, sigma, device);						//compare the ground truth to the test case - store errors in GT
+    T = T.compare(GT, sigma, device);						//compare the test case to the ground truth - store errors in T
 
 	//calculate the metrics
 	float FPR = GT.average(1);						//calculate the metrics
@@ -212,7 +232,7 @@ void compare(float sigma){
 // writes features of the networks i.e average segment length, tortuosity, branching index, contraction, fractal dimension, number of end and branch points to a csv file
 // Pranathi wrote this - saves network features to a CSV file
 void features(std::string filename){
-			double avgL_t, avgL_gt, avgT_t, avgT_gt, avgB_t, avgB_gt, avgC_t, avgC_gt, avgFD_t, avgFD_gt;
+		double avgL_t, avgL_gt, avgT_t, avgT_gt, avgB_t, avgB_gt, avgC_t, avgC_gt, avgFD_t, avgFD_gt;
 		unsigned int e_t, e_gt, b_gt, b_t;
 		avgL_gt = GT.Lengths();
 		avgT_gt = GT.Tortuosities();
@@ -246,10 +266,12 @@ void advertise(){
 	std::cout<<"Source: https://git.stim.ee.uh.edu/segmentation/netmets"<<std::endl;
 	std::cout<<"========================================================================="<<std::endl<<std::endl;
 
-	std::cout<<"usage: netmets file1 file2 --sigma 10"<<std::endl;
-	std::cout<<"            compare two files with a tolerance of 10 (units defined by the network)"<<std::endl;
-	std::cout<<"       netmets file1 --gui"<<std::endl<<std::endl;
-	std::cout<<"            load a file and display it using OpenGL"<<std::endl;
+	std::cout<<"usage: netmets file1 file2 --sigma 3"<<std::endl;
+	std::cout<<"            compare two files with a tolerance of 3 (units defined by the network)"<<std::endl<<std::endl;
+	std::cout<<"       netmets file1 --gui"<<std::endl;
+	std::cout<<"            load a file and display it using OpenGL"<<std::endl<<std::endl;
+	std::cout<<"       netmets file1 file2 --device 0"<<std::endl;
+	std::cout<<"            compare two files using device 0 (if there isn't a gpu, use cpu)"<<std::endl<<std::endl;
 }
 
 int main(int argc, char* argv[])
@@ -258,8 +280,9 @@ int main(int argc, char* argv[])
 
 	//add arguments
 	args.add("help", "prints this help");
-	args.add("sigma", "force a sigma value to specify the tolerance of the network comparison", "10");
+	args.add("sigma", "force a sigma value to specify the tolerance of the network comparison", "3");
 	args.add("gui", "display the network or network comparison using OpenGL");
+	args.add("device", "choose specific device to run", "0");
 	args.add("features", "save features to a CSV file, specify file name");
 
 	args.parse(argc, argv);					//parse the user arguments
@@ -277,6 +300,7 @@ int main(int argc, char* argv[])
 	}
 	
 	if(args.nargs() == 2){			//if two files are specified, they will be displayed in neighboring viewports and compared
+		int device = args["device"].as_int();				//get the device value from the user
 		num_nets = 2;										//set the number of networks to two
 		float sigma = args["sigma"].as_float();				//get the sigma value from the user
 		T.load_obj(args.arg(1));                           //load the second (test) network
@@ -284,7 +308,8 @@ int main(int argc, char* argv[])
 			features(args["features"].as_string());
 		GT = GT.resample(resample_rate * sigma);			//resample both networks based on the sigma value
 		T = T.resample(resample_rate * sigma);
-		compare(sigma);										//run the comparison algorithm
+		setdevice(device);
+		compare(sigma, device);										//run the comparison algorithm
 	}
 
 	//if a GUI is requested, display the network using OpenGL
--
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