diff --git a/MPI/MPI-OpenMP.c b/MPI/MPI-OpenMP.c
index 698e270a80ead79d38857589932b7660926da497..5fdfb6aea96f4e3fc6f5f663846cec71697a9cb5 100644
--- a/MPI/MPI-OpenMP.c
+++ b/MPI/MPI-OpenMP.c
@@ -12,29 +12,26 @@ int main(int argc, char ** argv) {
     int global_nm[2],local_nm[2]; //global matrix dimensions and local matrix dimensions (2D-domain, 2D-subdomain)
     int global_padded_nm[2];   //padded global matrix dimensions (if padding is not needed, global_padded=global)
     int i,j,k, sparse=0, *cooCol, n_z, *I;
-    MPI_Datatype dummy;     //dummy datatype used to align user-defined datatypes in memory
-    
-    double * M, * A, * x, * y, *local_y, * cooVal, comm_t, comp_t; //Global matrix, local current and previous matrices, pointer to swap between current and previous
+    double * M, * A, * x, * y, *local_y, * cooVal, comm_t, comp_t;
     
 	
     MPI_Init(&argc,&argv);
     MPI_Comm_size(MPI_COMM_WORLD,&size);
     MPI_Comm_rank(MPI_COMM_WORLD,&rank);
 	
-    /* Read n,m from stdin */
 	if (argc < 2) error("Too few Arguments");
-	else if ( argc == 2) /* ./Program Input_File */
+	else if ( argc == 2) /* ./Program Input_File -> File Input to COO */
 	{
 		if(!mtx_read(&I, &cooCol, &cooVal, &global_nm[0], &global_nm[1], &n_z, argv[1])) error("input and/or COO convertion failed");
 		sparse = 1;
 	}
-	else if ( argc == 3) { /*./Program N M */
+	else if ( argc == 3) { /*./Program N M -> Generate random NxM matrix */
         global_nm[0]=atoi(argv[1]);
         global_nm[1]=atoi(argv[2]);	
 	}
 	else error("Too many Arguments");
 
-	/* Padd n if needed */
+	/* Padd N if needed */
    	local_nm[1]=global_nm[1];
 	global_padded_nm[1]=global_nm[1];
 
@@ -76,8 +73,7 @@ int main(int argc, char ** argv) {
 		//printf( "Initialize data Thread=%d i=%d\n", omp_get_thread_num(), i);
 	}
 
-    //----Rank 0 scatters the global matrix----//
-
+    /* Rank 0 scatters the global matrix */
 	double * gsendbuf;
 	if (rank == 0){
 		gsendbuf = &(M[0]);
@@ -103,14 +99,14 @@ int main(int argc, char ** argv) {
         	local_y[k] = yi;
     	}
 	}
+
 	MPI_Barrier(MPI_COMM_WORLD);
 	if (rank==0) comp_t= MPI_Wtime() - comp_t;
-
 	MPI_Gather(local_y, local_nm[0], MPI_DOUBLE, y, local_nm[0], MPI_DOUBLE, 0, MPI_COMM_WORLD);
-	//MPI_Reduce(local_y, y, global_nm[0], MPI_DOUBLE, MPI_SUM, 0, MPI_COMM_WORLD);
-
 	if (rank==0) comm_t = MPI_Wtime() - comm_t - comp_t;
-#ifdef _DEBUG_ /* Output y in a file for debug purposes */
+
+#ifdef _DEBUG_
+	/* Output y vector to a file for debugging */
 	if (rank == 0) {
         FILE * fp;
 		char * filename = "/users/guest/petyros/Training/Outputs/Debug/MPI-OpenMP.out" ;
diff --git a/MPI/MPI.c b/MPI/MPI.c
index acafc497348aae8bc6514d1ac68840ed457e9db1..91333a239f7e8480fc9f0f310ffcf8d88c085441 100644
--- a/MPI/MPI.c
+++ b/MPI/MPI.c
@@ -12,29 +12,26 @@ int main(int argc, char ** argv) {
     int global_nm[2],local_nm[2]; //global matrix dimensions and local matrix dimensions (2D-domain, 2D-subdomain)
     int global_padded_nm[2];   //padded global matrix dimensions (if padding is not needed, global_padded=global)
     int i,j,k, sparse=0, *cooCol, n_z, *I;
-    MPI_Datatype dummy;     //dummy datatype used to align user-defined datatypes in memory
-    
-    double * M, * A, * x, * y, *local_y, * cooVal, comm_t, comp_t; //Global matrix, local current and previous matrices, pointer to swap between current and previous
+    double * M, * A, * x, * y, *local_y, * cooVal, comm_t, comp_t;
     
 	
     MPI_Init(&argc,&argv);
     MPI_Comm_size(MPI_COMM_WORLD,&size);
     MPI_Comm_rank(MPI_COMM_WORLD,&rank);
 	
-    /* Read n,m from stdin */
 	if (argc < 2) error("Too few Arguments");
-	else if ( argc == 2) /* ./Program Input_File */
+	else if ( argc == 2) /* ./Program Input_File -> File Input to COO */
 	{
 		if(!mtx_read(&I, &cooCol, &cooVal, &global_nm[0], &global_nm[1], &n_z, argv[1])) error("input and/or COO convertion failed");
 		sparse = 1;
 	}
-	else if ( argc == 3) { /*./Program N M */
+	else if ( argc == 3) { /*./Program N M -> Generate random NxM matrix */
         global_nm[0]=atoi(argv[1]);
         global_nm[1]=atoi(argv[2]);	
 	}
 	else error("Too many Arguments");
 
-	/* Padd n if needed */
+	/* Padd N if needed */
    	local_nm[1]=global_nm[1];
 	global_padded_nm[1]=global_nm[1];
 
@@ -70,8 +67,7 @@ int main(int argc, char ** argv) {
 
 	A = (double *) malloc(local_nm[0] * local_nm[1] * sizeof(*M));
 
-    //----Rank 0 scatters the global matrix----//
-
+    /* Rank 0 scatters the global matrix */
 	double * gsendbuf;
 	if (rank == 0){
 		gsendbuf = &(M[0]);
@@ -96,14 +92,14 @@ int main(int argc, char ** argv) {
         	local_y[k] = yi;
     	}
 	}
+
 	MPI_Barrier(MPI_COMM_WORLD);
 	if (rank==0) comp_t= MPI_Wtime() - comp_t;
-
 	MPI_Gather(local_y, local_nm[0], MPI_DOUBLE, y, local_nm[0], MPI_DOUBLE, 0, MPI_COMM_WORLD);
-	//MPI_Reduce(local_y, y, global_nm[0], MPI_DOUBLE, MPI_SUM, 0, MPI_COMM_WORLD);
-
 	if (rank==0) comm_t = MPI_Wtime() - comm_t - comp_t;
-#ifdef _DEBUG_ /* Output y in a file for debug purposes */
+
+#ifdef _DEBUG_ 
+	/* Output y vector to a file for debugging */
 	if (rank == 0) {
         FILE * fp;
 		char * filename = "/users/guest/petyros/Training/Outputs/Debug/MPI.out" ;
diff --git a/OpenMP/OpenMP.c b/OpenMP/OpenMP.c
index d4311e11162498eb0dfc36de7c2998b7acfba05a..964c7617a63e389cba16f154a5efad3233aeaefd 100644
--- a/OpenMP/OpenMP.c
+++ b/OpenMP/OpenMP.c
@@ -21,20 +21,19 @@ int main(int argc, char **argv)
 	int *I, *cooCol, n_z, sparse=0;
 	double *cooVal, timer;
 
-
-	/* File Input to COO */
 	if (argc < 2) error("Too few Arguments");
-	else if ( argc == 2) /* ./Program Input_File */
+	else if ( argc == 2) /* ./Program Input_File -> File Input to COO */
 	{
 		if(!mtx_read(&I, &cooCol, &cooVal, &n, &m, &n_z, argv[1])) error("input and/or COO convertion failed");
 		sparse = 1;
 	}
-	else if ( argc == 3) { /*./Program N M */
+	else if ( argc == 3) { /*./Program N M -> Generate random NxM matrix */
 		n = atoi(argv[1]);
 		m = atoi(argv[2]);		
 	}
 	else error("Too many Arguments");
 
+	/* Allocate space */
 	double *x 			= (double *) malloc(m * sizeof(*x));
 	double *y	= (double *) malloc(n * sizeof(*y));
 	double **M 			= (double **) malloc(n * sizeof(*M));
@@ -65,13 +64,16 @@ int main(int argc, char **argv)
     	}
 	}
 	timer = csecond() - timer;
+
 #ifdef _DEBUG_
-        		FILE * fp;
-				char * filename = "/users/guest/petyros/Training/Outputs/Debug/OpenMP.out" ;
-				if(( fp = fopen( filename, "w")) == NULL)  error("Output file creation failed\n");
-        		for (k = 0; k < n; ++k) fprintf(fp, "%lf ", y[k]) ;
-				fclose(fp) ;
+	/* Output y vector to a file for debugging */
+    FILE * fp;
+	char * filename = "/users/guest/petyros/Training/Outputs/Debug/OpenMP.out" ;
+	if(( fp = fopen( filename, "w")) == NULL)  error("Output file creation failed\n");
+    for (k = 0; k < n; ++k) fprintf(fp, "%lf ", y[k]) ;
+	fclose(fp) ;
 #endif
+
 	report_results(timer);
 
 
diff --git a/OpenMP/OpenMP_aff.c b/OpenMP/OpenMP_aff.c
index e25d9bf3a9e16b003bc629030448b06c977d448a..a5dd2648c99762224c759f5428b3ed735f4cb392 100644
--- a/OpenMP/OpenMP_aff.c
+++ b/OpenMP/OpenMP_aff.c
@@ -20,25 +20,24 @@ int main(int argc, char **argv)
 	int *I, *cooCol, n_z, sparse=0;
 	double *cooVal, timer;
 
-
-	/* File Input to COO */
 	if (argc < 2) error("Too few Arguments");
-	else if ( argc == 2) /* ./Program Input_File */
+	else if ( argc == 2) /* ./Program Input_File -> File Input to COO */
 	{
 		if(!mtx_read(&I, &cooCol, &cooVal, &n, &m, &n_z, argv[1])) error("input and/or COO convertion failed");
 		sparse = 1;
 	}
-	else if ( argc == 3) { /*./Program N M */
+	else if ( argc == 3) { /*./Program N M -> Generate random NxM matrix */
 		n = atoi(argv[1]);
 		m = atoi(argv[2]);		
 	}
 	else error("Too many Arguments");
 
+	/* Allocate space */
 	double *x 			= (double *) malloc(m * sizeof(*x));
 	double *y	= (double *) malloc(n * sizeof(*y));
 	double *M 			= (double *) malloc(n * m * sizeof(*M));
 
-	#pragma omp parallel for schedule(static) /* Initialize data for each thread in corresponding socket with first-touch policy */
+	#pragma omp parallel for schedule(static) /* Initialize data for each thread in corresponding socket/cache with first-touch policy */
 	for( i=0 ; i<n ; ++i){
 		for ( j=0 ; j<m ; ++j) M[i*m+j]=0.0;	
 		//printf( "Initialize data Thread=%d i=%d\n", omp_get_thread_num(), i);
@@ -58,8 +57,8 @@ int main(int argc, char **argv)
 	vec_init(y, n, 0.0);
 	
 
-	/* OpenMP Kernel */
-	printf("OpenMP Version(N=%d, M=%d, Threads=%s): ", n, m, getenv("OMP_NUM_THREADS"));
+	/* OpenMP Affinity Kernel */
+	printf("OpenMP_aff Version(N=%d, M=%d, Threads=%s): ", n, m, getenv("OMP_NUM_THREADS"));
 	timer = csecond();
 	for (i = 0; i < NR_ITER; ++i){
 		register double	yi = 0;
@@ -72,13 +71,16 @@ int main(int argc, char **argv)
     	}
 	}
 	timer = csecond() - timer;
-#ifdef _DEBUG_ /* Output y in a file for debug purposes */
-        		FILE * fp;
-				char * filename = "/users/guest/petyros/Training/Outputs/Debug/OpenMP_aff.out" ;
-				if(( fp = fopen( filename, "w")) == NULL)  error("Output file creation failed\n");
-        		for (k = 0; k < n; ++k) fprintf(fp, "%lf ", y[k]) ;
-				fclose(fp) ;
+
+#ifdef _DEBUG_ 
+	/* Output y vector to a file for debugging */
+	FILE * fp;
+	char * filename = "/users/guest/petyros/Training/Outputs/Debug/OpenMP_aff.out" ;
+	if(( fp = fopen( filename, "w")) == NULL)  error("Output file creation failed\n");
+	for (k = 0; k < n; ++k) fprintf(fp, "%lf ", y[k]) ;
+	fclose(fp) ;
 #endif
+
 	report_results(timer);
 
 	return 0;
diff --git a/Serial/Serial.c b/Serial/Serial.c
index 55fb63038f1979c1894e0778d51a6c25dc6d2f5e..33ad15c17f7ee0acc54787693e0b48680a41dfa1 100644
--- a/Serial/Serial.c
+++ b/Serial/Serial.c
@@ -20,22 +20,22 @@ int main(int argc, char **argv)
 	double *cooVal, timer;
 
 
-	/* File Input to COO */
 	if (argc < 2) error("Too few Arguments");
-	else if ( argc == 2) /* ./Program Input_File */
+	else if ( argc == 2) /* ./Program Input_File -> File Input to COO */
 	{
 		if(!mtx_read(&I, &cooCol, &cooVal, &n, &m, &n_z, argv[1])) error("input and/or COO convertion failed");
 		sparse = 1;
 	}
-	else if ( argc == 3) { /*./Program N M */
+	else if ( argc == 3) { /*./Program N M -> Generate random NxM matrix */
 		n = atoi(argv[1]);
 		m = atoi(argv[2]);		
 	}
 	else error("Too many Arguments");
-
-	double *x 			= (double *) malloc(m * sizeof(*x));
+	
+	/* Allocate space */
+	double *x 	= (double *) malloc(m * sizeof(*x));
 	double *y	= (double *) malloc(n * sizeof(*y));
-	double **M 			= (double **) malloc(n * sizeof(*M));
+	double **M 	= (double **) malloc(n * sizeof(*M));
 	for( i=0 ; i<n ; ++i) M[i] = (double *) calloc(m, sizeof(double));
 	if( !y || !x || !M ) error("memory allocation failed");
 
@@ -62,13 +62,16 @@ int main(int argc, char **argv)
     	}
 	}
 	timer = csecond() - timer ;
+
 #ifdef _DEBUG_
-        		FILE * fp;
-				char * filename = "/users/guest/petyros/Training/Outputs/Debug/Serial.out" ;
-				if(( fp = fopen( filename, "w")) == NULL)  error("Output file creation failed\n");
-        		for (k = 0; k < n; ++k) fprintf(fp, "%lf ", y[k]) ;
-				fclose(fp) ;
+	/* Output y vector to a file for debugging */
+	FILE * fp;
+	char * filename = "/users/guest/petyros/Training/Outputs/Debug/Serial.out" ;
+	if(( fp = fopen( filename, "w")) == NULL)  error("Output file creation failed\n");
+	for (k = 0; k < n; ++k) fprintf(fp, "%lf ", y[k]) ;
+	fclose(fp) ;
 #endif
+
 	report_results(timer);
 
 	return 0;