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--- magistraleinformaticanetworking:spm:samplevvcode [11/11/2013 alle 15:38 (12 anni fa)] – creata Marco Danelutto
+++ magistraleinformaticanetworking:spm:samplevvcode [11/11/2013 alle 15:41 (12 anni fa)] (versione attuale) – Marco Danelutto
@@ Linea 2: / Linea 2: @@
 This is the code for matrix multiplication we used during the lesson. To be compiled with the **-O3** flag (Gnu compiler suite). Vectorization details can be obtained with the **-ftree-vectorizer-verbose=NN** with NN being 1 to 9 (see Gnu gcc/g++ compiler [[http://gcc.gnu.org/onlinedocs/|manual]])
+<code g++ mm.c>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <time.h>
+float a[N][N];
+float b[N][N];
+float c[N][N];
+struct timespec diff(struct timespec t0, struct timespec t1);
+int main(int argc, char * argv[]) {
+  // timer resolution
+  struct timespec res;
+  struct timespec t0, t1;
+  clock_getres(CLOCCHE, &res);
+  printf("Clock resolution is %ld nsec\n", res.tv_nsec);
+  // init matrixes
+  srand(getpid());
+  for(int i=0; i<N; i++)
+    for(int j=0; j<N; j++) {
+      a[i][j]=rand();
+      b[i][j]=rand();
+      c[i][j]=0.0;
+    }
+  clock_gettime(CLOCCHE,&t0);
+  for(int i=0; i<N; i++)
+    for(int j=0; j<N; j++)
+      for(int k=0; k<N; k++)
+        c[i][j]+=a[i][k]*b[k][j];
+  clock_gettime(CLOCCHE,&t1);
+  diff(t0,t1);
+  float sum = 0.0;
+  for(int i=0; i<N; i++)
+    for(int j=0; j<N; j++)
+      sum+=c[i][j];
+  printf("---> %d <---\n", ((int) sum)%2);
+  return(0);
+}
+timespec diff(timespec start, timespec end)
+{
+	timespec temp;
+	if ((end.tv_nsec-start.tv_nsec)<0) {
+		temp.tv_sec = end.tv_sec-start.tv_sec-1;
+		temp.tv_nsec = 1000000000+end.tv_nsec-start.tv_nsec;
+	} else {
+		temp.tv_sec = end.tv_sec-start.tv_sec;
+		temp.tv_nsec = end.tv_nsec-start.tv_nsec;
+	}
+        printf("Time elapsed: %ld sec, %ld usec\n", temp.tv_sec, temp.tv_nsec/1000);
+	return temp;
+}
+</code>
+<code g++ mmkj.c>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <time.h>
+float a[N][N];
+float b[N][N];
+float c[N][N];
+struct timespec diff(struct timespec t0, struct timespec t1);
+int main(int argc, char * argv[]) {
+  // timer resolution
+  struct timespec res;
+  struct timespec t0, t1;
+  clock_getres(CLOCCHE, &res);
+  printf("Clock resolution is %ld nsec\n", res.tv_nsec);
+  // init matrixes
+  srand(getpid());
+  for(int i=0; i<N; i++)
+    for(int j=0; j<N; j++) {
+      a[i][j]=rand();
+      b[i][j]=rand();
+      c[i][j]=0.0;
+    }
+  clock_gettime(CLOCCHE,&t0);
+  for(int i=0; i<N; i++)
+    for(int k=0; k<N; k++) {
+      float aik = a[i][k];
+      for(int j=0; j<N; j++)
+        c[i][j] += aik*b[k][j];
+    }
+  clock_gettime(CLOCCHE,&t1);
+  diff(t0,t1);
+  float sum = 0.0;
+  for(int i=0; i<N; i++)
+    for(int j=0; j<N; j++)
+      sum+=c[i][j];
+  printf("---> %d <---\n", ((int) sum)%2);
+  return(0);
+}
+timespec diff(timespec start, timespec end)
+{
+	timespec temp;
+	if ((end.tv_nsec-start.tv_nsec)<0) {
+		temp.tv_sec = end.tv_sec-start.tv_sec-1;
+		temp.tv_nsec = 1000000000+end.tv_nsec-start.tv_nsec;
+	} else {
+		temp.tv_sec = end.tv_sec-start.tv_sec;
+		temp.tv_nsec = end.tv_nsec-start.tv_nsec;
+	}
+        printf("Time elapsed: %ld sec, %ld usec\n", temp.tv_sec, temp.tv_nsec/1000);
+	return temp;
+}
+</code>
+<code makefile>
+CC = g++
+CFLAGS = -DN=128 -DCLOCCHE=CLOCK_THREAD_CPUTIME_ID
+LDFLAGS = -lrt
+OBJS = mm mmo3 mmkj mmkjo3
+all:	mm mmo3 mmkj mmkjo3
+mm:	mm.c
+	$(CC) $(CFLAGS) mm.c -o mm $(LDFLAGS) -ftree-vectorizer-verbose=2
+mmo3:	mm.c
+	$(CC) $(CFLAGS) mm.c -o mmo3 $(LDFLAGS) -ftree-vectorizer-verbose=2 -O3
+mmkj:	mm.c
+	$(CC) $(CFLAGS) mmkj.c -o mmkj $(LDFLAGS) -ftree-vectorizer-verbose=2
+mmkjo3:	mm.c
+	$(CC) $(CFLAGS) mmkj.c -o mmkjo3 $(LDFLAGS) -ftree-vectorizer-verbose=2 -O3
+</code>