From 377278e859785d56a8b21e5c200175390f6a645e Mon Sep 17 00:00:00 2001
From: Orestis <orestis.malaspinas@pm.me>
Date: Wed, 27 Oct 2021 10:39:33 +0200
Subject: [PATCH] added sum code to measure CPU time
---
source_codes/complexity/.gitignore | 1 +
source_codes/complexity/Makefile | 18 ++++++++++++++
source_codes/complexity/sum.c | 39 ++++++++++++++++++++++++++++++
3 files changed, 58 insertions(+)
create mode 100644 source_codes/complexity/.gitignore
create mode 100644 source_codes/complexity/Makefile
create mode 100644 source_codes/complexity/sum.c
diff --git a/source_codes/complexity/.gitignore b/source_codes/complexity/.gitignore
new file mode 100644
index 0000000..9229287
--- /dev/null
+++ b/source_codes/complexity/.gitignore
@@ -0,0 +1 @@
+sum
diff --git a/source_codes/complexity/Makefile b/source_codes/complexity/Makefile
new file mode 100644
index 0000000..d7822ac
--- /dev/null
+++ b/source_codes/complexity/Makefile
@@ -0,0 +1,18 @@
+CC:=gcc
+# SAN:=-fsanitize=address
+CFLAGS:=-Wall -Wextra -pedantic -g $(SAN)
+LDFLAGS:=-lm $(SAN)
+
+EXECS := $(shell find . -type f -iname '*.c' | sed 's/\.c//g')
+
+all: $(EXECS)
+
+$(EXECS): %: %.c
+ $(CC) $(CFLAGS) -o $@ $< $(LDFLAGS)
+ @echo $@ >> .gitignore
+
+.PHONY: clean all
+
+clean:
+ rm -f *.o $(EXECS) .gitignore
+
diff --git a/source_codes/complexity/sum.c b/source_codes/complexity/sum.c
new file mode 100644
index 0000000..4451354
--- /dev/null
+++ b/source_codes/complexity/sum.c
@@ -0,0 +1,39 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+#define SIZE 1000000
+#define NUM_TIMES 10
+
+void init(int n, double tab[]) {
+ for (int i = 0; i < n; ++i) {
+ tab[i] = (double)rand() / (double)RAND_MAX;
+ }
+}
+
+double sum(int n, double tab[]) {
+ double s = tab[0];
+ for (int i = 1; i < n; ++i) {
+ s += tab[i] * tab[i] * tab[i] * tab[i];
+ }
+ return s;
+}
+
+int main() {
+ double tab[SIZE];
+ init(SIZE, tab);
+
+ struct timespec tstart = {0, 0}, tend = {0, 0};
+ clock_gettime(CLOCK_MONOTONIC, &tstart);
+ double s = 0;
+ for (int i = 0; i < NUM_TIMES; ++i) {
+ s += sum(SIZE, tab);
+ }
+ clock_gettime(CLOCK_MONOTONIC, &tend);
+ printf("the computation of %f took about %.5f seconds\n", s,
+ (((double)tend.tv_sec + 1e-9 * tend.tv_nsec) -
+ ((double)tstart.tv_sec + 1e-9 * tstart.tv_nsec)) /
+ NUM_TIMES);
+
+ return 0;
+}
--
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