From 0384735eb3b858166d09116e00c237347b9ccb36 Mon Sep 17 00:00:00 2001
From: Ilnur Yakupov <yakupnk@gmail.com>
Date: Fri, 16 Sep 2016 22:20:22 +0300
Subject: [PATCH] openmp

---
 openmp.cpp   | 20 ++++++++++++++++++--
 piopenmp.cpp | 24 ++++++++++++++++++++++++
 2 files changed, 42 insertions(+), 2 deletions(-)
 create mode 100644 piopenmp.cpp

diff --git a/openmp.cpp b/openmp.cpp
index ac42f84..4141dbb 100644
--- a/openmp.cpp
+++ b/openmp.cpp
@@ -5,11 +5,14 @@
 #include <cstdlib>
 #include <ctime>
 #include <algorithm>
+#include <omp.h>
+#include <time.h>
 
 //Matrix multiplication    
 int main(int argc, char *argv[])
 {
     int n = 1024;
+    time_t startTime,endTime;
 
     std::vector<double> a(n*n);
     std::vector<double> b(n*n);
@@ -20,10 +23,23 @@ int main(int argc, char *argv[])
     std::generate(a.begin(), a.end(), std::rand);
     std::generate(b.begin(), b.end(), std::rand);
 
+    time (&startTime);
     for(int i = 0; i < n; ++i)
         for(int j = 0; j < n; ++j)
             for(int k = 0; k < n; ++k)
                 c[i*n + j] += a[i*n + k] * b[k*n + j];
-	
+   
+    time (&endTime); 
+    std::cout << difftime (endTime,startTime) << std::endl;
+
+    time (&startTime);
+    #pragma omp parallel for
+    for(int i = 0; i < n; ++i)
+        for(int j = 0; j < n; ++j)
+            for(int k = 0; k < n; ++k)
+                c[i*n + j] += a[i*n + k] * b[k*n + j];
+   
+    time (&endTime); 
+    std::cout << difftime (endTime,startTime) << std::endl;
     return 0;
-}
+}
\ No newline at end of file
diff --git a/piopenmp.cpp b/piopenmp.cpp
new file mode 100644
index 0000000..42e1434
--- /dev/null
+++ b/piopenmp.cpp
@@ -0,0 +1,24 @@
+#include <iostream>
+#include <fstream>
+#include <sstream>
+#include <vector>
+#include <cstdlib>
+#include <ctime>
+#include <algorithm>
+#include <omp.h>
+
+double f(double x){
+    return 4/(1+x*x);
+}
+
+int main(int argc, char *argv[]){
+    int n = 10240;
+    double s;
+    #pragma omp parallel for reduction(+:s) 
+    for(int i = 1; i <= n; i++)
+        s += f((i - 0.5)/n);
+    double pi = s/n;
+   
+    std::cout << pi << std::endl;
+    return 0;
+}
\ No newline at end of file