test01.cpp

#include <iostream>
#include <cmath>
#include <ctime>
#include <ratio>
#include <chrono>

/*
Compile:   g++ --std=c++14 test01.cpp -o test01 
Run:       ./test01
*/


// function to add the elements of two arrays
static void add(int n, float *x, float *y){
	for (int i = 0; i < n; i++)
		y[i] = x[i] + y[i];
}

int main(void){
	using namespace std::chrono;
	int N = 1<<24; // 1M elements

	float *x = new float[N];
	float *y = new float[N];

	// initialize x and y arrays on the host
	for (int i = 0; i < N; i++) {
		x[i] = 1.0f;
		y[i] = 2.0f;
	}

	high_resolution_clock::time_point t1 = high_resolution_clock::now();

  

	// Run kernel on 1M elements on the CPU
	add(N, x, y);

	high_resolution_clock::time_point t2 = high_resolution_clock::now();

	// Check for errors (all values should be 3.0f)
	float maxError = 0.0f;
	for (int i = 0; i < N; i++)
		maxError = fmax(maxError, fabs(y[i]-3.0f));

	duration<double> time_span = duration_cast<duration<double>>(t2 - t1);

	
	std::cout << "Max error: " << maxError << "\n";
	std::cout << "Duration: " << time_span.count() * 1000 << " ms\n";
	// Free memory
	delete [] x;
	delete [] y;

	return 0;
}