57 lines
1.2 KiB
C++
57 lines
1.2 KiB
C++
|
#include "walltime.h"
|
||
|
|
#include <iostream>
|
||
|
|
#include <random>
|
||
|
|
|
||
|
|
#define VEC_SIZE 1000000000
|
||
|
|
#define BINS 16
|
||
|
|
|
||
|
|
using namespace std;
|
||
|
|
|
||
|
|
int main() {
|
||
|
|
double time_start, time_end;
|
||
|
|
|
||
|
|
// Initialize random number generator
|
||
|
|
unsigned int seed = 123;
|
||
|
|
float mean = BINS / 2.0;
|
||
|
|
float sigma = BINS / 12.0;
|
||
|
|
std::default_random_engine generator(seed);
|
||
|
|
std::normal_distribution<float> distribution(mean, sigma);
|
||
|
|
|
||
|
|
// Generate random sequence
|
||
|
|
// Note: normal distribution is on interval [-inf; inf]
|
||
|
|
// we want [0; BINS-1]
|
||
|
|
int *vec = new int[VEC_SIZE];
|
||
|
|
for (long i = 0; i < VEC_SIZE; ++i) {
|
||
|
|
vec[i] = int(distribution(generator));
|
||
|
|
if (vec[i] < 0)
|
||
|
|
vec[i] = 0;
|
||
|
|
if (vec[i] > BINS - 1)
|
||
|
|
vec[i] = BINS - 1;
|
||
|
|
}
|
||
|
|
|
||
|
|
// Initialize histogram
|
||
|
|
// Set all bins to zero
|
||
|
|
long dist[BINS];
|
||
|
|
for (int i = 0; i < BINS; ++i) {
|
||
|
|
dist[i] = 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
time_start = wall_time();
|
||
|
|
|
||
|
|
// TODO Parallelize the histogram computation
|
||
|
|
for (long i = 0; i < VEC_SIZE; ++i) {
|
||
|
|
dist[vec[i]]++;
|
||
|
|
}
|
||
|
|
time_end = wall_time();
|
||
|
|
|
||
|
|
// Write results
|
||
|
|
for (int i = 0; i < BINS; ++i) {
|
||
|
|
cout << "dist[" << i << "]=" << dist[i] << endl;
|
||
|
|
}
|
||
|
|
cout << "Time: " << time_end - time_start << " sec" << endl;
|
||
|
|
|
||
|
|
delete[] vec;
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|