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QuickSort_Parallell.c
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QuickSort_Parallell.c
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//==================================================//
// SEQUENTIAL QUICK SORT //
//==================================================//
#include <stdio.h>
#include <stdlib.h>
#include <mpi.h>
#include <omp.h>
#include <time.h>
#define ITEMS 2048*2048
#define DEBUG 0
static int* v;
static int* sorted;
static void InitArray(void);
static void QuickSort(int*, unsigned, unsigned);
static unsigned Partition(int*, unsigned, unsigned, unsigned);
static void Swap(int*, unsigned, unsigned);
static void PrintArray(void);
static void CleanMemory(void);
int main(int argc, char **argv)
{
MPI_Init(&argc, &argv);
double start_time, end_time;
// Print some info
omp_set_nested(1);
int maxThreads = omp_get_max_threads();
printf("Available threads: %d\n", maxThreads);
// Initialize the array.
InitArray();
// Print data if in debug mode.
if (DEBUG)
{
printf("===== BEFORE QUICK SORT (SEQ) =====\n\n");
PrintArray();
printf("===================================\n\n\n");
}
// Start timer.
start_time = MPI_Wtime();
// Split into 8 pieces and sort
int subArraySize = ITEMS / maxThreads;
int maxInd = ((maxThreads - 1) * subArraySize) - 1 + subArraySize;
int i;
#pragma omp parallel for
for (i = 0; i < maxThreads; i++)
{
QuickSort(v, i * subArraySize, (i * subArraySize) - 1 + subArraySize);
}
// Sort the pieces
int j;
for (i = 0; i < ITEMS / maxThreads; i++)
{
for (j = 0; j < maxThreads; j++)
{
sorted[maxThreads * i + j] = v[subArraySize * j + i];
}
}
#pragma omp parallel for
for (i = 0; i < subArraySize; i++)
{
QuickSort(sorted, i * maxThreads, i * maxThreads + maxThreads - 1);
}
// Stop timer.
end_time = MPI_Wtime();
// Print data if in debug mode.
if (DEBUG)
{
printf("===== AFTER QUICK SORT (SEQ) ======\n\n");
PrintArray();
printf("===================================\n\n");
}
else
{
printf("Lowest: %d\n", sorted[0]);
printf("Highest: %d\n", sorted[ITEMS - 1]);
}
double time_taken = (end_time - start_time);
printf("Execution time: %fs\n", time_taken);
CleanMemory();
}
// Initialization of array.
static void InitArray(void)
{
//srand(time(0));
int i;
v = (int*)malloc(ITEMS * sizeof(int));
sorted = malloc(ITEMS * sizeof(int));
for (i = 0; i < ITEMS; i++)
{
v[i] = rand();
}
}
static void CleanMemory(void)
{
free(v);
free(sorted);
}
// Sorting function.
static void QuickSort(int *v, unsigned low, unsigned high)
{
unsigned pivot_index;
// No need to sort a vector of zero or one element.
if (low >= high)
{
return;
}
// Select the pivot value.
pivot_index = (low + high) / 2;
// Partition the array.
pivot_index = Partition(v, low, high, pivot_index);
// Sort the two sub arrays.
if (low < pivot_index)
{
QuickSort(v, low, (pivot_index - 1));
}
if (pivot_index < high)
{
QuickSort(v, (pivot_index + 1), high);
}
}
// Array partitioning function.
static unsigned Partition(int *v, unsigned low, unsigned high, unsigned pivot_index)
{
// Move pivot to the bottom of the vector.
if (pivot_index != low)
{
Swap(v, low, pivot_index);
}
pivot_index = low;
low++;
// Move elements into place.
while (low <= high)
{
if (v[low] <= v[pivot_index])
{
low++;
}
else if (v[high] > v[pivot_index])
{
high--;
}
else
{
Swap(v, low, high);
}
}
// Put pivot back between two groups.
if (high != pivot_index)
{
Swap(v, pivot_index, high);
}
return high;
}
// Swap function.
static void Swap(int* v, unsigned a, unsigned b)
{
unsigned tmp;
tmp = v[a];
v[a] = v[b];
v[b] = tmp;
}
// Print function.
static void PrintArray(void)
{
int i;
printf("[");
for (i = 0; i < (ITEMS - 1); i++)
{
printf("%d, ", v[i]);
}
printf("%d]\n\n", v[ITEMS-1]);
printf("[");
for (i = 0; i < (ITEMS - 1); i++)
{
printf("%d, ", sorted[i]);
}
printf("%d]\n\n", sorted[ITEMS - 1]);
}