1.Explain clearly whether the following program using OpenMP directives will
compile correctly. Correct the program if it does not compile correctly. What
are the possible outputs from this program? Explain your answer clearly.
#include
#include
int main() {
int section_count = 0;
#pragma omp parallel
#pragma omp sections firstprivate(section_count)
{
#pragma omp section
{
section_count++;
printf( “section_count= %d\n”, section_count );
}
#pragma omp section
{
section_count++;
printf( “section_count= %d\n”, section_count );
}
}
return 0;
}
2.(a)Consider the following code. What are the entries of the array A after the pro-
gram terminates? Parallelize the for loop using OpenMP directives. Explain
why this OpenMP code will be inefficient.
#include
#include
int main()
{
int i,j, A[5];
j=4;
for(i=0;i<5;i++)
{
j=j*2;
A[i]=j;
}
}
3.Change the program in part (a) so that the parallelization of the for loop
using OpenMP is more efficient. You can assume any extra function you like,
but you need to explain it clearly.
Explain clearly whether the following program using OpenMP directives will
compile correctly. Write a corrected version of the program if the program
does not compile correctly. What does the program do?
#include
#include
#include
#define N 50
#define CHUNKSIZE 5
int main (int argc, char *argv[])
{
int i, chunk, tid;
float a[N], b[N], c[N];
for (i=0; i < N; i++)
a[i] = b[i] = i * 1.0;
chunk = CHUNKSIZE;
#pragma omp parallel for \
shared(a,b,c,chunk) \
private(i,tid) \
schedule(static,chunk)
{
tid = omp_get_thread_num();
for (i=0; i < N; i++)
{
c[i] = a[i] + b[i];
printf("tid= %d i= %d c[i]= %f\n", tid, i, c[i]);
}
}
}
4. #include
#include
#include
int main(void){
int i;
int x;
x=44;
#pragma omp parallel for lastprivate(x)
for(i=0;i<=10;i++){
x=i;
printf("Thread number: %d x: %d\n",omp_get_thread_num(),x);
}
printf("x is %d\n", x);
}
A partial output from this program is given below. Complete the remaining
part of the output and explain your answer.
Thread number: 7 x: 10
Thread number: 3 x: 6
Thread number: 2 x: 4
Thread number: 2 x: 5