Creating Parallel Regions

• Only one way to create threads in OpenMP API:
• Fortran:
• C/C++:
• Replicate execution:

C$OMP PARALLEL [clause[,clause]…]

code to run in parallel

C$OMP END PARALLEL

#pragma omp parallel [clause[,clause]…]

{

code to run in parallel

}

I=0

C$OMP PARALLEL

call foo(I, a, b, c)

C$OMP END PARALLEL

print*, I

Number of threads specified by user:

library: call omp_set_num_threads(128)

Environment: setenv OMP_NUM_THREADS 128

Block of code:

It is illegal to jump in

or out of that block

Data association rules(shared,private, etc.) have to be specified at start of parallel region (default shared)

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