fix: add OpenMP parallel region for proper loop parallelization

Description of Change

Added an OpenMP parallel region for loops marked with #pragma omp for to enable actual parallel execution.

Previously, the loops had #pragma omp for without a surrounding parallel region, so they executed sequentially.
Now, loops in the function are wrapped in #pragma omp parallel for to correctly distribute iterations across threads.

References

Checklist

• [ x] Added description of change
• Added file name matchesFile name guidelines
• Added tests and example, test must pass
• Relevant documentation/comments is changed or added
• [ x] PR title follows semanticcommit guidelines
• [ x] Search previous suggestions before making a new one, as yours may be a duplicate.
• [ x] I acknowledge that all my contributions will be made under the project's license.

Notes: