Improve operator's performance

[denghuilu]

Details

Reduce redundant computing of variables like 'ib * max_npw + ig '

Task list for Issue attackers (only for developers)

• [X] Reproduce the performance issue on a similar system or environment.
• [X] Identify the specific section of the code causing the performance issue.
• [X] Investigate the issue and determine the root cause.
• [ ] Research best practices and potential solutions for the identified performance issue.
• [ ] Implement the chosen solution to address the performance issue.
• [ ] Test the implemented solution to ensure it improves performance without introducing new issues.
• [ ] Optimize the solution if necessary, considering trade-offs between performance and other factors (e.g., code complexity, readability, maintainability).
• [ ] Review and incorporate any relevant feedback from users or developers.
• [ ] Merge the improved solution into the main codebase and notify the issue reporter.