Optimize the GPU code of gint_rho using the CUDA math library

[dzzz2001]

Details

The current gint_rho algorithm uses atomicAdd at the bottom level, which is inefficient. Can we use CUDA math library functions to replace atomicAdd and speed up the gint_rho program?

Task list for Issue attackers (only for developers)

• [ ] Reproduce the performance issue on a similar system or environment.
• [ ] Identify the specific section of the code causing the performance issue.
• [ ] 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.

[mohanchen]

Thanks! We suggest the issues be raised in another repository, https://github.com/deepmodeling/abacus-develop/issues