Optimize eoRanking: Add caching and index vector

[Alessandro624]

This PR improves the performance of the eoRanking class by introducing two key enhancements:

• Cached Coefficients:

  • Precomputes and stores intermediate constants (e.g., alpha, beta, gamma).

  • These are recomputed only when the population size changes, improving runtime efficiency for repeated evaluations.

• Index Vector:

  • Replaces the costly lookfor loop with a std::vector for O(1) lookup of individual indices.

  • This avoids potential runtime errors and simplifies the ranking logic.

Fully preserves compatibility with the EO framework (eoPerf2Worth, eoPop).

[nojhan]

Thanks for the contribution! This is a neat feature, which we must include in Paradiseo.

However, adding a cache system rely on the idea that the instantiated operator is always used in the same context. In the case of automated design, this is not always the case. Thus, I think this class should either:

• be a new class, like eoRankingCached,
• have a configurable cache, with the cache disabled by default.

I would also like to have more comments, given that the system is not immediately obvious to the reader. Something like starting from the PR message and extend a bit, in the class' header, perhaps?

Finally, a simple test ensuring that both implementations produces the same result would be a convincing check that everything is perfectly working.

[Alessandro624]

Thank you for your review and suggestions. I've implemented the requested changes:

• Created a separate eoRankingCached class to maintain clear separation from the original implementation

• Added more comments including:

  • Detailed class header comments explaining the caching mechanism

  • Usage guidelines

  • Clear warning about constant population size requirement

• Implemented some tests that verifies:

  • Identical results between cached and original versions

  • Edge case handling (including minimum population size)

[nojhan]

Impressive work!

Apart from the very minor comments, I think it would be better if we had those two classes in two separate files. I know it's not always the case in all the old codebase, but I think that would really help discoverability, for users who look at files directly.

Also, the indentation seems to be inconsistent, with sometime two spaces, sometime four. I think four is more or less the standard in Paradiseo (even if we have mixed styles…).

[Alessandro624]

Thank you for your review and valuable feedback. I have implemented both of your requested changes:

• Separated the classes into individual files to improve code organization and discoverability

• Standardized the indentation to use 4 spaces consistently throughout

Additionally, the newly added test cases confirm that all assertions are functioning as intended.

[nojhan]

Almost perfect! I'm just nitpicking about asserts, but once fixed, I will merge. I tested locally, and everything merges well and passes tests.

[nojhan]

Also, don't forget to "resolve conversations" that are fixed in further commits.

[nojhan]

Just a last inconsistency.

[nojhan]

Awesome! Thanks for the contribution!

[Alessandro624]

Thanks for the detailed feedback and suggestions!

[nojhan]

No problem. I'm looking forward for the next contribution ;-) And I hope you find Paradiseo useful.