Best program is not saved after reducing population

[maisyhoang]

I reduced the population from 100 to 20, with the hope the evolution get faster. However, it seems to mess up the best solution book keeping as the new best solution (iteration 126, combined_score=-0.9347) can't be saved due to it "no longer exists". After that, the best solution is wrong and worse solutions deemed as the best one. After iteration 128, combined_score=-2.08 is deemed best solutions, yet in the checkpoint later we see that there are better solutions.

I attached the full log below the screenshot.

openevolve_20250712_015411.log

[codelion]

Is this with the latest version? I believe it should been fixed in #136

Can you share the full output folder and I can take a look if it is still happening.

[maisyhoang]

It is not the latest version. I will update and try again from checkpoint 125 too see if that behavior still exist and report back.

[maisyhoang]

I try setting my evaluator to return a better score the next time it got run. So far I have not been able to reproduce the issue.

Btw, I see a minor bug with https://github.com/codelion/openevolve/blob/68665a53cc933aece6680da5d38d41d993e97d67/openevolve/database.py#L1164 This logger debug line is never prints (despite I already set the logger level to Debug). Weirdly, some of the logger debug is printed when the program first initialized. I put a info print one line before it at "INFO INFO: Removed program", which does get printed: openevolve_20250712_160305.log. I suspects that not all the logger.debug() is working. My openevolve submodule is now at the latest commit in master (68665a5).

I think we could close this issue, if you think the new minor bug better be in its own separate issue.

Update:
I think I found the logger issue, it is always assigned back to the default value of INFO if not specified by the command line. I am not sure if this is expected behavior. I configured logging level using the yaml file. Also, there are some calls to logging.info() and logging.debug() that should be logger.info() and logger.debug().
https://github.com/codelion/openevolve/blob/68665a53cc933aece6680da5d38d41d993e97d67/openevolve/cli.py#L122

I open this pull request to fix the logger issue #142