Fix for issue #620

[apanichella]

This PR fixes the error in issue #620

The previous implementation can lead to division by zero or extremely large exponential values that can lead to overflow problems for constrained problems.

This PR fixes these errors as follows:

• Regularization with epsilon: The small constant epsilon is added to each value of point[obj_index] before raising it to the power of x. This prevents the base of the exponentiation from becoming too small, which can lead to extremely large results when x is large.
• Logarithm Handling: The logarithm calculation is adjusted to prevent taking the log of non-positive numbers.
• Zero Handling: If the denominator (denominator) or the derivative (ff) is zero, the function returns a fallback value to avoid division by zero.

[muazhari]

You are missing another error in this PR.

[apanichella]

For which problem do you get this error? That would help me debugging the code

[muazhari]

For which problem do you get this error? That would help me debugging the code

This: https://gist.github.com/muazhari/deed94f293489e95a75e95c057f5e98f

[apanichella]

On my machine, I don't get that error. I have also tried with different seeds

[muazhari]

Another error again in this: https://gist.github.com/muazhari/0825646b3767402b1899881836b36c42

I don't know if mixed variable modification to the GA algorithm is interoperable with agemoea2. I think it should because it uses the same abstraction in the superset class (GA), and is not specific to agemoea2.

[muazhari]

On my machine, I don't get that error. I have also tried with different seeds

damn, how? My machine is currently a bit random as in my last GitHub issues to Pymoo, wsl, and Ray. Is it because intel stability issue? haha.

[muazhari]

On my machine, I don't get that error. I have also tried with different seeds

I tried to run 3 times and still got the same error. Can you try to execute in different log levels? Or make sure the stdout/stderr not obstructed?

[apanichella]

Another error again in this: https://gist.github.com/muazhari/0825646b3767402b1899881836b36c42

I don't know if mixed variable modification to the GA algorithm is interoperable with agemoea2. I think it should because it uses the same abstraction in the superset class (GA), and is not specific to agemoea2.

I also don't get this error on my machine (M3 Mac). But the last commit should consider/handle division with NaN and Inf value. This should prevent the error you have.

Actually, I am looking at the stack trace you have. It seems you are not using the code after my commits as the line f += np.power(point[obj_index], x) in your stack trace is now f += np.power(point[obj_index] + epsilon, x), which is the latest code.

[muazhari]

Actually, I am looking at the stack trace you have. It seems you are not using the code after my commits as the line f += np.power(point[obj_index], x) in your stack trace is now f += np.power(point[obj_index] + epsilon, x), which is the latest code.

My bad. After ensuring to use your latest commit, both gists above did not display any errors.

[muazhari]

For which problem do you get this error? That would help me debugging the code

This: https://gist.github.com/muazhari/deed94f293489e95a75e95c057f5e98f

Sorry, this first gist still has an error (the second gist is fixed). I don't know why the stack trace can't be displayed to the stdout when using logger/try-catch. After I removed it, the stack trace displayed the error. Please rerun the modified gist.

[apanichella]

For which problem do you get this error? That would help me debugging the code

This: https://gist.github.com/muazhari/deed94f293489e95a75e95c057f5e98f

Sorry, this first gist still has an error (the second gist is fixed). I don't know why the stack trace can't be displayed to the stdout when using logger/try-catch. After I removed it, the stack trace displayed the error. Please rerun the modified gist.

It should be fixed with the last commit

[muazhari]

In the second gist (https://gist.github.com/muazhari/0825646b3767402b1899881836b36c42), comes another warning: In the first gist (https://gist.github.com/muazhari/deed94f293489e95a75e95c057f5e98f), still has an earlier error.

[apanichella]

The last two commits should fix the issues in both gits. Let me know if you encounter more issues

[blankjul]

I have merged the code for now. Please open a new PR if another fix is needed.

[blankjul]

Thanks @apanichella for taking care of it!