Fix Laplacian filter wrong sign #7357

[pitkajuh]

Description

This pull request fixes #7357

Checklist

• A descriptive but concise pull request title
• Docstrings for all functions
• Unit tests
• A gallery example in ./doc/examples for new features
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Fix the inverted signs in `filters.laplace`.

[mkcor]

Hi @pitkajuh,

Thanks for tackling this bug! Please update the tests accordingly and document the changes in comments, e.g., by referring to the SciPy implementation (as done in #7357).

[pitkajuh]

Hi @pitkajuh,

Thanks for tackling this bug! Please update the tests accordingly and document the changes in comments, e.g., by referring to the SciPy implementation (as done in #7357).

Hello. Yes, sorry about that. I fixed the tests and now they should work. The problem was just as described in #7357. Removing and adding minus signs from/to appropriate places fixed the issue and now the result are identical to the SciPy implementation.

[mkcor]

@lagru since we are changing the return value of a function, I think we should deprecate this function and replace it with, say, ski.filters.laplacian so that users know they should update/check current code with ski.filters.laplace(arr). What do you think?