Deprecating np.bool Type Alias

[zachcoleman]

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Motivation

Gets rid of instances of np.bool to increase compatibility with newer versions of numpy. For more details see: https://numpy.org/doc/stable/release/1.20.0-notes.html#deprecations.

Note: np.bool has just been an alias for bool

Modification

Replaces all np.bool instances w/ bool.

BC-breaking (Optional)

Not applicable

Use cases (Optional)

Not applicable

Checklist

1. Pre-commit or other linting tools are used to fix the potential lint issues.
2. The modification is covered by complete unit tests. If not, please add more unit test to ensure the correctness.
3. If the modification has potential influence on downstream projects, this PR should be tested with downstream projects, like MMDet or MMCls.
4. The documentation has been modified accordingly, like docstring or example tutorials.

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[hhaAndroid]

@zachcoleman Hi, I would like to ask if there is a problem if the user version is lower than 1.20?

[zachcoleman]

Details

@hhaAndroid There should be no problem. np.bool is just an alias and another variable pointing to bool. As an example here's numpy v1.19.5:

and another version v1.16.6 (this version is ~3 years old):

I believe using bool is the most compatible way to define these arrays across versions. There is work for 1.25.0 (scheduled for June 2023) to add np.bool back into numpy.

I will follow up when I get an answer here to try and determine the best course forward. My instinct is that bool is probably the best way to do this for <1.20, 1.20-1.24, and 1.25+ based on the logic to map bool accordingly (see here).

[openmmlab-bot]

Dear zachcoleman,
First of all, we want to express our gratitude for your significant PR in the MMDet project. Your contribution is highly appreciated, and we are grateful for your efforts in helping improve this open-source project during your personal time. We believe that many developers will benefit from your PR.
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