BEAST extension

[JoshuaTetzner]

I wrote an extensions allowing to use HMatrices for the boundary element toolkit BEAST.jl.
The extension adds BEAST.jl as a weak dependency which means that BEAST.jl is not required as a package but an optional add on. Only if BEAST.jl is loaded before HMatrices the extension will be available.
I would be pleased if this extension is accepted an merged to this package.
In addition I have wrote an AdaptiveCrossApproximation package still under development, providing different pivoting strategies as well as convergence criteria that can handle the problematic matrices appearing for integral equations such as block-structured ones.
I plan to finish and register the package in the next weeks an will provide an extension to HMatrices.jl.

[maltezfaria]

Thanks for the PR. Quick question: why not have an HMatrix extension on BEAST instead? This is what I did for another package of mine here. This direction of dependency seems more natural to me, so I was wondering if you have a reason for preferring to have the extension here.

[maltezfaria]

And I look forward to your AdapativeCrossApproximation package: would be cool to support other compression methods!

[codecov]

Codecov Report

❌ Patch coverage is 90.62500% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 76.73%. Comparing base (54ba356) to head (de7a2e2).

Files with missing lines	Patch %	Lines
ext/HBEAST/abstractmatrix.jl	90.62%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #84      +/-   ##
==========================================
+ Coverage   76.43%   76.73%   +0.30%     
==========================================
  Files          14       15       +1     
  Lines        1477     1509      +32     
==========================================
+ Hits         1129     1158      +29     
- Misses        348      351       +3     

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[JoshuaTetzner]

Thanks for the response, I see your point. To follow your style I will move this extension either to BEAST.jl or then to the AdaptiveCrossApproximation package.
Personally I see the extension better located in the subordinate package which would be in the fast method package.

[maltezfaria]

I see.... I don't have an issue having it merged here, just that it would be more natural the other way around. Feel free to re-open the PR if you for some reason you can't get it merged to BEAST.

[JoshuaTetzner]

Thank you very much for the offer I will discuss it with the owner of BEAST and might reopen the pull request if I do not find another pleasing solution.