Add comparison against known example for Hadamar product

[mgrub]

This PR fixes issue #331 and implements the trust anchor for the Hadamar product method.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 77.71%. Comparing base (b9debd7) to head (fe783f9).

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Additional details and impacted files

@@            Coverage Diff             @@
##             main     #332      +/-   ##
==========================================
- Coverage   77.83%   77.71%   -0.13%     
==========================================
  Files          30       30              
  Lines        2333     2333              
  Branches      378      378              
==========================================
- Hits         1816     1813       -3     
- Misses        390      392       +2     
- Partials      127      128       +1     

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