allow to use SHT_REAL_NORM normalization

[nschaeff]

Expose in the julia interface the possibility to use "real normalization" :

cfg = SHTns.SHTnsCfg(13; norm = SHTns.Orthonormal(; real_norm=true))

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 45.70%. Comparing base (ce0285e) to head (70a03c6).

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #11      +/-   ##
==========================================
+ Coverage   45.58%   45.70%   +0.12%     
==========================================
  Files           9        9              
  Lines         430      431       +1     
==========================================
+ Hits          196      197       +1     
  Misses        234      234              

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[fgerick]

Can we add any tests to verify the normalizations are working as expected?

[nschaeff]

Do you have some test example I could adapt?

[fgerick]

Here I test the norms, it should give the same spatial field for all norms:
https://github.com/fgerick/SHTns.jl/blob/ce0285edd477585f3b790fa3332c3b00ce9a0ab2/test/runtests.jl#L55C1-L91C4