Haoti/arnoldi ut

[hunghaoti]

Add function Arnoldi support for Dense UniTensor.

[kaihsin]

I would suggest for any internal functions that you don't want to expose, using underscore and lowercase with underscore separators for naming it, instead of Capitalize separator. for example:

GetEig -> _get_eigenval

Other than that LGTM

[hunghaoti]

I would suggest for any internal functions that you don't want to expose, using underscore and lowercase with underscore separators for naming it, instead of Capitalize separator. for example:

GetEig -> _get_eigenval

Other than that LGTM

OK, I will modify it.

[codecov]

Codecov Report

Attention: Patch coverage is 17.66667% with 247 lines in your changes are missing coverage. Please review.

Project coverage is 16.58%. Comparing base (e518b8b) to head (efc880f).

Files	Patch %	Lines
src/linalg/Lanczos_Exp.cpp	7.32%	107 Missing and 70 partials ⚠️
src/linalg/Arnoldi.cpp	35.77%	1 Missing and 69 partials ⚠️

Additional details and impacted files

@@              Coverage Diff               @@
##           dev-master     #413      +/-   ##
==============================================
+ Coverage       16.49%   16.58%   +0.09%     
==============================================
  Files             220      221       +1     
  Lines           48275    48388     +113     
  Branches        20126    20241     +115     
==============================================
+ Hits             7961     8027      +66     
+ Misses          36183    36091      -92     
- Partials         4131     4270     +139     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.