Add truncerr truncation strategy

[mtfishman]

This adds a new MatrixAlgebraKit.jl truncation strategy to minimize the rank without the error in the factorization going above a certain threshold.

Related to https://github.com/Jutho/TensorKit.jl/blob/v0.14.5/src/tensors/truncation.jl and https://github.com/ITensor/ITensors.jl/blob/v0.9.2/NDTensors/src/lib/RankFactorization/src/truncate_spectrum.jl.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.41%. Comparing base (d4f0c86) to head (19d8d6b).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##            main      #59       +/-   ##
==========================================
+ Coverage   0.00%   94.41%   +94.41%     
==========================================
  Files         12       14        +2     
  Lines        386      412       +26     
==========================================
+ Hits           0      389      +389     
+ Misses       386       23      -363     

Flag	Coverage Δ
docs	0.00% <0.00%> (ø)

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[mtfishman]

@lkdvos it is pretty simple but I'm curious to hear your thoughts on the design.

I figure something like this could go in MatrixAlgebraKit.jl but we could try it out here first.

[lkdvos]

Definitely looks good to me. Any idea why codecov seems to be indicating that findtruncated is not covered? Just looking at the tests, that shouldn't be the case right?

[mtfishman]

Definitely looks good to me. Any idea why codecov seems to be indicating that findtruncated is not covered? Just looking at the tests, that shouldn't be the case right?

Hmm good question, I've basically just started ignoring the codecov comments since it seems random to me. If you check the coverage on the codecov website (https://app.codecov.io/gh/ITensor/TensorAlgebra.jl/pull/59) it says they are covered so maybe the comments are outdated. I think maybe what happens is that the codecov comments get posted before the tests finish running so they give false negatives, maybe there is a way to fix that...