[ITensors] [BUG] svdMPO generates unnecessarily large intermediate weight matrices

[b-kloss]

Description

Replaces Vector filled with references to the same Dict with a Vector of references to independent Dicts. This reduces the dimensions of intermediate weight matrices, on which compression via SVD is performed.

How Has This Been Tested?

Passes tests in test/ITensorLegacyMPS/base. (One broken, not sure why?)

Checklist:

• My code follows the style guidelines of this project. Please run using JuliaFormatter; format(".") in the base directory of the repository (~/.julia/dev/ITensors) to format your code according to our style guidelines.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have added tests that verify the behavior of the changes I made.
• I have made corresponding changes to the documentation.
• [] My changes generate no new warnings.
• Any dependent changes have been merged and published in downstream modules.

[codecov-commenter]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Comparison is base (fe84b9e) 85.31% compared to head (97b889d) 53.84%.
Report is 7 commits behind head on main.

❗ Current head 97b889d differs from pull request most recent head ecbbcae. Consider uploading reports for the commit ecbbcae to get more accurate results

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Additional details and impacted files

@@             Coverage Diff             @@
##             main    #1231       +/-   ##
===========================================
- Coverage   85.31%   53.84%   -31.47%     
===========================================
  Files          89       87        -2     
  Lines        8445     7898      -547     
===========================================
- Hits         7205     4253     -2952     
- Misses       1240     3645     +2405     

Files	Coverage Δ
src/physics/autompo/opsum_to_mpo.jl	0.00% <0.00%> (-100.00%)	⬇️

... and 65 files with indirect coverage changes

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[mtfishman]

[test ITensors mps]

[github-actions]

Run ITensors mps tests from comment trigger: succeeded ✅
https://github.com/ITensor/ITensors.jl/actions/runs/6739622318

[github-actions]

Run ITensors mps tests from comment trigger: succeeded ✅
https://github.com/ITensor/ITensors.jl/actions/runs/6739622318

[mtfishman]

Thanks! Tests marked as broken are just things that we now are broken and would like to fix in the future, you can ignore that.

[emstoudenmire]

Thanks Benedikt!