Rename low-rank Choleksy factor (LRCF) to low-rank (LR)

[ullmannsven]

Renaming LRCF to LR across all relevant places within pymor. The alternative would be to rename LRADI to LRCFADI, which is currently not the preferred option.

dummy PR in order to have it open before the soft freeze. I will work on this as soon as #2572 is merged.

[codecov]

Codecov Report

❌ Patch coverage is 91.25000% with 14 lines in your changes missing coverage. Please review.
✅ Project coverage is 88.08%. Comparing base (67665e6) to head (1a4be65).

Files with missing lines	Patch %	Lines
src/pymor/solvers/matrix_equations/default.py	61.53%	10 Missing ⚠️
src/pymor/models/iosys.py	93.02%	3 Missing ⚠️
src/pymor/solvers/matrix_equations/lradi.py	75.00%	1 Missing ⚠️

Additional details and impacted files

Flag	Coverage Δ
github_actions	78.31% <91.25%> (-0.01%)	⬇️
gitlab_ci	88.00% <91.25%> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
src/pymor/bindings/scipy.py	89.41% <100.00%> (ø)
src/pymor/bindings/slycot.py	96.46% <100.00%> (ø)
src/pymor/reductors/bt.py	86.84% <100.00%> (ø)
src/pymor/reductors/sobt.py	83.42% <100.00%> (ø)
src/pymor/solvers/matrix_equations/equations.py	94.32% <100.00%> (ø)
src/pymor/solvers/matrix_equations/interface.py	86.27% <100.00%> (ø)
src/pymor/solvers/matrix_equations/lrradi.py	86.74% <100.00%> (-0.16%)	⬇️
src/pymordemos/heat.py	97.16% <100.00%> (ø)
src/pymordemos/parametric_delay.py	96.00% <ø> (ø)
src/pymordemos/parametric_heat.py	99.50% <ø> (ø)
... and 10 more

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[pmli]

Please also change appearances of "low-rank Cholesky factor" to "low-rank factor".

[ullmannsven]

Please also change appearances of "low-rank Cholesky factor" to "low-rank factor".

okay, I thought to leave this as it is in order to have additional descriptive value, but tbh i dont have an opinion on this and if its clear anyway that this is a Choleksy factor then i will remove it. Thanks for taking a look so fast!

[pmli]

Please also change appearances of "low-rank Cholesky factor" to "low-rank factor".

okay, I thought to leave this as it is in order to have additional descriptive value, but tbh i dont have an opinion on this and if its clear anyway that this is a Choleksy factor then i will remove it. Thanks for taking a look so fast!

Well, that's the whole issue with "LRCF" to begin with, because $Z Z^T$ is not a Cholesky factorization unless $Z$ is a square lower-triangular matrix.