Minor fixes to FTSP

[pehamTom]

Description

Fixed edgede case in heuristic state prep for codes with even distances. Furthermore changed calculation of logical error rate to be calculated per qubit

Checklist:

• [x] The pull request only contains commits that are related to it.
• [x] I have added appropriate tests and documentation.
• [x] I have made sure that all CI jobs on GitHub pass.
• [x] The pull request introduces no new warnings and follows the project's style guidelines.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 82.7%. Comparing base (bc00666) to head (6ac26e6).

Additional details and impacted files

[](https://app.codecov.io/gh/cda-tum/mqt-qecc/pull/243?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cda-tum) ```diff @@ Coverage Diff @@ ## main #243 +/- ## ===================================== Coverage 82.7% 82.7% ===================================== Files 29 29 Lines 3170 3170 Branches 190 190 ===================================== Hits 2623 2623 Misses 547 547 ``` | [Flag](https://app.codecov.io/gh/cda-tum/mqt-qecc/pull/243/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cda-tum) | Coverage Δ | | *Carryforward flag | |---|---|---|---| | [cpp](https://app.codecov.io/gh/cda-tum/mqt-qecc/pull/243/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cda-tum) | `80.2% <ø> (ø)` | | Carriedforward from [40d3427](https://app.codecov.io/gh/cda-tum/mqt-qecc/commit/40d342751ff636ea484d487e06be60e7ecd4ddd0?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cda-tum) | | [python](https://app.codecov.io/gh/cda-tum/mqt-qecc/pull/243/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cda-tum) | `83.7% <100.0%> (ø)` | | | *This pull request uses carry forward flags. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cda-tum) to find out more. | [Files](https://app.codecov.io/gh/cda-tum/mqt-qecc/pull/243?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cda-tum) | Coverage Δ | | |---|---|---| | [src/mqt/qecc/ft\_stateprep/simulation.py](https://app.codecov.io/gh/cda-tum/mqt-qecc/pull/243?src=pr&el=tree&filepath=src%2Fmqt%2Fqecc%2Fft_stateprep%2Fsimulation.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cda-tum#diff-c3JjL21xdC9xZWNjL2Z0X3N0YXRlcHJlcC9zaW11bGF0aW9uLnB5) | `85.5% <100.0%> (ø)` | | | [src/mqt/qecc/ft\_stateprep/state\_prep.py](https://app.codecov.io/gh/cda-tum/mqt-qecc/pull/243?src=pr&el=tree&filepath=src%2Fmqt%2Fqecc%2Fft_stateprep%2Fstate_prep.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cda-tum#diff-c3JjL21xdC9xZWNjL2Z0X3N0YXRlcHJlcC9zdGF0ZV9wcmVwLnB5) | `75.7% <100.0%> (ø)` | |