Ftsp

[pehamTom]

Description

This PR adds methods for synthesizing and simulating fault-tolerant state preparation circuits for CSS codes.

The main functionality introduced is:

• Optimal and heuristic synthesis of non-ft state preparation circuits
• Optimal and heuristic verification of a non-ft state preparation circuit
• Simulation methods to numerically estimate the logical error rate of a state-preparation circuit

Furthermore, this PR introduces a CSSCode class for convenience and adapts existing code implementations to conform to this class. For example, the HexagonalColorCode class now inherits from CSSCode. Some sample CSS codes are provided that can be directly imported via the CSSCode class.

Checklist:

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

[burgholzer]

You can ignore the macos-wheels job failure for now as it is broken at the moment.

[codecov]

Codecov Report

Attention: Patch coverage is 78.91098% with 244 lines in your changes missing coverage. Please review.

Project coverage is 82.7%. Comparing base (2ed6ce7) to head (40d3427).
Report is 122 commits behind head on main.

Files with missing lines	Patch %	Lines
src/mqt/qecc/ft_stateprep/state_prep.py	75.7%	187 Missing ⚠️
src/mqt/qecc/ft_stateprep/simulation.py	85.5%	35 Missing ⚠️
src/mqt/qecc/code.py	83.7%	22 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##            main    #234     +/-   ##
=======================================
- Coverage   85.0%   82.7%   -2.3%     
=======================================
  Files         25      29      +4     
  Lines       2024    3170   +1146     
  Branches     190     190             
=======================================
+ Hits        1721    2623    +902     
- Misses       303     547    +244     

Flag	Coverage Δ		*Carryforward flag
cpp	80.2% <ø> (ø)		Carriedforward from 2ed6ce7
python	83.7% <78.9%> (-5.2%)	⬇️

*This pull request uses carry forward flags. Click here to find out more.

Files with missing lines	Coverage Δ
src/mqt/qecc/__init__.py	100.0% <100.0%> (ø)
src/mqt/qecc/cc_decoder/color_code.py	91.4% <100.0%> (-1.3%)	⬇️
src/mqt/qecc/ft_stateprep/__init__.py	100.0% <100.0%> (ø)
src/mqt/qecc/code.py	83.7% <83.7%> (ø)
src/mqt/qecc/ft_stateprep/simulation.py	85.5% <85.5%> (ø)
src/mqt/qecc/ft_stateprep/state_prep.py	75.7% <75.7%> (ø)