🚀 Overview

This release introduces a comprehensive advanced linear solver for robot parameter identification, along with significant module reorganization for improved code maintainability and extensibility.

✨ Major Features

1. Advanced Linear Solver (figaroh.tools.solver)

• 10 Solving Methods:
  • Basic: lstsq, qr, svd
  • Regularized: ridge, lasso, elastic_net, tikhonov
  • Advanced: constrained, robust, weighted
• Regularization:
  • L1 (Lasso) for sparse solutions
  • L2 (Ridge) for stability
  • Elastic Net combining L1 & L2
  • Custom Tikhonov with user-defined matrices
• Constraint Support:
  • Box constraints (bounds on each variable)
  • Linear equality constraints (A_eq @ x = b_eq)
  • Linear inequality constraints (A_ineq @ x <= b_ineq)
• Quality Metrics:
  • RMSE, R², condition number
  • Residual norms and singular values
• Optimized for dense, large, thin matrices typical in robot dynamics

2. Module Reorganization

Calibration Module:

• config.py (624 lines): Configuration parsing & YAML handling
• parameter.py (240 lines): Parameter management utilities
• data_loader.py (160 lines): Data loading & I/O operations

Identification Module:

• config.py (334 lines): Configuration parsing
• parameter.py (388 lines): Parameter management

Code Reduction:

• calibration_tools.py: -58% (1,500 → 630 lines)
• identification_tools.py: -67% (900 → 295 lines)

3. BaseIdentification Enhancement

• New solve_with_custom_solver() method
• Flexible solving with regularization and constraints
• Support for physical parameter bounds (e.g., positive masses/inertias)

🔧 Improvements

Parameter Ordering

Changed to Pinocchio dynamic parameter ordering:

• New: [Ixx, Ixy, Ixz, Iyy, Iyz, Izz, mx, my, mz, m]
• Previous: [m, mx, my, mz, Ixx, Ixy, Iyy, Ixz, Iyz, Izz]

Regressor Module

• Cleaned up build_basic_regressor methods
• Removed unused tau parameter
• Improved method signatures and documentation

Code Quality

• Significant reduction in code duplication
• Modular design with single responsibilities
• 100% backward compatibility maintained through re-exports

🧪 Testing

• 18 comprehensive unit tests in tests/unit/test_solver.py
• All tests passing in development environment
• Coverage includes:
  • All 10 solver methods
  • Edge cases and error handling
  • Robot identification scenarios
  • Regularization and constraints

🐛 Bug Fixes

• Parameter naming: Changed from numbered indices to parent joint names
• Regressor handling: Better support for additional columns
• Results manager imports and formatting issues

📝 Files Changed

• Modified: 6 files
• New: 7 files
• Total: 13 files

🔄 Migration Notes

• Backward Compatible: All existing code continues to work
• New Features: Optional - can be adopted gradually
• Parameter Order: Only affects internal computations, APIs unchanged

🔗 Related

• Resolves branch divergence (devel 38 commits ahead of main)
• Preserves all version history from both branches
• Clean integration via professional release branch workflow

✅ Checklist

• All tests passing (18/18)
• CHANGELOG.md updated
• Module reorganization complete
• Backward compatibility maintained
• Documentation inline with code
• No breaking API changes