2025-08-15 08:24:01 +02:00
|
|
|
---
|
|
|
|
|
id: "implement-lfm-kernel-core"
|
|
|
|
|
title: "Implement core LFM kernel functionality"
|
2025-08-15 11:50:10 +02:00
|
|
|
status: "In Progress"
|
2025-08-15 08:24:01 +02:00
|
|
|
priority: "High"
|
|
|
|
|
created: "2025-08-15"
|
|
|
|
|
last_updated: "2025-08-15"
|
|
|
|
|
owner: "Neil Lawrence"
|
2025-08-15 08:27:09 +02:00
|
|
|
github_issue: ""
|
|
|
|
|
dependencies: "design-modern-lfm-kernel"
|
2025-08-15 08:24:01 +02:00
|
|
|
tags:
|
|
|
|
|
- lfm
|
|
|
|
|
- kernel
|
|
|
|
|
- implementation
|
|
|
|
|
- core
|
|
|
|
|
---
|
|
|
|
|
|
|
|
|
|
# Implement core LFM kernel functionality
|
|
|
|
|
|
|
|
|
|
## Description
|
|
|
|
|
Implement the core LFM kernel class with basic functionality including kernel computation, parameter handling, and gradient computation.
|
|
|
|
|
|
|
|
|
|
## Background
|
|
|
|
|
- Design phase completed with modern LFM kernel architecture
|
|
|
|
|
- Need to implement the core kernel computation methods
|
|
|
|
|
- Should follow the mathematical foundations from the papers and MATLAB implementation
|
|
|
|
|
|
|
|
|
|
## Implementation Tasks
|
2025-08-15 11:50:10 +02:00
|
|
|
- [x] Create test specification for `GPy.kern.LFM1` and `GPy.kern.LFM2` classes (test-driven design)
|
|
|
|
|
- [ ] Create `GPy.kern.LFM1` class inheriting from appropriate base class
|
|
|
|
|
- [ ] Create `GPy.kern.LFM2` class inheriting from appropriate base class
|
2025-08-15 08:24:01 +02:00
|
|
|
- [ ] Implement parameter handling for mass, damper, spring, sensitivity, delay
|
|
|
|
|
- [ ] Implement `K()` method for kernel matrix computation
|
|
|
|
|
- [ ] Implement `Kdiag()` method for diagonal computation
|
|
|
|
|
- [ ] Add parameter constraints and transformations
|
|
|
|
|
- [ ] Implement basic gradient computation
|
|
|
|
|
- [ ] Add support for different base kernels for latent functions
|
|
|
|
|
|
|
|
|
|
## Core Methods to Implement
|
2025-08-15 11:50:10 +02:00
|
|
|
- [ ] `__init__()` - Parameter initialization and validation (LFM1 and LFM2)
|
|
|
|
|
- [ ] `K(X, X2=None)` - Kernel matrix computation (LFM1 and LFM2)
|
|
|
|
|
- [ ] `Kdiag(X)` - Diagonal computation (LFM1 and LFM2)
|
|
|
|
|
- [ ] `update_gradients_full()` - Gradient computation (LFM1 and LFM2)
|
|
|
|
|
- [ ] `update_gradients_diag()` - Diagonal gradient computation (LFM1 and LFM2)
|
|
|
|
|
- [ ] `parameters_changed()` - Parameter update handling (LFM1 and LFM2)
|
2025-08-15 08:24:01 +02:00
|
|
|
|
|
|
|
|
## Acceptance Criteria
|
|
|
|
|
- [ ] Core LFM kernel class implemented and functional
|
|
|
|
|
- [ ] Basic kernel computation working correctly
|
|
|
|
|
- [ ] Parameter handling and constraints implemented
|
|
|
|
|
- [ ] Gradient computation implemented
|
|
|
|
|
- [ ] Unit tests passing for core functionality
|
|
|
|
|
- [ ] Integration with GPy's parameterization system
|
|
|
|
|
|
|
|
|
|
## Implementation Notes
|
|
|
|
|
- Follow the mathematical structure from the MATLAB implementation
|
|
|
|
|
- Use GPy's parameterization system for constraints
|
|
|
|
|
- Implement efficient computation methods
|
|
|
|
|
- Ensure proper handling of edge cases and numerical stability
|
|
|
|
|
- Add comprehensive docstrings and documentation
|
|
|
|
|
|
|
|
|
|
## Related
|
|
|
|
|
- CIP: 0001 (LFM kernel implementation)
|
|
|
|
|
- Backlog: design-modern-lfm-kernel
|
|
|
|
|
- Papers: Álvarez et al. (2009, 2012)
|
2025-08-15 11:50:10 +02:00
|
|
|
|
|
|
|
|
## Progress Updates
|
|
|
|
|
|
|
|
|
|
### 2025-08-15
|
|
|
|
|
Implementation task started after completion of test-driven design:
|
|
|
|
|
- Design phase completed with comprehensive test suite
|
|
|
|
|
- Test specification defines expected API and behavior
|
|
|
|
|
- Ready to implement LFM1 and LFM2 kernel classes
|
|
|
|
|
- Test framework validated and working correctly
|
