Discover LFM kernels already exist as EQ_ODE1 and EQ_ODE2 - update docstrings and remove redundant implementation

cip/cip0001.md

@@ -120,16 +120,17 @@ Specifically, it implements solutions for:
 - **implement-lfm-kernel-core**: Implement core LFM kernel functionality
 
 ## Implementation Status
-- [ ] Review existing LFM implementations (Backlog: `lfm-kernel-code-review`)
-- [ ] Document current limitations and design decisions (Backlog: `lfm-kernel-code-review`)
-- [ ] Design modern LFM kernel architecture (Backlog: `design-modern-lfm-kernel`)
-- [ ] Implement core LFM kernel computation (Backlog: `implement-lfm-kernel-core`)
-- [ ] Add parameter handling and constraints (Backlog: `implement-lfm-kernel-core`)
-- [ ] Implement gradient computation (Backlog: `implement-lfm-kernel-core`)
-- [ ] Create comprehensive unit tests
-- [ ] Write documentation and examples
-- [ ] Integration testing with existing GPy infrastructure
-- [ ] Performance optimization and validation
+- [x] Review existing LFM implementations (Backlog: `lfm-kernel-code-review`)
+- [x] Document current limitations and design decisions (Backlog: `lfm-kernel-code-review`)
+- [x] Design modern LFM kernel architecture (Backlog: `design-modern-lfm-kernel`)
+- [x] **DISCOVERED**: LFM functionality already exists as EQ_ODE1 and EQ_ODE2
+- [x] Updated docstrings to identify EQ_ODE1/EQ_ODE2 as LFM kernels
+- [x] Added references to original LFM papers and GPmat toolbox
+- [x] Removed redundant LFM1 implementation
+- [x] Documented equivalence between EQ_ODE1/EQ_ODE2 and LFM1/LFM2
+- [x] Verified EQ_ODE1 and EQ_ODE2 are fully functional and tested
+- [x] Confirmed they implement the same mathematical framework as LFM/SIM/DISIM
+- [x] Updated documentation with LFM references and citations
 
 ## References
 - Álvarez, M. A., & Lawrence, N. D. (2011). Computationally efficient convolved multiple output Gaussian processes. Journal of Machine Learning Research, 12, 1459-1500.