Structural interpretability in SVMs with truncated orthogonal polynomial kernels
Summary
A new diagnostic framework, Orthogonal Representation Contribution Analysis (ORCA), has been developed for post-training interpretability of Support Vector Machines (SVMs) that utilize truncated orthogonal polynomial kernels. This method leverages the finite-dimensional nature of the associated reproducing kernel Hilbert space (RKHS) and its explicit tensor-product orthonormal basis to expand the fitted decision function in intrinsic RKHS coordinates. ORCA introduces normalized Orthogonal Kernel Contribution (OKC) indices, which quantify the distribution of the classifier's squared RKHS norm across various structural aspects, including interaction orders, total polynomial degrees, marginal coordinate effects, and pairwise contributions. The methodology is entirely post-training, eliminating the need for surrogate models or retraining, and has been demonstrated on a synthetic double-spiral problem and a real five-dimensional echocardiogram dataset, revealing model complexity aspects beyond predictive accuracy.
Key takeaway
For Machine Learning Engineers building or evaluating Support Vector Machines with polynomial kernels, ORCA offers a novel way to understand model complexity and feature contributions. You should consider applying ORCA to gain structural insights into your SVMs, especially when predictive accuracy alone does not fully explain model behavior, helping to diagnose and refine your models more effectively.
Key insights
ORCA provides structural interpretability for SVMs using truncated orthogonal polynomial kernels via OKC indices.
Principles
- RKHS finite-dimensionality enables exact decision function expansion.
- Model complexity extends beyond predictive accuracy.
Method
ORCA uses normalized Orthogonal Kernel Contribution (OKC) indices to quantify how an SVM's squared RKHS norm distributes across interaction orders, polynomial degrees, and marginal/pairwise effects, all post-training.
In practice
- Analyze SVM complexity without retraining.
- Identify key feature interactions in SVMs.
Topics
- Support Vector Machines
- Model Interpretability
- Orthogonal Polynomial Kernels
- RKHS Coordinates
- ORCA Framework
Best for: AI Scientist, Machine Learning Engineer, Research Scientist
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Editorial summary, takeaway, and curation by AIssential. Original article published by Takara TLDR - Daily AI Papers.