Can Synthetic Data Improve Symbolic Regression Extrapolation Performance?

Fuente: arXiv
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Main Authors: Ramlan, Fitria Wulandari, O'Riordan, Colm, Kronberger, Gabriel, McDermott, James
Format: Preprint
Published: 2025
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author Ramlan, Fitria Wulandari
O'Riordan, Colm
Kronberger, Gabriel
McDermott, James
author_facet Ramlan, Fitria Wulandari
O'Riordan, Colm
Kronberger, Gabriel
McDermott, James
contents Many machine learning models perform well when making predictions within the training data range, but often struggle when required to extrapolate beyond it. Symbolic regression (SR) using genetic programming (GP) can generate flexible models but is prone to unreliable behaviour in extrapolation. This paper investigates whether adding synthetic data can help improve performance in such cases. We apply Kernel Density Estimation (KDE) to identify regions in the input space where the training data is sparse. Synthetic data is then generated in those regions using a knowledge distillation approach: a teacher model generates predictions on new input points, which are then used to train a student model. We evaluate this method across six benchmark datasets, using neural networks (NN), random forests (RF), and GP both as teacher models (to generate synthetic data) and as student models (trained on the augmented data). Results show that GP models can often improve when trained on synthetic data, especially in extrapolation areas. However, the improvement depends on the dataset and teacher model used. The most important improvements are observed when synthetic data from GPe is used to train GPp in extrapolation regions. Changes in interpolation areas show only slight changes. We also observe heterogeneous errors, where model performance varies across different regions of the input space. Overall, this approach offers a practical solution for better extrapolation. Note: An earlier version of this work appeared in the GECCO 2025 Workshop on Symbolic Regression. This arXiv version corrects several parts of the original submission.
format Preprint
id arxiv_https___arxiv_org_abs_2511_22794
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Can Synthetic Data Improve Symbolic Regression Extrapolation Performance?
Ramlan, Fitria Wulandari
O'Riordan, Colm
Kronberger, Gabriel
McDermott, James
Machine Learning
68W50, 90C59, 62J02
I.2.6
Many machine learning models perform well when making predictions within the training data range, but often struggle when required to extrapolate beyond it. Symbolic regression (SR) using genetic programming (GP) can generate flexible models but is prone to unreliable behaviour in extrapolation. This paper investigates whether adding synthetic data can help improve performance in such cases. We apply Kernel Density Estimation (KDE) to identify regions in the input space where the training data is sparse. Synthetic data is then generated in those regions using a knowledge distillation approach: a teacher model generates predictions on new input points, which are then used to train a student model. We evaluate this method across six benchmark datasets, using neural networks (NN), random forests (RF), and GP both as teacher models (to generate synthetic data) and as student models (trained on the augmented data). Results show that GP models can often improve when trained on synthetic data, especially in extrapolation areas. However, the improvement depends on the dataset and teacher model used. The most important improvements are observed when synthetic data from GPe is used to train GPp in extrapolation regions. Changes in interpolation areas show only slight changes. We also observe heterogeneous errors, where model performance varies across different regions of the input space. Overall, this approach offers a practical solution for better extrapolation. Note: An earlier version of this work appeared in the GECCO 2025 Workshop on Symbolic Regression. This arXiv version corrects several parts of the original submission.
title Can Synthetic Data Improve Symbolic Regression Extrapolation Performance?
topic Machine Learning
68W50, 90C59, 62J02
I.2.6
url https://arxiv.org/abs/2511.22794