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NWTOPT — A hyperparameter optimization approach for selection of environmental model solver settings

February 14, 2022

Hyperparameter optimization approaches were applied to improve performance and accuracy of groundwater flow models. Freely available new software, NWTOPT, is described that uses Tree of Parzen Estimators (TPE) and Random Search algorithms to optimize MODFLOW-NWTs solver settings. We ran 3500 trials on a steady-state and transient model. To quantify the performance of candidate solver settings, we defined a loss function based on time elapsed and mass balance error of the MODFLOW-NWT forward run. Before optimization the steady- state model ran in ~12 min and the transient model ran in ~5 h with acceptable mass balance error (<1%). After optimization runtimes were reduced to ~2.7 min (steady state) and ~48 min (transient) with errors below 0.1%. In both cases TPE found hyperparameters that resulted in faster running and lower error models than those found by Random Search. The time to complete the optimization trials was also shorter with the TPE algorithm.

Citation Information

Publication Year 2022
Title NWTOPT — A hyperparameter optimization approach for selection of environmental model solver settings
DOI 10.1016/j.envsoft.2021.105250
Authors Max William Newcomer, Randall J. Hunt
Publication Type Article
Publication Subtype Journal Article
Series Title Environmental Modelling and Software
Series Number
Index ID 70228602
Record Source USGS Publications Warehouse
USGS Organization Upper Midwest Water Science Center

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