Biconvex Biclustering
Organizations: Department of Statistical Science, Duke University · School of Statistics, University of Minnesota · Department of Biostatistics, University of California Los Angeles
Abstract
This article proposes a biconvex modification to convex biclustering in order to improve its performance in high-dimensional settings. In contrast to heuristics that discard a subset of noisy features a priori, our method jointly learns and accordingly weighs informative features while discovering biclusters. Moreover, the method is adaptive to the data, and is accompanied by an efficient algorithm based on proximal alternating minimization, complete with detailed guidance on hyperparameter tuning and efficient solutions to optimization subproblems. These contributions are theoretically grounded; we establish finite-sample bounds on the objective function under sub-Gaussian errors, and generalize these guarantees to cases where input affinities need not be uniform. Extensive simulation results reveal our method consistently recovers underlying biclusters while weighing and selecting features appropriately, outperforming peer methods. An application to a gene microarray dataset of lymphoma samples recovers biclusters matching an underlying classification, while giving additional interpretation to the mRNA samples via the column groupings and fitted weights.
Figures & tables
| Label | Size | Mean Weight | Max Weight | Highest Weight mRNA Sample |
|---|---|---|---|---|
| A | 276 | 1.48 | 2.82 | Ki-67 |
| B | 156 | 1.26 | 2.11 | NM23-H1 (NDP kinase A) |
| C | 319 | 1.23 | 2.05 | Cathepsin B |
| D | 81 | 1.23 | 2.04 | Beta-actin |
| E | 111 | 1.20 | 1.81 | Ras GTPase-activating protein |
| F | 437 | 1.17 | 1.98 | MEK Kinase 1 (MEKK1) |
Clustering
Clustering groups data points by shared structure, developing methods to discover, validate, and interpret groups across diverse data and constraints.
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