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arXiv research

A locally-built, LLM-digested index of recent arXiv papers in quant finance, geometry/topology, and statistical ML — keyword search served straight from SQLite on this machine.

169,051 papers · 148 categories

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152304456608 · Jun 202019922001200920182026
48 results for empirical leverage scores

We explain theoretically a curious empirical phenomenon: "Approximating a matrix by deterministically selecting a subset of its columns with the corresponding largest leverage scores results in a good low-rank matrix surrogate". To obtain provable guarantees, previous work requires randomized sampling of the columns wi…

2014-04-06abs ↗pdf ↗

This paper improves random feature sampling using empirical leverage scores.

problem Optimizing the number of features for kernel approximation and supervised learning.
method Uses empirical leverage scores to optimize feature sampling.
result Empirical sampling of random features using leverage scores outperforms vanilla Monte Carlo sampling.

Efficiently approximates statistical leverage scores for faster KRR.

problem Accurately estimating statistical leverage scores for fast KRR.
method Analytic formula for statistical leverage scores, leveraging kernel spectral density.
result Linear time approximation with theoretical guarantees, significantly faster than existing methods.

Active learning aims to obtain a classifier of high accuracy by using fewer label requests in comparison to passive learning by selecting effective queries. Many active learning methods have been developed in the past two decades, which sample queries based on informativeness or representativeness of unlabeled data poi…

2015-07-15abs ↗pdf ↗

SALSA efficiently approximates leverage scores for big data, improving ARMA model fitting.

problem Efficiently approximating leverage scores for large matrices.
method Sequential approximate leverage-score algorithm (SALSA) using randomized numerical linear algebra.
result SALSA approximates leverage scores within (1+O(ε))(1 + O({\varepsilon})) with high probability.

Improved sample complexity for diffusion models without needing empirical risk minimizers.

problem Theoretical limitations in sample complexity for diffusion models.
method Structured decomposition of score estimation error, eliminating dependence on neural network parameters.
result Achieved sample complexity bound of O(ε^(-4)) without empirical risk minimizer access.

LSAR efficiently estimates AR models for big time series data.

problem Efficiently analyzing large-scale time series data with high accuracy.
method Developed a fast algorithm to estimate leverage scores and an efficient LSAR algorithm for fitting AR models.
result LSAR algorithm finds maximum likelihood estimates with high probability and improved worst-case running time.

The statistical leverage scores of a complex matrix ACn×dA\in\mathbb{C}^{n\times d} record the degree of alignment between col(A)(A) and the coordinate axes in Cn\mathbb{C}^n. These score are used in random sampling algorithms for solving certain numerical linear algebra problems. In this paper we present a max-plus algebr…

2016-09-29abs ↗pdf ↗

Paper develops efficient methods for leverage score sampling and kernel ridge regression.

problem Efficiently sampling leverage scores for large matrices.
method Novel algorithm for leverage score sampling and kernel ridge regression solver.
result Proposed algorithms are the most efficient and accurate for leverage score sampling and kernel ridge regression.

This paper improves matrix completion by leveraging element importance and non-uniform sampling.

problem The challenge of completing low-rank matrices from noisy, subsampled measurements.
method Employing leverage scores to characterize element importance and devising a biased sampling procedure.
result Theoretical and empirical evidence shows that a smaller number of entries (about O(nrlog2(n))O(nr\log^2(n))) can recover a low-rank matrix with noise.

Generalizes leverage score sampling for neural networks, accelerating kernel methods and deep learning.

problem Accelerating kernel methods and deep learning training.
method Generalizes leverage score sampling to neural networks and proves equivalence to neural tangent kernel ridge regression.
result Equivalence between regularized neural network and neural tangent kernel ridge regression under leverage score sampling initialization.

We give the first algorithm for kernel Nyström approximation that runs in *linear time in the number of training points* and is provably accurate for all kernel matrices, without dependence on regularity or incoherence conditions. The algorithm projects the kernel onto a set of ss landmark points sampled by their *rid…

2016-05-24abs ↗pdf ↗

New active learning methods use statistical leverage scores to select examples efficiently.

problem Efficiently selecting labeled examples for high model accuracy with limited labeled data.
method Proposes ALEVS and DBALEVS methods based on statistical leverage scores.
result DBALEVS selects diverse, representative examples efficiently.

ScoreAG generates unrestricted adversarial images maintaining semantic integrity.

problem Limited robustness evaluations due to p\ell_p-norm constraints.
method Score-Based Adversarial Generation (ScoreAG) using score-based generative models.
result ScoreAG improves robustness assessments across multiple benchmarks.

Unified study of nine multi-output conformal methods with generalized scores.

problem Challenges in extending conformal prediction to multi-output problems.
method Nine conformal methods with generalized multi-output conformity scores.
result Generalized scores ensure asymptotic conditional coverage and exact finite-sample marginal coverage.

Parallel score matching accelerates DPM training and improves density estimation.

problem Extended training periods and limited modeling flexibility in DPMs.
method Partitioning the learning task into independent time sub-intervals and modeling the score at each time point separately.
result Significant acceleration of training process and improved density estimation performance.

A new method improves efficiency of conformal prediction for ensemble models.

problem Efficiently estimating uncertainty for ensemble models without distributional assumptions.
method Proposes a multivariate score function to merge prediction regions of individual models, reducing conservatism.
result Demonstrates more efficient prediction regions compared to existing methods.

Binary testing for softmax models requires many samples, similar to leverage score models.

problem Binary hypothesis testing for softmax models and leverage score models.
method Analyzing sample complexity and drawing analogies between models.
result Sample complexity is asymptotically \(O(ε^{-2})\), where \(ε\) is the distance between model parameters.

One popular method for dealing with large-scale data sets is sampling. For example, by using the empirical statistical leverage scores as an importance sampling distribution, the method of algorithmic leveraging samples and rescales rows/columns of data matrices to reduce the data size before performing computations on…

2013-06-23abs ↗pdf ↗

New method assesses individual training points' privacy risk without retraining.

problem Privacy vulnerability of individual training points in membership inference attacks.
method Derives a closed-form decomposition of individual black-box MIA vulnerability, extending to deep networks.
result Proposes a surrogate score operating on last-layer representations that requires only a single trained model.

Introduces VSMD to improve generative diffusion processes without high costs.

problem High training costs and scalability issues in generative diffusion processes.
method Introduces variational Schrödinger momentum diffusion (VSMD) with adaptively transport-optimized variational scores and critical-damping transform.
result Efficiently generates anisotropic shapes while maintaining transport efficacy, outperforming alternatives.

We use the score function for causal discovery, tackling challenges with hidden variables.

problem Causal discovery from observational data with hidden variables.
method Fine-tuning identifiability results, establishing conditions for inferring causal relations from the score, proposing a flexible algorithm.
result Empirical validation of the proposed algorithm for causal discovery on linear, nonlinear, and latent variable models.

Generative models solve medical imaging inverse problems without needing paired data.

problem Reconstructing medical images from partial measurements.
method Score-based generative models trained on medical images, then sampling to reconstruct images consistent with measurements and physical model.
result Comparable or better performance in CT and MRI tasks, with improved generalization to unknown measurement processes.

We derive optimal statistical and computational complexity bounds for exp-concave stochastic minimization in terms of the effective dimension. For common eigendecay patterns of the population covariance matrix, this quantity is significantly smaller than the ambient dimension. Our results reveal interesting connections…

2018-05-21abs ↗pdf ↗

We consider the problem of exact recovery of any m×nm\times n matrix of rank ϱ\varrho from a small number of observed entries via the standard nuclear norm minimization framework. Such low-rank matrices have degrees of freedom (m+n)ϱϱ2(m+n)\varrho - \varrho^2. We show that any arbitrary low-rank matrices can be recovered exa…

2015-03-22abs ↗pdf ↗

This work improves SGMs' convergence guarantees for semiconvex distributions with discontinuous gradients.

problem Establishing convergence guarantees for SGMs under weak regularity conditions.
method Developed non-asymptotic Wasserstein-2 convergence analysis for SGMs targeting semiconvex distributions with discontinuous gradients.
result Achieved optimal dependence of O(d)O(\sqrt{d}) on data dimension dd and convergence rate of order one.

Proposes MSS to identify causal structure from heterogeneous environments.

problem Distribution shifts between environments violate i.i.d. data assumption.
method Sparse mechanism shift hypothesis, score-based approach.
result Identifies entire causal structure with high probability.

Stein discrepancy improves UDA performance in low-data scenarios.

problem Improving model performance on unlabeled target domains with limited data.
method Proposes a novel UDA framework using Stein discrepancy, an asymmetric measure that depends on the target distribution through its score function.
result Consistently outperforms prior UDA approaches under limited target data across multiple benchmarks.

This paper explores adversarial robustness of flow-based generative models.

problem Robustness of flow-based generative models to adversarial attacks.
method Theoretical and empirical analysis of adversarial robustness for simple and complex flow-based models.
result Flow-based generative models are highly sensitive to adversarial attacks, but robustness can be significantly improved using hybrid adversarial training.

Random Fourier features is a widely used, simple, and effective technique for scaling up kernel methods. The existing theoretical analysis of the approach, however, remains focused on specific learning tasks and typically gives pessimistic bounds which are at odds with the empirical results. We tackle these problems an…

2018-06-24abs ↗pdf ↗