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.
We obtain the first positive results for bounded sample compression in the agnostic regression setting with the ℓp loss, where p∈[1,∞]. We construct a generic approximate sample compression scheme for real-valued function classes exhibiting exponential size in the fat-shattering dimension but independen…
Least Angle Regression is a promising technique for variable selection applications, offering a nice alternative to stepwise regression. It provides an explanation for the similar behavior of LASSO (ℓ1-penalized regression) and forward stagewise regression, and provides a fast implementation of both. The idea has…
We give improved algorithms for the ℓp-regression problem, minx∥x∥p such that Ax=b, for all p∈(1,2)∪(2,∞). Our algorithms obtain a high accuracy solution in O~p(m2p+∣p−2∣∣p−2∣)≤O~p(m31) iterations, where each iteration requires s…
This work provides efficient algorithms for approximating ℓ_p sensitivities and related statistics.
problem Estimating the importance of datapoints in high-dimensional datasets.
method Efficient algorithms for computing α-approximation of ℓ_1 sensitivities and total sensitivity using importance sampling and sensitivity computations.
result Real-world datasets have significantly lower intrinsic effective dimensionality than theoretical predictions.
Given a matrix A∈Rn×d and a vector b∈Rn, we consider the regression problem with ℓ∞ guarantees: finding a vector x′∈Rd such that ∥x′−x∗∥∞≤dε⋅∥Ax∗−b∥2⋅∥A†∥ where $x^*=\arg\min_{x\in \mathbb{R}^d}\|Ax-b\|…
In this paper, we discuss the statistical properties of the ℓq optimization methods (0<q≤1), including the ℓq minimization method and the ℓq regularization method, for estimating a sparse parameter from noisy observations in high-dimensional linear regression with either a deterministic or rando…
The ℓp linear regression problem is to minimize f(x)=∣∣Ax−b∣∣p over x∈Rd, where A∈Rn×d, b∈Rn, and p>0. To avoid overfitting and bound ∣∣x∣∣2, the constrained ℓp regression minimizes f(x) over every unit vector x∈Rd. This makes the pr…
The main contribution of the paper is a new approach to subspace clustering that is significantly more computationally efficient and scalable than existing state-of-the-art methods. The central idea is to modify the regression technique in sparse subspace clustering (SSC) by replacing the ℓ1 minimization with a g…
In recent years, stochastic gradient descent (SGD) methods and randomized linear algebra (RLA) algorithms have been applied to many large-scale problems in machine learning and data analysis. We aim to bridge the gap between these two methods in solving constrained overdetermined linear regression problems---e.g., $\el…
Regularized linear regression improves binary classification performance, especially with ridge and ℓ1 regularization.
problem Improving binary classification accuracy with noisy labels.
method Systematic study of regularization strengths on linear classifiers trained on noisy binary classification data.
result Ridge regression consistently improves classification error, while ℓ1 regularization can induce sparsity and ℓ∞ regularization can concentrate weights to two values.
We characterize the effectiveness of a classical algorithm for recovering the Markov graph of a general discrete pairwise graphical model from i.i.d. samples. The algorithm is (appropriately regularized) maximum conditional log-likelihood, which involves solving a convex program for each node; for Ising models this is …
Sparse linear regression -- finding an unknown vector from linear measurements -- is now known to be possible with fewer samples than variables, via methods like the LASSO. We consider the multiple sparse linear regression problem, where several related vectors -- with partially shared support sets -- have to be recove…
In this paper, we consider the problem of linear regression with heavy-tailed distributions. Different from previous studies that use the squared loss to measure the performance, we choose the absolute loss, which is capable of estimating the conditional median. To address the challenge that both the input and output c…
In multivariate regression, a K-dimensional response vector is regressed upon a common set of p covariates, with a matrix B∗∈Rp×K of regression coefficients. We study the behavior of the multivariate group Lasso, in which block regularization based on the ℓ1/ℓ2 norm is used for supp…
In this paper we consider the problem of grouped variable selection in high-dimensional regression using ℓ1−ℓq regularization (1≤q≤∞), which can be viewed as a natural generalization of the ℓ1−ℓ2 regularization (the group Lasso). The key condition is that the dimensionality pn can…
Least squares kernel based methods have been widely used in regression problems due to the simple implementation and good generalization performance. Among them, least squares support vector regression (LS-SVR) and extreme learning machine (ELM) are popular techniques. However, the noise sensitivity is a major bottlene…
The ℓ1-penalized method, or the Lasso, has emerged as an important tool for the analysis of large data sets. Many important results have been obtained for the Lasso in linear regression which have led to a deeper understanding of high-dimensional statistical problems. In this article, we consider a class of weigh…
Feature selection is a standard approach to understanding and modeling high-dimensional classification data, but the corresponding statistical methods hinge on tuning parameters that are difficult to calibrate. In particular, existing calibration schemes in the logistic regression framework lack any finite sample guara…
We study the robustness properties of ℓ1 norm minimization for the classical linear regression problem with a given design matrix and contamination restricted to the dependent variable. We perform a fine error analysis of the ℓ1 estimator for measurements errors consisting of outliers coupled with noise. We…
We demonstrate that the primal-dual witness proof method may be used to establish variable selection consistency and ℓ∞-bounds for sparse regression problems, even when the loss function and/or regularizer are nonconvex. Using this method, we derive two theorems concerning support recovery and ℓ∞-…
The popularity of algorithms based on Extreme Learning Machine (ELM), which can be used to train Single Layer Feedforward Neural Networks (SLFN), has increased in the past years. They have been successfully applied to a wide range of classification and regression tasks. The most commonly used methods are the ones based…
Recent research has studied the role of sparsity in high dimensional regression and signal reconstruction, establishing theoretical limits for recovering sparse models from sparse data. This line of work shows that ℓ1-regularized least squares regression can accurately estimate a sparse linear model from n nois…
Recently, Mahoney and Orecchia demonstrated that popular diffusion-based procedures to compute a quick \emph{approximation} to the first nontrivial eigenvector of a data graph Laplacian \emph{exactly} solve certain regularized Semi-Definite Programs (SDPs). In this paper, we extend that result by providing a statistica…