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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.

168,695 papers · 148 categories

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126251377502 · Jun 202019922001200920172026
48 results for matrix parameters

Proposes a new method for selecting regularization parameters in sparse precision matrix estimation.

problem Selecting an appropriate regularization parameter for sparse precision matrix estimation.
method Developed a closed-form matrix-valued regularization parameter based on the sampling distribution of optimality conditions.
result The proposed method achieves comparable estimation accuracy and superior support recovery to cross-validation, with significant runtime improvements.

The Random Parameters model was proposed to explain the structure of the covariance matrix in problems where most, but not all, of the eigenvalues of the covariance matrix can be explained by Random Matrix Theory. In this article, we explore other properties of the model, like the scaling of its PDF as one take larger …

2007-10-29abs ↗pdf ↗

Matrix SMD converges to unique solution minimizing Bregman divergence.

problem High-dimensional multi-output classification and matrix completion problems.
method Stochastic Mirror Descent with matrix parameters and matrix mirror functions.
result Matrix SMD converges exponentially to the unique solution minimizing Bregman divergence.

This paper compares imputation and direct parameter estimation methods for missing data in correlation matrix visualization.

problem Missing data challenges in estimating correlation coefficients for accurate visualization.
method Comparison of imputation and direct parameter estimation methods for handling missing data.
result Direct parameter estimation (DPER) outperforms imputation for accurate correlation matrix visualization.

We present two simple ways of reducing the number of parameters and accelerating the training of large Long Short-Term Memory (LSTM) networks: the first one is "matrix factorization by design" of LSTM matrix into the product of two smaller matrices, and the second one is partitioning of LSTM matrix, its inputs and stat…

2017-03-31abs ↗pdf ↗

Bayesian deep learning avoids underfitting by projecting onto null space of generalized Gauss-Newton matrix.

problem Bayesian deep learning often underfits, leading to less accurate predictions than point estimates.
method Proposes a matrix-free algorithm to project onto the null space of the generalized Gauss-Newton matrix, ensuring Bayesian predictions do not underfit.
result The method scales to large models, including vision transformers with 28 million parameters, and avoids underfitting.

Study improves fractional posterior for 1-bit matrix completion.

problem Estimating a binary matrix from observed entries.
method Fractional posterior approach with low-rank factorization and spectral scaled Student priors.
result Concentration results for fractional posterior, demonstrating effectiveness in matrix recovery.

Paper proposes an efficient algorithm for nonnegative binary matrix factorization.

problem Decomposing binary data using matrix factorization.
method Majorization-minimization algorithm with Beta prior for improved performance.
result Proposed algorithm offers excellent trade-off between performance, complexity, and interpretability.

Most of machine learning deals with vector parameters. Ideally we would like to take higher order information into account and make use of matrix or even tensor parameters. However the resulting algorithms are usually inefficient. Here we address on-line learning with matrix parameters. It is often easy to obtain onlin…

2015-06-16abs ↗pdf ↗

Due to the growing ubiquity of unlabeled data, learning with unlabeled data is attracting increasing attention in machine learning. In this paper, we propose a novel semi-supervised kernel learning method which can seamlessly combine manifold structure of unlabeled data and Regularized Least-Squares (RLS) to learn a ne…

2012-03-15abs ↗pdf ↗

The paper reduces the complexity of financial market correlation matrices to a 2x2 matrix.

problem Reducing the complexity of financial market correlation matrices for easier analysis.
method Sectorial coarse graining followed by averaging over blocks of stocks.
result Averaging over blocks of stocks results in a reduced matrix with specific properties.

Recommender systems can be formulated as a matrix completion problem, predicting ratings from user and item parameter vectors. Optimizing these parameters by subsampling data becomes difficult as the number of users and items grows. We develop a novel approach to generate all latent variables on demand from the ratings…

2018-07-05abs ↗pdf ↗

A well-recognized limitation of kernel learning is the requirement to handle a kernel matrix, whose size is quadratic in the number of training examples. Many methods have been proposed to reduce this computational cost, mostly by using a subset of the kernel matrix entries, or some form of low-rank matrix approximatio…

2014-11-05abs ↗pdf ↗

The paper analyzes how Gaussian kernel parameters affect posterior covariance in Gaussian processes.

problem Understanding the influence of Gaussian kernel parameters on posterior covariance in Gaussian processes.
method Geometric analysis and a posteriori error estimation techniques from adaptive finite element methods.
result The bandwidth parameter and spatial distribution of observations significantly influence posterior covariance and its matrix.

EPMF factorizes matrices by adjusting their entries to match a specified power.

problem Factorizing matrices with adjusted entries to match a specified power.
method Analyzes the computational complexity of exact and approximate EPMF problems.
result Exact EPMF is strongly NP-hard, but can be solved in polynomial time when rank is fixed.

DPERC efficiently estimates covariance matrices for mixed data with missing values.

problem Estimating covariance matrices for datasets with missing values and mixed features.
method Direct Parameter Estimation for Randomly Missing Data with Categorical Features (DPERC).
result DPERC outperforms other methods in estimating covariance matrices for mixed data with missing values.

We consider the related tasks of matrix completion and matrix approximation from missing data and propose adaptive sampling procedures for both problems. We show that adaptive sampling allows one to eliminate standard incoherence assumptions on the matrix row space that are necessary for passive sampling procedures. Fo…

2014-07-14abs ↗pdf ↗

In this paper, we develop a parameter estimation method for factorially parametrized models such as Factorial Gaussian Mixture Model and Factorial Hidden Markov Model. Our contributions are two-fold. First, we show that the emission matrix of the standard Factorial Model is unidentifiable even if the true assignment ma…

2015-08-18abs ↗pdf ↗

Study shows deterministic equivalent for neural network kernel convergence.

problem Understanding convergence of neural network kernels.
method Analyzes empirical spectral distribution of Conjugate Kernel, proving convergence to a deterministic limit.
result Obtains a deterministic equivalent for the Stieltjes transform and resolvent of the Conjugate Kernel.

PrecGD restores linear convergence in over-parameterized nonconvex matrix factorization.

problem Slow convergence of local search algorithms in over-parameterized nonconvex matrix factorization.
method Preconditioned Gradient Descent (PrecGD) with an inexpensive 2\ell_2 regularization.
result PrecGD restores linear convergence rate even in the over-parameterized case.

The paper proposes AIS for Bayesian inversion of multioutput signals with covariance estimation.

problem Performing uncertainty analysis of covariance matrices in Bayesian inversion problems for multioutput signals.
method Adaptive Importance Sampling (AIS) scheme, split variables, frequentist approach for noise covariance, prior density over covariance matrix.
result Estimation of model parameters and covariance matrix of noise.

Matrix completion is a modern missing data problem where both the missing structure and the underlying parameter are high dimensional. Although missing structure is a key component to any missing data problems, existing matrix completion methods often assume a simple uniform missing mechanism. In this work, we study ma…

2018-12-19abs ↗pdf ↗

Estimates matrix trace optimization with statistical learning theory.

problem Optimizing trace of parameter-dependent matrices.
method Monte Carlo estimator with bounds derived from epsilon nets and generic chaining.
result Predicts small sampling amount for matrices with small off-diagonal mass.

This paper solves the convergence problem for estimating MGGD parameters with a convex formulation.

problem Establishing convergence properties for estimating MGGD parameters with unknown mean and precision matrix.
method Proposes a convex formulation with well-established convergence properties for robust estimation in noisy scenarios.
result Demonstrates improved accuracy in precision and covariance matrix estimation compared to existing methods.

We consider the problem of matrix completion with side information (\textit{inductive matrix completion}). In real-world applications many side-channel features are typically non-informative making feature selection an important part of the problem. We incorporate feature selection into inductive matrix completion by p…

2018-04-27abs ↗pdf ↗

MuonEq improves training of matrix-valued parameters by rebalancing momentum before orthogonalization.

problem Training matrix-valued parameters with orthogonalized-update optimizers like Muon.
method MuonEq introduces three lightweight pre-orthogonalization equilibration schemes: two-sided row/column normalization (RC), row normalization (R), and column normalization (C).
result Row/column normalization acts as a zeroth-order surrogate for whitening and improves the geometry seen by orthogonalization.

New method proves asymptotic normality for matrix sensing problems.

problem Proving asymptotic normality for matrix sensing under general convex losses.
method Riemannian geometry to handle degeneracy of the Hessian due to rotational symmetry.
result Proves n(φ0φ)DN(0,(H)1)\sqrt{n}(φ^0-φ^*)\xrightarrow{D}N(0,(H^*)^{-1}) as non o\infty.

Two Fisher information matrix estimators are analyzed for neural networks, focusing on their variances and trade-offs.

problem Estimating the Fisher information matrix in neural networks due to its high computational cost.
method Examined two popular diagonal Fisher information matrix estimators and their variances in neural networks for regression and classification.
result The variances of the estimators depend on the non-linearity with respect to different parameter groups and should not be neglected.

The paper studies the loss landscape of regularized deep matrix factorization, revealing unique and sharp minimizers.

problem Understanding the loss landscape and minimizers of regularized deep matrix factorization problems.
method Theoretical analysis of 2\ell^2-regularized deep matrix factorization/deep linear network training problems with squared-error loss.
result The unique end-to-end minimizer exists for all target matrices except for a set of Lebesgue measure zero.

Muon optimizer outperforms GD in neural networks.

problem Optimizing matrix-structured parameters in neural networks.
method Muon optimizer specifically designed for matrix parameters, analyzing convergence rate and low-rank Hessian structure.
result Muon can outperform Gradient Descent due to its ability to leverage the low-rank structure of Hessian matrices.

Matrix completion models are among the most common formulations of recommender systems. Recent works have showed a boost of performance of these techniques when introducing the pairwise relationships between users/items in the form of graphs, and imposing smoothness priors on these graphs. However, such techniques do n…

2017-04-22abs ↗pdf ↗

Adaptive regularization methods pre-multiply a descent direction by a preconditioning matrix. Due to the large number of parameters of machine learning problems, full-matrix preconditioning methods are prohibitively expensive. We show how to modify full-matrix adaptive regularization in order to make it practical and e…

2018-06-08abs ↗pdf ↗

A Kronecker product model is the set of visible marginal probability distributions of an exponential family whose sufficient statistics matrix factorizes as a Kronecker product of two matrices, one for the visible variables and one for the hidden variables. We estimate the dimension of these models by the maximum rank …

2015-11-10abs ↗pdf ↗