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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.

168,657 papers · 148 categories

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85170255340 · Jun 202019922001200920172026
48 results for Vecchia's Approximation

Bayesian optimization technique scaled using Vecchia approximations.

problem Scalability issue with Gaussian process surrogate models in Bayesian optimization.
method Adapted Vecchia approximation from spatial statistics to Gaussian processes, developed improvements and extensions.
result Methods compared favorably to state-of-the-art on various test functions and reinforcement learning problems.

New iterative methods improve Vecchia-Laplace approximations for large data sets.

problem Inaccurate and slow Vecchia-Laplace approximations for large data sets.
method Iterative methods to improve Vecchia-Laplace approximations, including preconditioners and novel methods for predictive variances.
result Order of magnitude speed-up and threefold increase in prediction accuracy compared to state-of-the-art methods.

Novel neural GP kernels learn stable, flexible covariance structures.

problem Scalable and flexible covariance kernels for Gaussian processes.
method Directly learn kriging coefficients and conditional standard deviations using deep neural architectures exploiting permutation-equivariant structure.
result Improved training stability and data efficiency with expressive, non-stationary kernels.

A scalable algorithm for GP regression selects relevant covariates efficiently.

problem Scalable variable selection in large GP regression models.
method VGPR algorithm using Vecchia approximation for sparse precision matrix, mini-batch subsampling.
result Improved scalability and accuracy in selecting relevant covariates.

Vecchia approximations provide the best accuracy-runtime trade-off for Gaussian process approximations.

problem High computational cost of Gaussian processes for large data sets.
method Systematic comparison of different Gaussian process approximations.
result Vecchia approximations consistently provide the best accuracy-runtime trade-off.

We derive a single pass algorithm for computing the gradient and Fisher information of Vecchia's Gaussian process loglikelihood approximation, which provides a computationally efficient means for applying the Fisher scoring algorithm for maximizing the loglikelihood. The advantages of the optimization techniques are de…

2019-05-20abs ↗pdf ↗

New iterative methods improve scalability of Gaussian process approximations for large data.

problem Scalability issues in Gaussian process approximations for large spatial data.
method Iterative methods combined with preconditioners to reduce computational costs.
result Preconditioners accelerate convergence and improve predictive variances.

Improved spatial distribution learning with Bayesian transport maps and parametric shrinkage.

problem Learning non-Gaussian spatial distributions with limited training data.
method Proposed ShrinkTM approach using Bayesian transport maps with parametric shrinkage.
result ShrinkTM outperforms existing BTM, especially with few training samples.

This paper develops a fast algorithm for solving nonlinear PDEs using sparse Cholesky factorization.

problem Efficiently solving nonlinear PDEs with Gaussian processes and kernel methods.
method Sparse Cholesky factorization for near-linear complexity.
result Near-linear complexity algorithm for working with kernel matrices of nonlinear PDEs.

TERA method speeds up derivative Gaussian processes in high dimensions.

problem High-dimensional function evaluations and gradient computations are computationally expensive.
method TERA uses exact gradient reduction to decouple nn and dd from the computational cost.
result TERA achieves state-of-the-art predictive accuracy with orders of magnitude faster computation.

New method preserves GCM spatial dependencies for better climate projections.

problem Systemic biases in GCM output and loss of spatial/temporal dependencies.
method SPECD approach using Vecchia approximation and semi-parametric quantile regression.
result SPECD preserves key marginal and joint distribution properties of precipitation and temperature.

Spatial statisticians and quantitative investors use the same mathematical object: a Schur complement, damped by one parameter.

problem The Schur complement is used in both spatial modeling and portfolio allocation, but the parameters are different.
method The Schur complement is interpreted as reliability shrinkage of a conditional Gaussian.
result The Schur complement is the same in both applications.

The study provides conditions for approximating Riemannian manifolds with polyhedral metrics.

problem Approximating Riemannian manifolds with polyhedral metrics.
method Conditions on curvature tensors for Lipschitz and local polyhedral approximations.
result Conditions are sufficient for local polyhedral approximations, conjectured to be sufficient for global approximations.

We consider in this paper the optimal approximations of convex univariate functions with feed-forward Relu neural networks. We are interested in the following question: what is the minimal approximation error given the number of approximating linear pieces? We establish the necessary and sufficient conditions and uniqu…

2019-09-09abs ↗pdf ↗

We study sparse approximate solutions to convex optimization problems. It is known that in many engineering applications researchers are interested in an approximate solution of an optimization problem as a linear combination of elements from a given system of elements. There is an increasing interest in building such …

2012-06-02abs ↗pdf ↗

Softmax attention approximates complex functions and subsumes many known universal approximators.

problem Universal approximation of continuous sequence-to-sequence functions.
method Interpolation-based analysis of attention's internal mechanism, showing its ability to approximate ReLU functions.
result Softmax attention is a universal approximator for continuous sequence-to-sequence functions.

Deviation inequalities for stochastic approximation methods.

problem Establishing bounds on the deviation of stochastic approximation methods.
method Martingale approximation method for separately Lipschitz functions.
result Established various deviation inequalities for stochastic approximation by averaging and minimization.

Approximate symmetries of geodesic equations on 2-spheres are studied. These are the symmetries of the perturbed geodesic equations which represent approximate path of a particle rather than exact path. After giving the exact symmetries of the geodesic equations, two different approaches to study the approximate symmet…

2010-05-09abs ↗pdf ↗

We are concerned with an approximation problem for a symmetric positive semidefinite matrix due to motivation from a class of nonlinear machine learning methods. We discuss an approximation approach that we call {matrix ridge approximation}. In particular, we define the matrix ridge approximation as an incomplete matri…

2013-12-17abs ↗pdf ↗

Adaptive approximations improve variational inference for complex models.

problem Efficiently approximate marginal distributions and partition functions in complex probabilistic models.
method Two classes of adaptive approximations that include Bethe, tree-reweighted, and convex free energies.
result Proposed approximations automatically adapt to a given model and outperform existing methods.

Non-negative L1L_1-approximating polynomials for Gaussian distributions are proven for certain classes of sets.

problem Existence of non-negative L1L_1-approximating polynomials for Gaussian distributions.
method Proving the existence of degree-kk non-negative polynomials that approximate indicator functions of sets with Gaussian surface area in L1L_1-norm.
result Proves the existence of non-negative L1L_1-approximating polynomials for certain classes of sets with Gaussian surface area.

Paper introduces new approximations for lognormal sums, matching comonotonicity and moments.

problem Approximating sums of lognormal random variables accurately.
method Introduces new approximations based on weighted distribution theory, emphasizing comonotonicity and moment matching.
result Approximations perform better than classical methods, especially in the right tail of the distribution.

Paper analyzes normal approximation for two-timescale stochastic algorithms, revealing interaction between fast and slow timescales.

problem Non-asymptotic bounds for accuracy of normal approximation in linear two-timescale stochastic approximation algorithms.
method Established bounds for normal approximation in terms of convex distance, focusing on last iterate and Polyak-Ruppert averaging.
result Normal approximation rate for the last iterate improves with increased timescale separation, while it decreases in the averaged setting.

One-pass algorithm finds small subset for p\ell_p subspace approximation with additive error.

problem Finding a small subset of data points for p\ell_p subspace approximation.
method One-pass subset selection with additive approximation guarantee for p[1,)p \in [1, \infty).
result First one-pass algorithm with additive error for p\ell_p subspace approximation.

We are interested in approximation of a multivariate function f(x1,,xd)f(x_1,\dots,x_d) by linear combinations of products u1(x1)ud(xd)u^1(x_1)\cdots u^d(x_d) of univariate functions ui(xi)u^i(x_i), i=1,,di=1,\dots,d. In the case d=2d=2 it is a classical problem of bilinear approximation. In the case of approximation in the L2L_2 space the bili…

2014-09-04abs ↗pdf ↗

A new method for efficient Gaussian process inference using sparse approximations.

problem Scalable and accurate inference for latent Gaussian processes.
method Variational approximation with sparse inverse Cholesky factors and double Kullback-Leibler minimization.
result The proposed method can achieve highly accurate approximations with polylogarithmic time complexity.

The paper defines a new concept of approximability for Lagrangian submanifolds.

problem Understanding the approximability of Lagrangian submanifolds.
method Introducing a new notion of categorical approximability for metric spaces, showing it applies to specific types of Lagrangian submanifolds.
result Examples of Lagrangian submanifolds are found that are approximable but not precompact.