Search Results for author: Aki Vehtari

Found 55 papers, 36 papers with code

Robust, Automated, and Accurate Black-box Variational Inference

1 code implementation29 Mar 2022 Manushi Welandawe, Michael Riis Andersen, Aki Vehtari, Jonathan H. Huggins

RAABBVI adaptively decreases the learning rate by detecting convergence of the fixed--learning-rate iterates, then estimates the symmetrized Kullback--Leiber (KL) divergence between the current variational approximation and the optimal one.

Bayesian Inference Stochastic Optimization +1

Pathfinder: Parallel quasi-Newton variational inference

5 code implementations9 Aug 2021 Lu Zhang, Bob Carpenter, Andrew Gelman, Aki Vehtari

Pathfinder returns draws from the approximation with the lowest estimated Kullback-Leibler (KL) divergence to the true posterior.

Pathfinder Variational Inference

Challenges for BBVI with Normalizing Flows

no code implementations ICML Workshop INNF 2021 Akash Kumar Dhaka, Alejandro Catalina, Manushi Welandawe, Michael Riis Andersen, Jonathan H. Huggins, Aki Vehtari

Current black-box variational inference (BBVI) methods require the user to make numerous design choices---such as the selection of variational objective and approximating family---yet there is little principled guidance on how to do so.

Variational Inference

Challenges and Opportunities in High Dimensional Variational Inference

no code implementations NeurIPS 2021 Akash Kumar Dhaka, Alejandro Catalina, Manushi Welandawe, Michael Riis Andersen, Jonathan H. Huggins, Aki Vehtari

Our framework and supporting experiments help to distinguish between the behavior of BBVI methods for approximating low-dimensional versus moderate-to-high-dimensional posteriors.

Variational Inference Vocal Bursts Intensity Prediction

Challenges and Opportunities in High-dimensional Variational Inference

no code implementations NeurIPS 2021 Akash Kumar Dhaka, Alejandro Catalina, Manushi Welandawe, Michael Riis Andersen, Jonathan Huggins, Aki Vehtari

Our framework and supporting experiments help to distinguish between the behavior of BBVI methods for approximating low-dimensional versus moderate-to-high-dimensional posteriors.

Variational Inference Vocal Bursts Intensity Prediction

Bayesian hierarchical stacking: Some models are (somewhere) useful

1 code implementation22 Jan 2021 Yuling Yao, Gregor Pirš, Aki Vehtari, Andrew Gelman

We show that stacking is most effective when model predictive performance is heterogeneous in inputs, and we can further improve the stacked mixture with a hierarchical model.

Bayesian Inference Time Series +1

What are the most important statistical ideas of the past 50 years?

1 code implementation30 Nov 2020 Andrew Gelman, Aki Vehtari

We review the most important statistical ideas of the past half century, which we categorize as: counterfactual causal inference, bootstrapping and simulation-based inference, overparameterized models and regularization, Bayesian multilevel models, generic computation algorithms, adaptive decision analysis, robust inference, and exploratory data analysis.

Causal Inference Methodology

Projection Predictive Inference for Generalized Linear and Additive Multilevel Models

1 code implementation14 Oct 2020 Alejandro Catalina, Paul-Christian Bürkner, Aki Vehtari

Projection predictive inference is a decision theoretic Bayesian approach that decouples model estimation from decision making.

Methodology Computation

Adaptive Path Sampling in Metastable Posterior Distributions

1 code implementation1 Sep 2020 Yuling Yao, Collin Cademartori, Aki Vehtari, Andrew Gelman

The normalizing constant plays an important role in Bayesian computation, and there is a large literature on methods for computing or approximating normalizing constants that cannot be evaluated in closed form.

Computation Methodology

Unbiased estimator for the variance of the leave-one-out cross-validation estimator for a Bayesian normal model with fixed variance

1 code implementation25 Aug 2020 Tuomas Sivula, Måns Magnusson, Aki Vehtari

We show that it is possible to construct an unbiased estimator considering a specific predictive performance measure and model.

Methodology

Uncertainty in Bayesian Leave-One-Out Cross-Validation Based Model Comparison

1 code implementation24 Aug 2020 Tuomas Sivula, Måns Magnusson, Aki Vehtari

We show that it is possible that the problematic skewness of the error distribution, which occurs when the models make similar predictions, does not fade away when the data size grows to infinity in certain situations.

Methodology

Stacking for Non-mixing Bayesian Computations: The Curse and Blessing of Multimodal Posteriors

1 code implementation22 Jun 2020 Yuling Yao, Aki Vehtari, Andrew Gelman

When working with multimodal Bayesian posterior distributions, Markov chain Monte Carlo (MCMC) algorithms have difficulty moving between modes, and default variational or mode-based approximate inferences will understate posterior uncertainty.

Bayesian Inference regression +2

Group Heterogeneity Assessment for Multilevel Models

1 code implementation6 May 2020 Topi Paananen, Alejandro Catalina, Paul-Christian Bürkner, Aki Vehtari

Many data sets contain an inherent multilevel structure, for example, because of repeated measurements of the same observational units.

A Decision-Theoretic Approach for Model Interpretability in Bayesian Framework

1 code implementation21 Oct 2019 Homayun Afrabandpey, Tomi Peltola, Juho Piironen, Aki Vehtari, Samuel Kaski

Through experiments on real-word data sets, using decision trees as interpretable models and Bayesian additive regression models as reference models, we show that for the same level of interpretability, our approach generates more accurate models than the alternative of restricting the prior.

Interpretable Machine Learning

Uncertainty-aware Sensitivity Analysis Using Rényi Divergences

1 code implementation17 Oct 2019 Topi Paananen, Michael Riis Andersen, Aki Vehtari

For nonlinear supervised learning models, assessing the importance of predictor variables or their interactions is not straightforward because it can vary in the domain of the variables.

Implicitly Adaptive Importance Sampling

2 code implementations20 Jun 2019 Topi Paananen, Juho Piironen, Paul-Christian Bürkner, Aki Vehtari

Adaptive importance sampling is a class of techniques for finding good proposal distributions for importance sampling.

Selecting the Metric in Hamiltonian Monte Carlo

1 code implementation28 May 2019 Ben Bales, Arya Pourzanjani, Aki Vehtari, Linda Petzold

We present a selection criterion for the Euclidean metric adapted during warmup in a Hamiltonian Monte Carlo sampler that makes it possible for a sampler to automatically pick the metric based on the model and the availability of warmup draws.

Computation Methodology

Bayesian leave-one-out cross-validation for large data

no code implementations24 Apr 2019 Måns Magnusson, Michael Riis Andersen, Johan Jonasson, Aki Vehtari

Model inference, such as model comparison, model checking, and model selection, is an important part of model development.

Model Selection

Active Learning for Decision-Making from Imbalanced Observational Data

1 code implementation10 Apr 2019 Iiris Sundin, Peter Schulam, Eero Siivola, Aki Vehtari, Suchi Saria, Samuel Kaski

Machine learning can help personalized decision support by learning models to predict individual treatment effects (ITE).

Active Learning Decision Making

Rank-normalization, folding, and localization: An improved $\widehat{R}$ for assessing convergence of MCMC

2 code implementations19 Mar 2019 Aki Vehtari, Andrew Gelman, Daniel Simpson, Bob Carpenter, Paul-Christian Bürkner

In this paper we show that the convergence diagnostic $\widehat{R}$ of Gelman and Rubin (1992) has serious flaws.

Computation Methodology

Approximate leave-future-out cross-validation for Bayesian time series models

1 code implementation17 Feb 2019 Paul-Christian Bürkner, Jonah Gabry, Aki Vehtari

One of the common goals of time series analysis is to use the observed series to inform predictions for future observations.

Methodology

Projective Inference in High-dimensional Problems: Prediction and Feature Selection

1 code implementation4 Oct 2018 Juho Piironen, Markus Paasiniemi, Aki Vehtari

This paper discusses predictive inference and feature selection for generalized linear models with scarce but high-dimensional data.

feature selection Vocal Bursts Intensity Prediction

Yes, but Did It Work?: Evaluating Variational Inference

1 code implementation ICML 2018 Yuling Yao, Aki Vehtari, Daniel Simpson, Andrew Gelman

While it's always possible to compute a variational approximation to a posterior distribution, it can be difficult to discover problems with this approximation.

Variational Inference

Bayesian Estimation of Gaussian Graphical Models with Projection Predictive Selection

1 code implementation17 Jan 2018 Donald R. Williams, Juho Piironen, Aki Vehtari, Philippe Rast

Here we introduce a Bayesian method for estimating sparse matrices, in which conditional relationships are determined with projection predictive selection.

Applications Methodology

Variable selection for Gaussian processes via sensitivity analysis of the posterior predictive distribution

2 code implementations21 Dec 2017 Topi Paananen, Juho Piironen, Michael Riis Andersen, Aki Vehtari

Variable selection for Gaussian process models is often done using automatic relevance determination, which uses the inverse length-scale parameter of each input variable as a proxy for variable relevance.

Gaussian Processes Variable Selection

Iterative Supervised Principal Components

no code implementations17 Oct 2017 Juho Piironen, Aki Vehtari

In high-dimensional prediction problems, where the number of features may greatly exceed the number of training instances, fully Bayesian approach with a sparsifying prior is known to produce good results but is computationally challenging.

Methodology

Visualization in Bayesian workflow

2 code implementations5 Sep 2017 Jonah Gabry, Daniel Simpson, Aki Vehtari, Michael Betancourt, Andrew Gelman

Bayesian data analysis is about more than just computing a posterior distribution, and Bayesian visualization is about more than trace plots of Markov chains.

Methodology Applications

Nudged elastic band calculations accelerated with Gaussian process regression

no code implementations14 Jun 2017 Olli-Pekka Koistinen, Freyja B. Dagbjartsdóttir, Vilhjálmur Ásgeirsson, Aki Vehtari, Hannes Jónsson

A Gaussian process model also provides an uncertainty estimate for the approximate energy surface, and this can be used to focus the calculations on the lesser-known part of the path, thereby reducing the number of needed energy and force evaluations to a half in the present calculations.

Atomic Forces regression

Using stacking to average Bayesian predictive distributions

2 code implementations6 Apr 2017 Yuling Yao, Aki Vehtari, Daniel Simpson, Andrew Gelman

The widely recommended procedure of Bayesian model averaging is flawed in the M-open setting in which the true data-generating process is not one of the candidate models being fit.

Methodology Computation

Correcting boundary over-exploration deficiencies in Bayesian optimization with virtual derivative sign observations

1 code implementation4 Apr 2017 Eero Siivola, Aki Vehtari, Jarno Vanhatalo, Javier González, Michael Riis Andersen

Bayesian optimization (BO) is a global optimization strategy designed to find the minimum of an expensive black-box function, typically defined on a compact subset of $\mathcal{R}^d$, by using a Gaussian process (GP) as a surrogate model for the objective.

Bayesian Optimization

Efficient acquisition rules for model-based approximate Bayesian computation

no code implementations3 Apr 2017 Marko Järvenpää, Michael U. Gutmann, Arijus Pleska, Aki Vehtari, Pekka Marttinen

We propose to compute the uncertainty in the ABC posterior density, which is due to a lack of simulations to estimate this quantity accurately, and define a loss function that measures this uncertainty.

Bayesian Inference Bayesian Optimisation +1

Minimum energy path calculations with Gaussian process regression

no code implementations30 Mar 2017 Olli-Pekka Koistinen, Emile Maras, Aki Vehtari, Hannes Jónsson

The calculation of minimum energy paths for transitions such as atomic and/or spin re-arrangements is an important task in many contexts and can often be used to determine the mechanism and rate of transitions.

regression

Gaussian process modeling in approximate Bayesian computation to estimate horizontal gene transfer in bacteria

no code implementations20 Oct 2016 Marko Järvenpää, Michael Gutmann, Aki Vehtari, Pekka Marttinen

Approximate Bayesian computation (ABC) can be used for model fitting when the likelihood function is intractable but simulating from the model is feasible.

Model Selection

Chained Gaussian Processes

1 code implementation18 Apr 2016 Alan D. Saul, James Hensman, Aki Vehtari, Neil D. Lawrence

Gaussian process models are flexible, Bayesian non-parametric approaches to regression.

Additive models Gaussian Processes

Bayesian inference for spatio-temporal spike-and-slab priors

no code implementations15 Sep 2015 Michael Riis Andersen, Aki Vehtari, Ole Winther, Lars Kai Hansen

In this work, we address the problem of solving a series of underdetermined linear inverse problems subject to a sparsity constraint.

Bayesian Inference

Practical Bayesian model evaluation using leave-one-out cross-validation and WAIC

7 code implementations16 Jul 2015 Aki Vehtari, Andrew Gelman, Jonah Gabry

Leave-one-out cross-validation (LOO) and the widely applicable information criterion (WAIC) are methods for estimating pointwise out-of-sample prediction accuracy from a fitted Bayesian model using the log-likelihood evaluated at the posterior simulations of the parameter values.

Computation Methodology

Pareto Smoothed Importance Sampling

9 code implementations9 Jul 2015 Aki Vehtari, Daniel Simpson, Andrew Gelman, Yuling Yao, Jonah Gabry

Importance weighting is a general way to adjust Monte Carlo integration to account for draws from the wrong distribution, but the resulting estimate can be highly variable when the importance ratios have a heavy right tail.

Comparison of Bayesian predictive methods for model selection

no code implementations30 Mar 2015 Juho Piironen, Aki Vehtari

From a predictive viewpoint, best results are obtained by accounting for model uncertainty by forming the full encompassing model, such as the Bayesian model averaging solution over the candidate models.

Model Selection

Bayesian leave-one-out cross-validation approximations for Gaussian latent variable models

no code implementations23 Dec 2014 Aki Vehtari, Tommi Mononen, Ville Tolvanen, Tuomas Sivula, Ole Winther

The future predictive performance of a Bayesian model can be estimated using Bayesian cross-validation.

Expectation propagation as a way of life: A framework for Bayesian inference on partitioned data

2 code implementations16 Dec 2014 Aki Vehtari, Andrew Gelman, Tuomas Sivula, Pasi Jylänki, Dustin Tran, Swupnil Sahai, Paul Blomstedt, John P. Cunningham, David Schiminovich, Christian Robert

A common divide-and-conquer approach for Bayesian computation with big data is to partition the data, perform local inference for each piece separately, and combine the results to obtain a global posterior approximation.

Bayesian Inference

Approximate Inference for Nonstationary Heteroscedastic Gaussian process Regression

no code implementations22 Apr 2014 Ville Tolvanen, Pasi Jylänki, Aki Vehtari

This paper presents a novel approach for approximate integration over the uncertainty of noise and signal variances in Gaussian process (GP) regression.

regression

Expectation Propagation for Neural Networks with Sparsity-promoting Priors

no code implementations27 Mar 2013 Pasi Jylänki, Aapo Nummenmaa, Aki Vehtari

Comparisons are made to two alternative models with ARD priors: a Gaussian process with a NN covariance function and marginal maximum a posteriori estimates of the relevance parameters, and a NN with Markov chain Monte Carlo integration over all the unknown model parameters.

Bayesian Modeling with Gaussian Processes using the GPstuff Toolbox

1 code implementation25 Jun 2012 Jarno Vanhatalo, Jaakko Riihimäki, Jouni Hartikainen, Pasi Jylänki, Ville Tolvanen, Aki Vehtari

The prior over functions is defined implicitly by the mean and covariance function, which determine the smoothness and variability of the function.

Gaussian Processes

Gaussian process regression with Student-t likelihood

no code implementations NeurIPS 2009 Jarno Vanhatalo, Pasi Jylänki, Aki Vehtari

In this work, we discuss the properties of a Gaussian process regression model with the Student-t likelihood and utilize the Laplace approximation for approximate inference.

regression

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