Search Results for author: Marc A. Suchard

Found 11 papers, 8 papers with code

On the importance of assessing topological convergence in Bayesian phylogenetic inference

no code implementations18 Feb 2024 Marius Brusselmans, Luiz Max Carvalho, Samuel L. Hong, Jiansi Gao, Frederick A. Matsen IV, Andrew Rambaut, Philippe Lemey, Marc A. Suchard, Gytis Dudas, Guy Baele

Modern phylogenetics research is often performed within a Bayesian framework, using sampling algorithms such as Markov chain Monte Carlo (MCMC) to approximate the posterior distribution.

Automatic differentiation is no panacea for phylogenetic gradient computation

2 code implementations3 Nov 2022 Mathieu Fourment, Christiaan J. Swanepoel, Jared G. Galloway, Xiang Ji, Karthik Gangavarapu, Marc A. Suchard, Frederick A. Matsen IV

Gradients of probabilistic model likelihoods with respect to their parameters are essential for modern computational statistics and machine learning.

Variational Inference

Scalable Bayesian divergence time estimation with ratio transformations

1 code implementation25 Oct 2021 Xiang Ji, Alexander A. Fisher, Shuo Su, Jeffrey L. Thorne, Barney Potter, Philippe Lemey, Guy Baele, Marc A. Suchard

Divergence time estimation is crucial to provide temporal signals for dating biologically important events, from species divergence to viral transmissions in space and time.

Principled, practical, flexible, fast: a new approach to phylogenetic factor analysis

2 code implementations2 Jul 2021 Gabriel W. Hassler, Brigida Gallone, Leandro Aristide, William L. Allen, Max R. Tolkoff, Andrew J. Holbrook, Guy Baele, Philippe Lemey, Marc A. Suchard

Even in the presence of non-trivial phylogenetic model constraints, we show that one may analytically address latent factor uncertainty in a way that (a) aids model flexibility, (b) accelerates computation (by as much as 500-fold) and (c) decreases required tuning.

Combining Cox Regressions Across a Heterogeneous Distributed Research Network Facing Small and Zero Counts

no code implementations5 Jan 2021 Martijn J. Schuemie, Yong Chen, David Madigan, Marc A. Suchard

Studies of the effects of medical interventions increasingly take place in distributed research settings using data from multiple clinical data sources including electronic health records and administrative claims.

Methodology

Shrinkage with shrunken shoulders: Gibbs sampling shrinkage model posteriors with guaranteed convergence rates

2 code implementations6 Nov 2019 Akihiko Nishimura, Marc A. Suchard

Use of continuous shrinkage priors -- with a "spike" near zero and heavy-tails towards infinity -- is an increasingly popular approach to induce sparsity in parameter estimates.

Methodology Statistics Theory Statistics Theory

Gradients do grow on trees: a linear-time ${\cal O}\hspace{-0.2em}\left( N \right)$-dimensional gradient for statistical phylogenetics

1 code implementation29 May 2019 Xiang Ji, Zhen-Yu Zhang, Andrew Holbrook, Akihiko Nishimura, Guy Baele, Andrew Rambaut, Philippe Lemey, Marc A. Suchard

To make this tractable, we present a linear-time algorithm for ${\cal O}\hspace{-0. 2em}\left( N \right)$-dimensional gradient evaluation and apply it to general continuous-time Markov processes of sequence substitution on a phylogenetic tree without a need to assume either stationarity or reversibility.

Computation Populations and Evolution Methodology

Prior-preconditioned conjugate gradient method for accelerated Gibbs sampling in "large $n$ & large $p$" Bayesian sparse regression

1 code implementation29 Oct 2018 Akihiko Nishimura, Marc A. Suchard

We can then solve the linear system by the conjugate gradient (CG) algorithm through matrix-vector multiplications by $\Phi$; this involves no explicit factorization or calculation of $\Phi$ itself.

Spatio-temporal Dynamics of Foot-and-Mouth Disease Virus in South America

1 code implementation5 May 2015 Luiz Max Carvalho, Nuno Rodrigues Faria, Andres M. Perez, Marc A. Suchard, Philippe Lemey, Waldemir de Castro Silveira, Andrew Rambaut, Guy Baele

Although foot-and-mouth disease virus (FMDV) incidence has decreased in South America over the last years, the pathogen still circulates in the region and the risk of re-emergence in previously FMDV-free areas is a veterinary public health concern.

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