Monte Carlo Methodsvagelis/Courses/EM385/MC_Ch4_Markov-Chains-… · MC Methods, Ch. 4: Markovian...

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Monte Carlo Methods Part IV: Markov Chains Monte Carlo Spring Semester 2013/14, Department of Applied Mathematics, University of Crete Instructor: Harmandaris Vagelis, email: [email protected]

Transcript of Monte Carlo Methodsvagelis/Courses/EM385/MC_Ch4_Markov-Chains-… · MC Methods, Ch. 4: Markovian...

Page 1: Monte Carlo Methodsvagelis/Courses/EM385/MC_Ch4_Markov-Chains-… · MC Methods, Ch. 4: Markovian Chains GeneralComments: Gibbs Sampler One special case of Metropolis-Hastings is

Monte Carlo Methods

Part IV: Markov Chains Monte Carlo

Spring Semester 2013/14, Department of Applied Mathematics, University of Crete

Instructor: Harmandaris Vagelis, email: [email protected]

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MC Methods, Ch. 4: Markovian Chains

Basic Definitions:

Markov Chains

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MC Methods, Ch. 4: Markovian Chains

Essentials of Markov Chains Monte Carlo (MCMC) algorithms:

Markov Chains

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MC Methods, Ch. 4: Markovian Chains

Markov Chains

Essentials of Markov Chains Monte Carlo (MCMC) algorithms:

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MC Methods, Ch. 4: Markovian Chains

The MCMC principle:

Metropolis – Hastings Algorithm

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MC Methods, Ch. 4: Markovian Chains

Metropolis – Hastings Algorithm

Requirements:

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MC Methods, Ch. 4: Markovian Chains

Metropolis – Hastings Algorithm

The Algorithm:

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MC Methods, Ch. 4: Markovian Chains

Properties:

Metropolis – Hastings Algorithm

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MC Methods, Ch. 4: Markovian Chains

Random Walk Metropolis

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MC Methods, Ch. 4: Markovian Chains

Random Walk Metropolis

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MC Methods, Ch. 4: Markovian Chains

Random Walk Metropolis

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MC Methods, Ch. 4: Markovian Chains

Histograms - Estimators:

Random Walk Metropolis

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MC Methods, Ch. 4: Markovian Chains

Basic Idea:

Gibbs Sampler

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MC Methods, Ch. 4: Markovian Chains

Random Gibbs Sampler:

Gibbs Sampler

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MC Methods, Ch. 4: Markovian Chains

Important Aspects:

Gibbs Sampler

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MC Methods, Ch. 4: Markovian Chains

General Comments:

Gibbs Sampler

One special case of Metropolis-Hastings is very popular and does not require any choice of step size.

Gibbs sampling is the composition of a sequence of M-H transition operators, each of which acts upon a single component of the state space.

By themselves, these operators are not ergodic, but in aggregate they typically are.

Most commonly, the proposal distribution is taken to be the conditional distribution, given the rest of the state. This causes the acceptance ratio to always be one and is often easy because it is low-dimensional.

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MC Methods, Ch. 4: Markovian Chains

Monte Carlo Strategies in Scientific Computing, J. Liu, Springer, New York, 2001.

Monte Carlo Statistical Methods, C. Robert, G. Casella, Springer, New York,

2004.

Stochastic Methods: A Handbook for the Natural and Social Sciences, C.

Gardiner, Springer, New York, 2009.

Bibliography