Chapter 3 Markov Chain Monte Carlo: Metropolis and Glauber Chains Yael Harel
Contents • Reminders from previous weeks • Definitions • Theorems • Motivation • Metropolis Chains • What is it? • Construction over symmetric matrices • Example • Construction over asymmetric matrices • Example • Glauber Dynamics • What is it? • Examples • Metropolis Chains VS Glauber Dynamics • Summary
Reminders from previous weeks
Reminders from previous weeks
Motivation e asy d ult c i iff
Metropolis Chains
Metropolis Chains
Metropolis Chains
Metropolis Chains
Glauber Dynamics (Gibbes sampler)
Glauber Dynamics (Gibbes sampler) 0 0
Glauber Dynamics (Gibbes sampler) v is vacant If x(v)=1 y=x
Metropolis Chains VS Glauber Dynamics
Metropolis Chains VS Glauber Dynamics
Metropolis Chains VS Glauber Dynamics
Summary Chain construction with a given stationary distribution • Metropolis – given a transition matrix. • Glauber – without any transition matrix. Can be equal or similar Example – q-coloring • NP-complete problem #proper configurations – unknown. • Construct a chain with the uniform stationary distribution. • Simulation: • For i=1 to N • Run the chain T iterations • Save the result • Learn how does the configurations distribute In the next weeks: How to find T?