Split Hamiltonian Monte Carlo

Babak Shahbaba, Shiwei Lan, Wesley O. Johnson, Radford M. Neal

Research output: Contribution to journalArticlepeer-review

34 Scopus citations


We show how the Hamiltonian Monte Carlo algorithm can sometimes be speeded up by "splitting" the Hamiltonian in a way that allows much of the movement around the state space to be done at low computational cost. One context where this is possible is when the log density of the distribution of interest (the potential energy function) can be written as the log of a Gaussian density, which is a quadratic function, plus a slowly-varying function. Hamiltonian dynamics for quadratic energy functions can be analytically solved. With the splitting technique, only the slowly-varying part of the energy needs to be handled numerically, and this can be done with a larger stepsize (and hence fewer steps) than would be necessary with a direct simulation of the dynamics. Another context where splitting helps is when the most important terms of the potential energy function and its gradient can be evaluated quickly, with only a slowly-varying part requiring costly computations. With splitting, the quick portion can be handled with a small stepsize, while the costly portion uses a larger stepsize. We show that both of these splitting approaches can reduce the computational cost of sampling from the posterior distribution for a logistic regression model, using either a Gaussian approximation centered on the posterior mode, or a Hamiltonian split into a term that depends on only a small number of critical cases, and another term that involves the larger number of cases whose influence on the posterior distribution is small.

Original languageEnglish (US)
Pages (from-to)339-349
Number of pages11
JournalStatistics and Computing
Issue number3
StatePublished - May 2014
Externally publishedYes


  • Bayesian analysis
  • Hamiltonian dynamics
  • Markov chain Monte Carlo

ASJC Scopus subject areas

  • Theoretical Computer Science
  • Statistics and Probability
  • Statistics, Probability and Uncertainty
  • Computational Theory and Mathematics


Dive into the research topics of 'Split Hamiltonian Monte Carlo'. Together they form a unique fingerprint.

Cite this