class TransitionMatrix : public feasst::Bias

Transition matrix flat histogram bias.

Direct calculation of liquid–vapor phase equilibria from transition matrix Monte Carlo simulation

Elucidating the effects of adsorbent flexibility on fluid adsorption using simple models and flat-histogram sampling methods.

A count of all accepted transitions between macrostates is used for a newly developed sweep metric.

Note that transitions to macrostates that have not yet been sampled are unbiased. This can lead to long initialization times, depending on your choice of the chemical potential. For example, if a simulation begins with zero particles and attempts a particle insertion, this insertion is unlikely to be accepted if the chemical potential is very low (favoring less particles). This can lead to very low initialization times. This issue can be overcome with the use of WLTM, which instead uses Wang-Landau to initialize the transition matrix. This makes WLTM less sensitive than TM to the choice of chemical potential in terms of efficiency.


  • CollectionMatrix arguments.

  • min_visits: A sweep is performed when all macrostates are visited by another macrostate this number of times (default: 100).

  • average_visits: A sweep is performed when macrostates are visited by another macrostate more than this average number of times (default: 0).

  • min_sweeps: Number of sweeps required for completion.

  • reset_sweeps: The ‘phase’ counter increments from 0 to 1 when reset_sweeps are completed (default: -1 [counter will never increment])

  • new_sweep: if set to 1, use new sweep definition of “the minimum number

    of accepted transitions for each possible” (default: 0).

  • widom: if true, also store a CollectionMatrix without the minimum(1,P) term typical of Metropolis acceptance (default: false). This allows direct calculation of the chemical potential