title: Convective Replica-Exchange in Ergodic Regimes.
abstract: In a recent article (J. Comput. Chem. 2013, 34, 132-140), convective replica-exchange (convective-RE) has been presented as an alternative to the standard even-odd transition scheme. Computations on systems of various complexity have shown that convective-RE may increase the number of replica round-trips in temperature space with respect to the standard exchange scheme, leading to a more effective sampling of energy basins. Moreover, it has been shown that the method may prevent the formation of bottlenecks in the diffusive walk of replicas through the space of temperature states. By using an ideal temperature-RE model and a classical harmonic-oscillator RE scheme, we study the performances of convective-RE when ergodicity is not broken and convergence of acceptance probabilities is attained. In this dynamic regime, the round-trip ratio between convective and standard-RE is at maximum ∼ 1.5, a value much smaller than that observed in nonergodic simulations. For large acceptance probabilities, the standard-RE outperforms convective-RE. Our observations suggest that convective-RE can safely be used in either ergodic or non-ergodic regimes; however, convective-RE is advantageous only when bottlenecks occur in the state-space diffusion of replicas, or when acceptance probabilities are globally low. We also show that decoupling of the state-space dynamics of the stick replica from the dynamics of the remaining replicas improves the efficiency of convective-RE at low acceptance probability regimes.
authors.affiliation: Dipartimento di Chimica, Università di Firenze , Via della Lastruccia 3, I-50019 Sesto Fiorentino, Italy.
authors.forename: Giorgio F
authors.initials: GF
authors.lastname: Signorini
authors.affiliation: Dipartimento di Chimica, Università di Firenze , Via della Lastruccia 3, I-50019 Sesto Fiorentino, Italy.
authors.forename: Edoardo
authors.initials: E
authors.lastname: Giovannelli
authors.affiliation: Institut Pasteur , Structural Bioinformatics and Chemistry Department, 25 Rue du Docteur Roux, 75015 Paris, France.
authors.forename: Yannick G
authors.initials: YG
authors.lastname: Spill
authors.affiliation: Institut Pasteur , Structural Bioinformatics and Chemistry Department, 25 Rue du Docteur Roux, 75015 Paris, France.
authors.forename: Michael
authors.initials: M
authors.lastname: Nilges
authors.affiliation: Dipartimento di Chimica, Università di Firenze , Via della Lastruccia 3, I-50019 Sesto Fiorentino, Italy.|European Laboratory for Non-linear Spectroscopy (LENS), Via Nello Carrara 1, I-50019 Sesto Fiorentino, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Chelli