Discreteness Effects in Population Dynamics

Abstract : We analyse numerically the effects of small population size in the initial transient regime of a simple example population dynamics. These effects play an important role for the numerical determination of large deviation functions of additive observables for stochastic processes. A method commonly used in order to determine such functions is the so-called cloning algorithm which in its non-constant population version essentially reduces to the determination of the growth rate of a population, averaged over many realizations of the dynamics. However, the averaging of populations is highly dependent not only on the number of realizations of the population dynamics, and on the initial population size but also on the cut-off time (or population) considered to stop their numerical evolution. This may result in an over-influence of discreteness effects at initial times, caused by small population size. We overcome these effects by introducing a (realization-dependent) time delay in the evolution of populations, additional to the discarding of the initial transient regime of the population growth where these discreteness effects are strong. We show that the improvement in the estimation of the large deviation function comes precisely from these two main contributions.
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https://hal.archives-ouvertes.fr/hal-01262593
Contributeur : Vivien Lecomte <>
Soumis le : mardi 26 janvier 2016 - 18:50:35
Dernière modification le : mardi 11 octobre 2016 - 15:20:13

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  • HAL Id : hal-01262593, version 1
  • ARXIV : 1512.01495

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UPMC | IJM | PMA | USPC

Citation

Esteban Guevara Hidalgo, Vivien Lecomte. Discreteness Effects in Population Dynamics. 2015. <hal-01262593>

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