Simulation length

However, in many applications the essential space cannot be reduced to only one degree of freedom, and the statistics of the force fluctuation or of the spatial distribution may appear to be too poor to allow for an accurate determination of a multidimensional potential of mean force. An example is the potential of mean force between two ions in aqueous solution the momentaneous forces are two orders of magnitude larger than their average which means that an error of 1% in the average requires a simulation length of 10 times the correlation time of the fluctuating force. This is in practice prohibitive. The errors do not result from incorrect force fields, but they are of a statistical nature even an exact force field would not suffice. 

For an ergodic system, if the simulation length n —> oo, then du(n) —> 0. By analogy with molecular dynamics, for large n we expect the form of the convergence to be [5]... 

Mutations Force Field NB Simulation Length. .f. calc AG sol (kcal/mol) (kcal/mol) Ref. 

It must be borne in mind, however, that the typical simulation lengths that can be achieved with modem hardware and software are very, very rarely in excess of 1 ps. It is thus quite possible that the simulation, although it appears to be converged with respect to the analyses noted above, is trapped in a metastable state having a lifetime in excess of 1 ps, and as a... 

To understand the nanoscale features of many polymer-based materials, then, one needs a new class of theoretical methods—something between the traditional atomistic/molecular simulations (length scales of... 

In the drive to optimize use of available hardware to enable more robust simulations through increasing system size and simulation length, the optimization of MD algorithms for vector hardware has been extensively discussed in the literature, -203 vv ith considerable attention paid to the task of optimizing efficiency.204,20J provide some background to this effort because much of the work impacts subsequent parallel implementations. 

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