Parameter Hopping. Implementation
Monte Carlo simulation in which l-change trials are attempted
Accept trials as usual, with probability min[1,e-bDU]
Record fractions f0, f1 of configurations spent in l = l0 and l = l1
Free energy is given by ratio
In practice, system may spend almost no time in one of the values
- Can apply weighting function w(l) to encourage it to sample both
- Accept trials with probability min[1,(wn/wo) e-bDU]
- Free energy is
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- Good choice for w has f1 = f0
Multivalue extension is particularly effective
- l takes on a continuum of values