Random local clock – rate prior

Since the rate parameter has different meaning for different settings of the scaling and ratesAreMultipliers settings, there are different strategies for determining the prior.

If scaling=true, the rate prior should have a mean of 1, and is scaling=false, the rate prior should have a mean of the expected clock rate – see clock prior for details.

Be aware that the variance of the prior should be rather small if ratesAreMultipliers=true, and can be larger when ratesAreMultipliers=false.

Since these are rates, they are positive values and a distribution with a positive range should be used, e.g. one of the log-normal, gamma, inverse gamma, Weibel distributions.