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Set values related to the prior distributions for the Bayesian Mallows model.

Usage

set_priors(gamma = 1, lambda = 0.001, psi = 10, kappa = c(1, 3))

Arguments

gamma

Strictly positive numeric value specifying the shape parameter of the gamma prior distribution of \(\alpha\). Defaults to 1, thus recovering the exponential prior distribution used by (Vitelli et al. 2018) .

lambda

Strictly positive numeric value specifying the rate parameter of the gamma prior distribution of \(\alpha\). Defaults to 0.001. When n_cluster > 1, each mixture component \(\alpha_{c}\) has the same prior distribution.

psi

Positive integer specifying the concentration parameter \(\psi\) of the Dirichlet prior distribution used for the cluster probabilities \(\tau_{1}, \tau_{2}, \dots, \tau_{C}\), where \(C\) is the value of n_clusters. Defaults to 10L. When n_clusters = 1, this argument is not used.

kappa

Hyperparameters of the truncated Beta prior used for error probability \(\theta\) in the Bernoulli error model. The prior has the form \(\pi(\theta) = \theta^{\kappa_{1}} (1 - \theta)^{\kappa_{2}}\). Defaults to c(1, 3), which means that the \(\theta\) is a priori expected to be closer to zero than to 0.5. See (Crispino et al. 2019) for details.

Value

An object of class "BayesMallowsPriors", to be provided in the priors argument to compute_mallows(), compute_mallows_mixtures(), or update_mallows().

References

Crispino M, Arjas E, Vitelli V, Barrett N, Frigessi A (2019). “A Bayesian Mallows approach to nontransitive pair comparison data: How human are sounds?” The Annals of Applied Statistics, 13(1), 492–519. doi:10.1214/18-aoas1203 .

Vitelli V, Sørensen, Crispino M, Arjas E, Frigessi A (2018). “Probabilistic Preference Learning with the Mallows Rank Model.” Journal of Machine Learning Research, 18(1), 1–49. https://jmlr.org/papers/v18/15-481.html.