Families and links#
Response families define the variance function and the weight semantics;
links map the linear predictor to the mean.
estimate_theta() and
estimate_p() estimate the extra parameter those
families carry and return the profile results listed here.
Convenience constructors for distribution families. |
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Poisson distribution. |
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Gaussian distribution. |
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Gamma distribution. |
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Binomial (Bernoulli) distribution. |
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Negative binomial (NB2) family with overdispersion controlled by |
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Tweedie distribution. |
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Log link: eta = log(mu), mu = exp(eta). |
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Logit link: eta = log(mu / (1-mu)), mu = expit(eta). |
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Identity link: eta = mu, mu = eta. |
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Probit link: eta = Phi^{-1}(mu), mu = Phi(eta). |
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Complementary log-log link: eta = log(-log(1 - mu)). |
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Cauchit link: eta = tan(pi*(mu - 0.5)), mu = 0.5 + arctan(eta)/pi. |
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Inverse (reciprocal) link: eta = 1/mu, mu = 1/eta. |
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Inverse-squared link: eta = 1/mu^2, mu = 1/sqrt(eta). |
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Square-root link: eta = sqrt(mu), mu = eta^2. |
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Power link: eta = mu^p, mu = eta^(1/p). |
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Negative binomial link: eta = log(mu / (mu + theta)). |
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Profile-likelihood estimate of the NB2 shape theta. |
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Profile-likelihood estimate of the Tweedie power p and dispersion phi. |
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Row log densities of Tweedie(mu, phi / w, p), 1 < p < 2 (Dunn & Smyth 2005). |
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Simulate Tweedie(mu, phi, p) as compound Poisson-gamma: N ~ Poisson, Y | N ~ Gamma. |