multinomial_logit_lpmf() [1/2]

template<bool propto, typename T_beta , typename T_prob = scalar_type_t<T_beta>, require_eigen_col_vector_t< T_beta > * = nullptr>

return_type_t< T_prob > stan::math::multinomial_logit_lpmf ( const std::vector< int > &  ns, const T_beta &  beta  )

inline

Multinomial log PMF in log parametrization.

Multinomial(ns| softmax(beta))

Entries of beta equal to -inf have zero probability; if any entries are +inf, probability is split evenly among them. These are the limits of softmax: as beta[n] -> -inf, softmax(beta)[n] -> 0, and if k entries -> +inf at the same rate, each has probability 1/k.

Parameters

ns	Array of outcome counts
beta	Vector of unnormalized log probabilities

Returns

log probability

Exceptions

std::invalid_argument	if the sizes of ns and beta do not match
std::domain_error	if any element of ns is negative
std::domain_error	if beta contains NaN
std::domain_error	if beta is non-empty and every entry of beta is negative infinity
std::domain_error	if beta is an autodiff (var) type and contains any non-finite value

Definition at line 39 of file multinomial_logit_lpmf.hpp.