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multinomial_log.hpp
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1 #ifndef STAN_MATH_PRIM_MAT_PROB_MULTINOMIAL_LOG_HPP
2 #define STAN_MATH_PRIM_MAT_PROB_MULTINOMIAL_LOG_HPP
3
4 #include <boost/math/special_functions/gamma.hpp>
5 #include <boost/random/uniform_01.hpp>
6 #include <boost/random/variate_generator.hpp>
7 #include <stan/math/prim/mat/err/check_simplex.hpp>
8 #include <stan/math/prim/scal/err/check_size_match.hpp>
9 #include <stan/math/prim/scal/err/check_nonnegative.hpp>
10 #include <stan/math/prim/scal/err/check_positive.hpp>
11 #include <stan/math/prim/scal/fun/multiply_log.hpp>
12 #include <stan/math/prim/scal/fun/constants.hpp>
13 #include <stan/math/prim/scal/meta/include_summand.hpp>
14 #include <vector>
15
16 namespace stan {
17
18 namespace math {
19 // Multinomial(ns|N, theta) [0 <= n <= N; SUM ns = N;
20 // 0 <= theta[n] <= 1; SUM theta = 1]
21 template <bool propto,
22 typename T_prob>
23 typename boost::math::tools::promote_args<T_prob>::type
24 multinomial_log(const std::vector<int>& ns,
25 const Eigen::Matrix<T_prob, Eigen::Dynamic, 1>& theta) {
26 static const char* function("stan::math::multinomial_log");
27
28 using stan::math::check_nonnegative;
29 using stan::math::check_simplex;
30 using stan::math::check_size_match;
31 using boost::math::tools::promote_args;
32 using boost::math::lgamma;
33
34 typename promote_args<T_prob>::type lp(0.0);
35 check_nonnegative(function, "Number of trials variable", ns);
36 check_simplex(function, "Probabilites parameter", theta);
37 check_size_match(function,
38 "Size of number of trials variable", ns.size(),
39 "rows of probabilities parameter", theta.rows());
40 using stan::math::multiply_log;
41
42 if (include_summand<propto>::value) {
43 double sum = 1.0;
44 for (unsigned int i = 0; i < ns.size(); ++i)
45 sum += ns[i];
46 lp += lgamma(sum);
47 for (unsigned int i = 0; i < ns.size(); ++i)
48 lp -= lgamma(ns[i] + 1.0);
49 }
50 if (include_summand<propto, T_prob>::value) {
51 for (unsigned int i = 0; i < ns.size(); ++i)
52 lp += multiply_log(ns[i], theta[i]);
53 }
54 return lp;
55 }
56
57 template <typename T_prob>
58 typename boost::math::tools::promote_args<T_prob>::type
59 multinomial_log(const std::vector<int>& ns,
60 const Eigen::Matrix<T_prob, Eigen::Dynamic, 1>& theta) {
61 return multinomial_log<false>(ns, theta);
62 }
63
64 }
65 }
66 #endif
stan::math::sum
fvar< T > sum(const std::vector< fvar< T > > &m)
Return the sum of the entries of the specified standard vector.
Definition: sum.hpp:20
check_simplex.hpp
stan::math::lgamma
fvar< T > lgamma(const fvar< T > &x)
Definition: lgamma.hpp:15
check_size_match.hpp
check_positive.hpp
stan
Definition: log_sum_exp.hpp:8
stan::math::include_summand
Template metaprogram to calculate whether a summand needs to be included in a proportional (log) prob...
Definition: include_summand.hpp:36
include_summand.hpp
multiply_log.hpp
check_nonnegative.hpp
stan::math::check_size_match
bool check_size_match(const char *function, const char *name_i, T_size1 i, const char *name_j, T_size2 j)
Return true if the provided sizes match.
Definition: check_size_match.hpp:30
stan::math::multiply_log
fvar< T > multiply_log(const fvar< T > &x1, const fvar< T > &x2)
Definition: multiply_log.hpp:15
constants.hpp
stan::math::check_simplex
bool check_simplex(const char *function, const char *name, const Eigen::Matrix< T_prob, Eigen::Dynamic, 1 > &theta)
Return true if the specified vector is simplex.
Definition: check_simplex.hpp:41
stan::math::multinomial_log
boost::math::tools::promote_args< T_prob >::type multinomial_log(const std::vector< int > &ns, const Eigen::Matrix< T_prob, Eigen::Dynamic, 1 > &theta)
Definition: multinomial_log.hpp:24
stan::math::check_nonnegative
bool check_nonnegative(const char *function, const char *name, const T_y &y)
Return true if y is non-negative.
Definition: check_nonnegative.hpp:66

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