Stan Math Library  2.15.0
reverse mode automatic differentiation
binomial_lpmf.hpp
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1 #ifndef STAN_MATH_PRIM_SCAL_PROB_BINOMIAL_LPMF_HPP
2 #define STAN_MATH_PRIM_SCAL_PROB_BINOMIAL_LPMF_HPP
3 
25 #include <boost/random/binomial_distribution.hpp>
26 #include <boost/random/variate_generator.hpp>
27 
28 namespace stan {
29  namespace math {
30 
48  template <bool propto,
49  typename T_n,
50  typename T_N,
51  typename T_prob>
53  binomial_lpmf(const T_n& n,
54  const T_N& N,
55  const T_prob& theta) {
57  T_partials_return;
58 
59  static const char* function("binomial_lpmf");
60 
61  if (!(stan::length(n)
62  && stan::length(N)
63  && stan::length(theta)))
64  return 0.0;
65 
66  T_partials_return logp = 0;
67  check_bounded(function, "Successes variable", n, 0, N);
68  check_nonnegative(function, "Population size parameter", N);
69  check_finite(function, "Probability parameter", theta);
70  check_bounded(function, "Probability parameter", theta, 0.0, 1.0);
71  check_consistent_sizes(function,
72  "Successes variable", n,
73  "Population size parameter", N,
74  "Probability parameter", theta);
75 
77  return 0.0;
78 
81  scalar_seq_view<const T_prob> theta_vec(theta);
82  size_t size = max_size(n, N, theta);
83 
84  OperandsAndPartials<T_prob> operands_and_partials(theta);
85 
87  for (size_t i = 0; i < size; ++i)
88  logp += binomial_coefficient_log(N_vec[i], n_vec[i]);
89  }
90 
92  for (size_t i = 0; i < length(theta); ++i)
93  log1m_theta[i] = log1m(value_of(theta_vec[i]));
94 
95  for (size_t i = 0; i < size; ++i)
96  logp += multiply_log(n_vec[i], value_of(theta_vec[i]))
97  + (N_vec[i] - n_vec[i]) * log1m_theta[i];
98 
99  if (length(theta) == 1) {
100  T_partials_return temp1 = 0;
101  T_partials_return temp2 = 0;
102  for (size_t i = 0; i < size; ++i) {
103  temp1 += n_vec[i];
104  temp2 += N_vec[i] - n_vec[i];
105  }
107  operands_and_partials.d_x1[0]
108  += temp1 / value_of(theta_vec[0])
109  - temp2 / (1.0 - value_of(theta_vec[0]));
110  }
111  } else {
113  for (size_t i = 0; i < size; ++i)
114  operands_and_partials.d_x1[i]
115  += n_vec[i] / value_of(theta_vec[i])
116  - (N_vec[i] - n_vec[i]) / (1.0 - value_of(theta_vec[i]));
117  }
118  }
119 
120  return operands_and_partials.value(logp);
121  }
122 
123  template <typename T_n,
124  typename T_N,
125  typename T_prob>
126  inline
128  binomial_lpmf(const T_n& n,
129  const T_N& N,
130  const T_prob& theta) {
131  return binomial_lpmf<false>(n, N, theta);
132  }
133 
134  }
135 }
136 #endif
void check_finite(const char *function, const char *name, const T_y &y)
Check if y is finite.
fvar< T > binomial_coefficient_log(const fvar< T > &x1, const fvar< T > &x2)
void check_bounded(const char *function, const char *name, const T_y &y, const T_low &low, const T_high &high)
Check if the value is between the low and high values, inclusively.
T value_of(const fvar< T > &v)
Return the value of the specified variable.
Definition: value_of.hpp:16
T_return_type value(double value)
Returns a T_return_type with the value specified with the partial derivatves.
scalar_seq_view provides a uniform sequence-like wrapper around either a scalar or a sequence of scal...
return_type< T_prob >::type binomial_lpmf(const T_n &n, const T_N &N, const T_prob &theta)
Returns the log PMF for the binomial distribution evaluated at the specified success, population size, and chance of success.
size_t length(const std::vector< T > &x)
Definition: length.hpp:10
Template metaprogram to calculate whether a summand needs to be included in a proportional (log) prob...
void check_nonnegative(const char *function, const char *name, const T_y &y)
Check if y is non-negative.
boost::math::tools::promote_args< typename scalar_type< T1 >::type, typename scalar_type< T2 >::type, typename scalar_type< T3 >::type, typename scalar_type< T4 >::type, typename scalar_type< T5 >::type, typename scalar_type< T6 >::type >::type type
Definition: return_type.hpp:27
Metaprogram to determine if a type has a base scalar type that can be assigned to type double...
This class builds partial derivatives with respect to a set of operands.
size_t max_size(const T1 &x1, const T2 &x2)
Definition: max_size.hpp:9
fvar< T > multiply_log(const fvar< T > &x1, const fvar< T > &x2)
VectorBuilder allocates type T1 values to be used as intermediate values.
int size(const std::vector< T > &x)
Return the size of the specified standard vector.
Definition: size.hpp:17
void check_consistent_sizes(const char *function, const char *name1, const T1 &x1, const char *name2, const T2 &x2)
Check if the dimension of x1 is consistent with x2.
boost::math::tools::promote_args< typename partials_type< typename scalar_type< T1 >::type >::type, typename partials_type< typename scalar_type< T2 >::type >::type, typename partials_type< typename scalar_type< T3 >::type >::type, typename partials_type< typename scalar_type< T4 >::type >::type, typename partials_type< typename scalar_type< T5 >::type >::type, typename partials_type< typename scalar_type< T6 >::type >::type >::type type
fvar< T > log1m(const fvar< T > &x)
Definition: log1m.hpp:13
VectorView< T_return_type, false, true > d_x1

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