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uniform_log.hpp
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1 #ifndef STAN_MATH_PRIM_SCAL_PROB_UNIFORM_LOG_HPP
2 #define STAN_MATH_PRIM_SCAL_PROB_UNIFORM_LOG_HPP
3
4 #include <boost/random/uniform_real_distribution.hpp>
5 #include <boost/random/variate_generator.hpp>
6 #include <stan/math/prim/scal/meta/OperandsAndPartials.hpp>
7 #include <stan/math/prim/scal/err/check_consistent_sizes.hpp>
8 #include <stan/math/prim/scal/err/check_finite.hpp>
9 #include <stan/math/prim/scal/err/check_greater.hpp>
10 #include <stan/math/prim/scal/err/check_not_nan.hpp>
11 #include <stan/math/prim/scal/fun/constants.hpp>
12 #include <stan/math/prim/scal/fun/value_of.hpp>
13 #include <stan/math/prim/scal/meta/VectorBuilder.hpp>
14 #include <stan/math/prim/scal/meta/include_summand.hpp>
15 #include <cmath>
16
17 namespace stan {
18
19 namespace math {
20
21 // CONTINUOUS, UNIVARIATE DENSITIES
43 template <bool propto,
44 typename T_y, typename T_low, typename T_high>
45 typename return_type<T_y, T_low, T_high>::type
46 uniform_log(const T_y& y, const T_low& alpha, const T_high& beta) {
47 static const char* function("stan::math::uniform_log");
48 typedef typename stan::partials_return_type<T_y, T_low, T_high>::type
49 T_partials_return;
50
51 using stan::math::check_not_nan;
52 using stan::math::check_finite;
53 using stan::math::check_greater;
54 using stan::math::value_of;
55 using stan::math::check_consistent_sizes;
56 using std::log;
57
58 // check if any vectors are zero length
59 if (!(stan::length(y)
60 && stan::length(alpha)
61 && stan::length(beta)))
62 return 0.0;
63
64 // set up return value accumulator
65 T_partials_return logp(0.0);
66 check_not_nan(function, "Random variable", y);
67 check_finite(function, "Lower bound parameter", alpha);
68 check_finite(function, "Upper bound parameter", beta);
69 check_greater(function, "Upper bound parameter", beta, alpha);
70 check_consistent_sizes(function,
71 "Random variable", y,
72 "Lower bound parameter", alpha,
73 "Upper bound parameter", beta);
74
75 // check if no variables are involved and prop-to
76 if (!include_summand<propto, T_y, T_low, T_high>::value)
77 return 0.0;
78
79 VectorView<const T_y> y_vec(y);
80 VectorView<const T_low> alpha_vec(alpha);
81 VectorView<const T_high> beta_vec(beta);
82 size_t N = max_size(y, alpha, beta);
83
84 for (size_t n = 0; n < N; n++) {
85 const T_partials_return y_dbl = value_of(y_vec[n]);
86 if (y_dbl < value_of(alpha_vec[n])
87 || y_dbl > value_of(beta_vec[n]))
88 return LOG_ZERO;
89 }
90
91 VectorBuilder<include_summand<propto, T_low, T_high>::value,
92 T_partials_return, T_low, T_high>
93 inv_beta_minus_alpha(max_size(alpha, beta));
94 for (size_t i = 0; i < max_size(alpha, beta); i++)
95 if (include_summand<propto, T_low, T_high>::value)
96 inv_beta_minus_alpha[i]
97 = 1.0 / (value_of(beta_vec[i]) - value_of(alpha_vec[i]));
98
99 VectorBuilder<include_summand<propto, T_low, T_high>::value,
100 T_partials_return, T_low, T_high>
101 log_beta_minus_alpha(max_size(alpha, beta));
102 for (size_t i = 0; i < max_size(alpha, beta); i++)
103 if (include_summand<propto, T_low, T_high>::value)
104 log_beta_minus_alpha[i]
105 = log(value_of(beta_vec[i]) - value_of(alpha_vec[i]));
106
107 OperandsAndPartials<T_y, T_low, T_high>
108 operands_and_partials(y, alpha, beta);
109 for (size_t n = 0; n < N; n++) {
110 if (include_summand<propto, T_low, T_high>::value)
111 logp -= log_beta_minus_alpha[n];
112
113 if (!is_constant_struct<T_low>::value)
114 operands_and_partials.d_x2[n] += inv_beta_minus_alpha[n];
115 if (!is_constant_struct<T_high>::value)
116 operands_and_partials.d_x3[n] -= inv_beta_minus_alpha[n];
117 }
118 return operands_and_partials.to_var(logp, y, alpha, beta);
119 }
120
121 template <typename T_y, typename T_low, typename T_high>
122 inline
123 typename return_type<T_y, T_low, T_high>::type
124 uniform_log(const T_y& y, const T_low& alpha, const T_high& beta) {
125 return uniform_log<false>(y, alpha, beta);
126 }
127 }
128 }
129 #endif
check_not_nan.hpp
stan::math::check_not_nan
bool check_not_nan(const char *function, const char *name, const T_y &y)
Return true if y is not NaN.
Definition: check_not_nan.hpp:63
stan::math::value_of
T value_of(const fvar< T > &v)
Return the value of the specified variable.
Definition: value_of.hpp:16
stan::math::log
fvar< T > log(const fvar< T > &x)
Definition: log.hpp:15
stan::length
size_t length(const std::vector< T > &x)
Definition: length.hpp:10
stan::math::OperandsAndPartials::to_var
T_return_type to_var(T_partials_return logp, const T1 &x1=0, const T2 &x2=0, const T3 &x3=0, const T4 &x4=0, const T5 &x5=0, const T6 &x6=0)
Definition: OperandsAndPartials.hpp:322
stan::math::LOG_ZERO
const double LOG_ZERO
Definition: constants.hpp:175
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
stan::return_type::type
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
include_summand.hpp
check_greater.hpp
stan::is_constant_struct
Metaprogram to determine if a type has a base scalar type that can be assigned to type double...
Definition: is_constant_struct.hpp:16
stan::math::OperandsAndPartials::d_x3
VectorView< T_partials_return, is_vector< T3 >::value, is_constant_struct< T3 >::value > d_x3
Definition: OperandsAndPartials.hpp:259
stan::math::OperandsAndPartials
A variable implementation that stores operands and derivatives with respect to the variable...
Definition: OperandsAndPartials.hpp:238
OperandsAndPartials.hpp
stan::max_size
size_t max_size(const T1 &x1, const T2 &x2)
Definition: max_size.hpp:9
VectorBuilder.hpp
stan::math::check_finite
bool check_finite(const char *function, const char *name, const T_y &y)
Return true if y is finite.
Definition: check_finite.hpp:62
stan::VectorBuilder
Definition: VectorBuilder.hpp:61
constants.hpp
stan::math::check_consistent_sizes
bool check_consistent_sizes(const char *function, const char *name1, const T1 &x1, const char *name2, const T2 &x2)
Return true if the dimension of x1 is consistent with x2.
Definition: check_consistent_sizes.hpp:31
check_finite.hpp
stan::math::uniform_log
return_type< T_y, T_low, T_high >::type uniform_log(const T_y &y, const T_low &alpha, const T_high &beta)
The log of a uniform density for the given y, lower, and upper bound.
Definition: uniform_log.hpp:46
stan::math::OperandsAndPartials::d_x2
VectorView< T_partials_return, is_vector< T2 >::value, is_constant_struct< T2 >::value > d_x2
Definition: OperandsAndPartials.hpp:256
value_of.hpp
stan::VectorView
VectorView is a template metaprogram that takes its argument and allows it to be used like a vector...
Definition: VectorView.hpp:41
stan::partials_return_type::type
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
Definition: partials_return_type.hpp:26
check_consistent_sizes.hpp
stan::math::check_greater
bool check_greater(const char *function, const char *name, const T_y &y, const T_low &low)
Return true if y is strictly greater than low.
Definition: check_greater.hpp:84

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