1 #ifndef STAN_MATH_REV_SCAL_FUN_LOG_MIX_HPP
2 #define STAN_MATH_REV_SCAL_FUN_LOG_MIX_HPP
29 const double& lambda1_val,
30 const double& lambda2_val,
31 double& one_m_exp_lam2_m_lam1,
32 double& one_m_t_prod_exp_lam2_m_lam1,
33 double& one_d_t_plus_one_m_t_prod_exp_lam2_m_lam1) {
35 double lam2_m_lam1 = lambda2_val - lambda1_val;
36 double exp_lam2_m_lam1 =
exp(lam2_m_lam1);
37 one_m_exp_lam2_m_lam1 = 1 - exp_lam2_m_lam1;
38 double one_m_t = 1 - theta_val;
39 one_m_t_prod_exp_lam2_m_lam1 = one_m_t * exp_lam2_m_lam1;
40 one_d_t_plus_one_m_t_prod_exp_lam2_m_lam1
41 = 1 / (theta_val + one_m_t_prod_exp_lam2_m_lam1);
83 template <
typename T_theta,
89 const T_lambda1& lambda1,
90 const T_lambda2& lambda2) {
97 operands_and_partials(theta, lambda1, lambda2);
99 double theta_double =
value_of(theta);
100 const double lambda1_double =
value_of(lambda1);
101 const double lambda2_double =
value_of(lambda2);
103 double log_mix_function_value
104 =
log_mix(theta_double, lambda1_double, lambda2_double);
106 double one_m_exp_lam2_m_lam1(0.0);
107 double one_m_t_prod_exp_lam2_m_lam1(0.0);
108 double one_d_t_plus_one_m_t_prod_exp_lam2_m_lam1(0.0);
110 if (lambda1 > lambda2) {
114 one_m_exp_lam2_m_lam1,
115 one_m_t_prod_exp_lam2_m_lam1,
116 one_d_t_plus_one_m_t_prod_exp_lam2_m_lam1);
121 one_m_exp_lam2_m_lam1,
122 one_m_t_prod_exp_lam2_m_lam1,
123 one_d_t_plus_one_m_t_prod_exp_lam2_m_lam1);
124 one_m_exp_lam2_m_lam1 = -one_m_exp_lam2_m_lam1;
125 theta_double = one_m_t_prod_exp_lam2_m_lam1;
126 one_m_t_prod_exp_lam2_m_lam1 = 1.0 -
value_of(theta);
130 operands_and_partials.
d_x1[0]
131 = one_m_exp_lam2_m_lam1
132 * one_d_t_plus_one_m_t_prod_exp_lam2_m_lam1;
134 operands_and_partials.
d_x2[0]
136 * one_d_t_plus_one_m_t_prod_exp_lam2_m_lam1;
138 operands_and_partials.
d_x3[0]
139 = one_m_t_prod_exp_lam2_m_lam1
140 * one_d_t_plus_one_m_t_prod_exp_lam2_m_lam1;
142 return operands_and_partials.
value(log_mix_function_value);
VectorView< T_return_type, false, true > d_x2
T value_of(const fvar< T > &v)
Return the value of the specified variable.
fvar< T > log(const fvar< T > &x)
T_return_type value(double value)
Returns a T_return_type with the value specified with the partial derivatves.
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
Metaprogram to determine if a type has a base scalar type that can be assigned to type double...
fvar< T > exp(const fvar< T > &x)
This class builds partial derivatives with respect to a set of operands.
VectorView< T_return_type, false, true > d_x3
void log_mix_partial_helper(const T_theta &theta, const T_lambda1 &lambda1, const T_lambda2 &lambda2, typename boost::math::tools::promote_args< T_theta, T_lambda1, T_lambda2 >::type(&partials_array)[N])
fvar< T > log_mix(const fvar< T > &theta, const fvar< T > &lambda1, const fvar< T > &lambda2)
Return the log mixture density with specified mixing proportion and log densities and its derivative ...
fvar< T > log1m(const fvar< T > &x)
VectorView< T_return_type, false, true > d_x1