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trace_quad_form.hpp
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1 #ifndef STAN_MATH_REV_MAT_FUN_TRACE_QUAD_FORM_HPP
2 #define STAN_MATH_REV_MAT_FUN_TRACE_QUAD_FORM_HPP
3
4 #include <boost/utility/enable_if.hpp>
5 #include <boost/type_traits.hpp>
6 #include <stan/math/rev/core.hpp>
7 #include <stan/math/prim/mat/fun/Eigen.hpp>
8 #include <stan/math/prim/mat/fun/typedefs.hpp>
9 #include <stan/math/rev/scal/fun/value_of.hpp>
10 #include <stan/math/prim/mat/fun/value_of.hpp>
11 #include <stan/math/rev/mat/fun/typedefs.hpp>
12 #include <stan/math/prim/mat/fun/trace_quad_form.hpp>
13 #include <stan/math/prim/mat/err/check_multiplicable.hpp>
14 #include <stan/math/prim/mat/err/check_square.hpp>
15
16 namespace stan {
17 namespace math {
18 namespace {
19 template <typename TA, int RA, int CA, typename TB, int RB, int CB>
20 class trace_quad_form_vari_alloc : public chainable_alloc {
21 public:
22 trace_quad_form_vari_alloc(const Eigen::Matrix<TA, RA, CA>& A,
23 const Eigen::Matrix<TB, RB, CB>& B)
24 : A_(A), B_(B)
25 { }
26
27 double compute() {
28 using stan::math::value_of;
29 return stan::math::trace_quad_form(value_of(A_),
30 value_of(B_));
31 }
32
33 Eigen::Matrix<TA, RA, CA> A_;
34 Eigen::Matrix<TB, RB, CB> B_;
35 };
36
37 template <typename TA, int RA, int CA, typename TB, int RB, int CB>
38 class trace_quad_form_vari : public vari {
39 protected:
40 static inline void chainA(Eigen::Matrix<double, RA, CA>& A,
41 const Eigen::Matrix<double, RB, CB>& Bd,
42 const double& adjC) {}
43 static inline void chainB(Eigen::Matrix<double, RB, CB>& B,
44 const Eigen::Matrix<double, RA, CA>& Ad,
45 const Eigen::Matrix<double, RB, CB>& Bd,
46 const double& adjC) {}
47
48 static inline void chainA(Eigen::Matrix<var, RA, CA>& A,
49 const Eigen::Matrix<double, RB, CB>& Bd,
50 const double& adjC) {
51 Eigen::Matrix<double, RA, CA> adjA(adjC*Bd*Bd.transpose());
52 for (int j = 0; j < A.cols(); j++)
53 for (int i = 0; i < A.rows(); i++)
54 A(i, j).vi_->adj_ += adjA(i, j);
55 }
56 static inline void chainB(Eigen::Matrix<var, RB, CB>& B,
57 const Eigen::Matrix<double, RA, CA>& Ad,
58 const Eigen::Matrix<double, RB, CB>& Bd,
59 const double& adjC) {
60 Eigen::Matrix<double, RA, CA> adjB(adjC*(Ad + Ad.transpose())*Bd);
61 for (int j = 0; j < B.cols(); j++)
62 for (int i = 0; i < B.rows(); i++)
63 B(i, j).vi_->adj_ += adjB(i, j);
64 }
65
66 inline void chainAB(Eigen::Matrix<TA, RA, CA>& A,
67 Eigen::Matrix<TB, RB, CB>& B,
68 const Eigen::Matrix<double, RA, CA>& Ad,
69 const Eigen::Matrix<double, RB, CB>& Bd,
70 const double& adjC) {
71 chainA(A, Bd, adjC);
72 chainB(B, Ad, Bd, adjC);
73 }
74
75
76 public:
77 explicit
78 trace_quad_form_vari
79 (trace_quad_form_vari_alloc<TA, RA, CA, TB, RB, CB> *impl)
80 : vari(impl->compute()), _impl(impl) { }
81
82 virtual void chain() {
83 using stan::math::value_of;
84 chainAB(_impl->A_, _impl->B_,
85 value_of(_impl->A_), value_of(_impl->B_),
86 adj_);
87 }
88
89 trace_quad_form_vari_alloc<TA, RA, CA, TB, RB, CB> *_impl;
90 };
91 }
92
93 template <typename TA, int RA, int CA, typename TB, int RB, int CB>
94 inline typename
95 boost::enable_if_c< boost::is_same<TA, var>::value ||
96 boost::is_same<TB, var>::value,
97 var >::type
98 trace_quad_form(const Eigen::Matrix<TA, RA, CA>& A,
99 const Eigen::Matrix<TB, RB, CB>& B) {
100 stan::math::check_square("trace_quad_form", "A", A);
101 stan::math::check_multiplicable("trace_quad_form",
102 "A", A,
103 "B", B);
104
105 trace_quad_form_vari_alloc<TA, RA, CA, TB, RB, CB> *baseVari
106 = new trace_quad_form_vari_alloc<TA, RA, CA, TB, RB, CB>(A, B);
107
108 return var(new trace_quad_form_vari<TA, RA, CA, TB, RB, CB>(baseVari));
109 }
110 }
111 }
112
113 #endif
core.hpp
check_multiplicable.hpp
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::var
Independent (input) and dependent (output) variables for gradients.
Definition: var.hpp:32
A_
Eigen::Matrix< TA, RA, CA > A_
Definition: trace_quad_form.hpp:33
stan::math::trace_quad_form
stan::math::fvar< T > trace_quad_form(const Eigen::Matrix< stan::math::fvar< T >, RA, CA > &A, const Eigen::Matrix< stan::math::fvar< T >, RB, CB > &B)
Definition: trace_quad_form.hpp:18
typedefs.hpp
stan::math::check_multiplicable
bool check_multiplicable(const char *function, const char *name1, const T1 &y1, const char *name2, const T2 &y2)
Return true if the matrices can be multiplied.
Definition: check_multiplicable.hpp:33
trace_quad_form.hpp
B_
Eigen::Matrix< TB, RB, CB > B_
Definition: trace_quad_form.hpp:34
Eigen.hpp
_impl
trace_quad_form_vari_alloc< TA, RA, CA, TB, RB, CB > * _impl
Definition: trace_quad_form.hpp:89
value_of.hpp
stan::math::check_square
bool check_square(const char *function, const char *name, const Eigen::Matrix< T_y, Eigen::Dynamic, Eigen::Dynamic > &y)
Return true if the specified matrix is square.
Definition: check_square.hpp:28
value_of.hpp
typedefs.hpp
check_square.hpp

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