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sum.hpp
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1 #ifndef STAN_MATH_REV_ARR_FUN_SUM_HPP
2 #define STAN_MATH_REV_ARR_FUN_SUM_HPP
3
4 #include <stan/math/rev/core.hpp>
5 #include <vector>
6
7 namespace stan {
8 namespace math {
9
14 class sum_v_vari : public vari {
15 protected:
16 vari** v_;
17 size_t length_;
18
19 inline static double sum_of_val(const std::vector<var>& v) {
20 double result = 0;
21 for (size_t i = 0; i < v.size(); i++)
22 result += v[i].val();
23 return result;
24 }
25
26 public:
27 explicit sum_v_vari(double value, vari** v, size_t length)
28 : vari(value), v_(v), length_(length) {
29 }
30
31 explicit sum_v_vari(const std::vector<var> &v1)
32 : vari(sum_of_val(v1)),
33 v_(reinterpret_cast<vari**>(ChainableStack::memalloc_
34 .alloc(v1.size() * sizeof(vari*)))),
35 length_(v1.size()) {
36 for (size_t i = 0; i < length_; i++)
37 v_[i] = v1[i].vi_;
38 }
39
40 virtual void chain() {
41 for (size_t i = 0; i < length_; i++) {
42 v_[i]->adj_ += adj_;
43 }
44 }
45 };
46
53 inline var sum(const std::vector<var>& m) {
54 if (m.size() == 0)
55 return 0.0;
56 return var(new sum_v_vari(m));
57 }
58
59 }
60 }
61 #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
stan::math::sum_v_vari::sum_v_vari
sum_v_vari(double value, vari **v, size_t length)
Definition: sum.hpp:27
stan::math::sum_v_vari::v_
vari ** v_
Definition: sum.hpp:16
core.hpp
stan
Definition: log_sum_exp.hpp:8
stan::math::vari
The variable implementation base class.
Definition: vari.hpp:30
stan::length
size_t length(const std::vector< T > &x)
Definition: length.hpp:10
stan::math::var
Independent (input) and dependent (output) variables for gradients.
Definition: var.hpp:30
stan::math::sum_v_vari::length_
size_t length_
Definition: sum.hpp:17
stan::math::sum_v_vari::chain
virtual void chain()
Apply the chain rule to this variable based on the variables on which it depends. ...
Definition: sum.hpp:40
stan::math::size
int size(const std::vector< T > &x)
Return the size of the specified standard vector.
Definition: size.hpp:17
stan::math::AutodiffStackStorage
Definition: autodiffstackstorage.hpp:12
stan::math::vari::adj_
double adj_
The adjoint of this variable, which is the partial derivative of this variable with respect to the ro...
Definition: vari.hpp:44
stan::math::sum_v_vari::sum_of_val
static double sum_of_val(const std::vector< var > &v)
Definition: sum.hpp:19
stan::math::sum_v_vari
Class for sums of variables constructed with standard vectors.
Definition: sum.hpp:14
stan::math::sum_v_vari::sum_v_vari
sum_v_vari(const std::vector< var > &v1)
Definition: sum.hpp:31

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