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binary_log_loss.hpp
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1 #ifndef STAN_MATH_REV_SCAL_FUN_BINARY_LOG_LOSS_HPP
2 #define STAN_MATH_REV_SCAL_FUN_BINARY_LOG_LOSS_HPP
3
4 #include <stan/math/rev/core.hpp>
5 #include <stan/math/prim/scal/fun/constants.hpp>
6 #include <stan/math/prim/scal/fun/log1p.hpp>
7 #include <valarray>
8
9 namespace stan {
10 namespace math {
11
12 namespace {
13 class binary_log_loss_1_vari : public op_v_vari {
14 public:
15 explicit binary_log_loss_1_vari(vari* avi) :
16 op_v_vari(-std::log(avi->val_), avi) {
17 }
18 void chain() {
19 avi_->adj_ -= adj_ / avi_->val_;
20 }
21 };
22
23 class binary_log_loss_0_vari : public op_v_vari {
24 public:
25 explicit binary_log_loss_0_vari(vari* avi) :
26 op_v_vari(-stan::math::log1p(-avi->val_), avi) {
27 }
28 void chain() {
29 avi_->adj_ += adj_ / (1.0 - avi_->val_);
30 }
31 };
32 }
33
68 inline var binary_log_loss(const int y, const stan::math::var& y_hat) {
69 if (y == 0)
70 return var(new binary_log_loss_0_vari(y_hat.vi_));
71 else
72 return var(new binary_log_loss_1_vari(y_hat.vi_));
73 }
74
75 }
76 }
77 #endif
core.hpp
stan::math::binary_log_loss
fvar< T > binary_log_loss(const int y, const fvar< T > &y_hat)
Definition: binary_log_loss.hpp:15
stan::math::log
fvar< T > log(const fvar< T > &x)
Definition: log.hpp:15
stan::math::var
Independent (input) and dependent (output) variables for gradients.
Definition: var.hpp:32
stan::math::var::vi_
vari * vi_
Pointer to the implementation of this variable.
Definition: var.hpp:44
constants.hpp
stan::math::log1p
fvar< T > log1p(const fvar< T > &x)
Definition: log1p.hpp:16
log1p.hpp

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