Stan Math Library  2.12.0
reverse mode automatic differentiation
log2.hpp
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1 #ifndef STAN_MATH_REV_SCAL_FUN_LOG2_HPP
2 #define STAN_MATH_REV_SCAL_FUN_LOG2_HPP
3 
4 #include <stan/math/rev/core.hpp>
7 
8 namespace stan {
9  namespace math {
10 
11  namespace {
12  class log2_vari : public op_v_vari {
13  public:
14  explicit log2_vari(vari* avi) :
15  op_v_vari(log2(avi->val_), avi) {
16  }
17  void chain() {
18  avi_->adj_ += adj_ / (LOG_2 * avi_->val_);
19  }
20  };
21  }
22 
53  inline var log2(const var& a) {
54  return var(new log2_vari(a.vi_));
55  }
56 
57  }
58 }
59 #endif
const double LOG_2
The natural logarithm of 2, .
Definition: constants.hpp:32
Independent (input) and dependent (output) variables for gradients.
Definition: var.hpp:30
vari * vi_
Pointer to the implementation of this variable.
Definition: var.hpp:42
fvar< T > log2(const fvar< T > &x)
Definition: log2.hpp:14

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