Stan Math Library  2.14.0
reverse mode automatic differentiation
exp2.hpp
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1 #ifndef STAN_MATH_REV_SCAL_FUN_EXP2_HPP
2 #define STAN_MATH_REV_SCAL_FUN_EXP2_HPP
3 
4 #include <stan/math/rev/core.hpp>
6 #include <cmath>
7 #include <valarray>
8 
9 namespace stan {
10  namespace math {
11 
12  namespace {
13  class exp2_vari : public op_v_vari {
14  public:
15  explicit exp2_vari(vari* avi) :
16  op_v_vari(std::pow(2.0, avi->val_), avi) {
17  }
18  void chain() {
19  avi_->adj_ += adj_ * val_ * LOG_2;
20  }
21  };
22  }
23 
50  inline var exp2(const var& a) {
51  return var(new exp2_vari(a.vi_));
52  }
53 
54  }
55 }
56 #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 > exp2(const fvar< T > &x)
Definition: exp2.hpp:14
fvar< T > pow(const fvar< T > &x1, const fvar< T > &x2)
Definition: pow.hpp:17

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