Stan Math Library  2.9.0
reverse mode automatic differentiation
expm1.hpp
Go to the documentation of this file.
1 #ifndef STAN_MATH_REV_SCAL_FUN_EXPM1_HPP
2 #define STAN_MATH_REV_SCAL_FUN_EXPM1_HPP
3 
4 #include <math.h>
5 #include <stan/math/rev/core.hpp>
7 #include <cmath>
8 #include <valarray>
9 
10 #ifdef _MSC_VER
11 #include <boost/math/special_functions/expm1.hpp>
12 using boost::math::expm1;
13 #endif
14 
15 namespace stan {
16  namespace math {
17 
18  namespace {
19  class expm1_vari : public op_v_vari {
20  public:
21  explicit expm1_vari(vari* avi) :
22  op_v_vari(::expm1(avi->val_), avi) {
23  }
24  void chain() {
25  avi_->adj_ += adj_ * (val_ + 1.0);
26  }
27  };
28  }
29 
57  inline var expm1(const stan::math::var& a) {
58  return var(new expm1_vari(a.vi_));
59  }
60 
61  }
62 }
63 #endif
Independent (input) and dependent (output) variables for gradients.
Definition: var.hpp:31
var expm1(const stan::math::var &a)
The exponentiation of the specified variable minus 1 (C99).
Definition: expm1.hpp:57
fvar< T > expm1(const fvar< T > &x)
Definition: expm1.hpp:12
vari * vi_
Pointer to the implementation of this variable.
Definition: var.hpp:43

     [ Stan Home Page ] © 2011–2015, Stan Development Team.