Stan Math Library  2.14.0
reverse mode automatic differentiation
cbrt.hpp
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1 #ifndef STAN_MATH_REV_SCAL_FUN_CBRT_HPP
2 #define STAN_MATH_REV_SCAL_FUN_CBRT_HPP
3 
5 #include <stan/math/rev/core.hpp>
6 
7 
8 namespace stan {
9  namespace math {
10 
11  namespace {
12  class cbrt_vari : public op_v_vari {
13  public:
14  explicit cbrt_vari(vari* avi) :
15  op_v_vari(cbrt(avi->val_), avi) {
16  }
17  void chain() {
18  avi_->adj_ += adj_ / (3.0 * val_ * val_);
19  }
20  };
21  }
22 
49  inline var cbrt(const var& a) {
50  return var(new cbrt_vari(a.vi_));
51  }
52 
53  }
54 }
55 #endif
fvar< T > cbrt(const fvar< T > &x)
Return cube root of specified argument.
Definition: cbrt.hpp:18
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

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