Stan Math Library  2.9.0
reverse mode automatic differentiation
sqrt.hpp
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1 #ifndef STAN_MATH_FWD_SCAL_FUN_SQRT_HPP
2 #define STAN_MATH_FWD_SCAL_FUN_SQRT_HPP
3 
4 #include <stan/math/fwd/core.hpp>
5 
7 
8 namespace stan {
9 
10  namespace math {
11 
12  template <typename T>
13  inline
14  fvar<T>
15  sqrt(const fvar<T>& x) {
16  using std::sqrt;
18  return fvar<T>(sqrt(x.val_), 0.5 * x.d_ * inv_sqrt(x.val_));
19  }
20  }
21 }
22 #endif
fvar< T > inv_sqrt(const fvar< T > &x)
Definition: inv_sqrt.hpp:15
fvar< T > sqrt(const fvar< T > &x)
Definition: sqrt.hpp:15
var sqrt(const var &a)
Return the square root of the specified variable (cmath).
Definition: sqrt.hpp:50

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