Stan Math Library  2.8.0
reverse mode automatic differentiation
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inv_square.hpp
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1 #ifndef STAN_MATH_FWD_SCAL_FUN_INV_SQUARE_HPP
2 #define STAN_MATH_FWD_SCAL_FUN_INV_SQUARE_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  inv_square(const fvar<T>& x) {
16  using stan::math::square;
17  T square_x(square(x.val_));
18  return fvar<T>(1 / square_x, -2 * x.d_ / (square_x * x.val_));
19  }
20  }
21 }
22 #endif
fvar< T > square(const fvar< T > &x)
Definition: square.hpp:15
fvar< T > inv_square(const fvar< T > &x)
Definition: inv_square.hpp:15

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