Stan Math Library  2.12.0
reverse mode automatic differentiation
acos.hpp
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1 #ifndef STAN_MATH_FWD_SCAL_FUN_ACOS_HPP
2 #define STAN_MATH_FWD_SCAL_FUN_ACOS_HPP
3 
4 #include <stan/math/fwd/core.hpp>
6 #include <cmath>
7 
8 namespace stan {
9  namespace math {
10 
11  template <typename T>
12  inline
13  fvar<T>
14  acos(const fvar<T>& x) {
15  using std::acos;
16  using std::sqrt;
17  return fvar<T>(acos(x.val_), x.d_ / -sqrt(1 - square(x.val_)));
18  }
19 
20  }
21 }
22 #endif
fvar< T > sqrt(const fvar< T > &x)
Definition: sqrt.hpp:14
fvar< T > square(const fvar< T > &x)
Definition: square.hpp:14
var acos(const var &a)
Return the principal value of the arc cosine of a variable, in radians (cmath).
Definition: acos.hpp:59
fvar< T > acos(const fvar< T > &x)
Definition: acos.hpp:14

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