Stan Math Library  2.15.0
reverse mode automatic differentiation
log1m_exp.hpp
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1 #ifndef STAN_MATH_FWD_SCAL_FUN_LOG1M_EXP_HPP
2 #define STAN_MATH_FWD_SCAL_FUN_LOG1M_EXP_HPP
3 
4 #include <stan/math/fwd/core.hpp>
10 
11 namespace stan {
12  namespace math {
13 
22  template <typename T>
23  inline fvar<T> log1m_exp(const fvar<T>& x) {
24  if (x.val_ >= 0)
25  return fvar<T>(NOT_A_NUMBER);
26  return fvar<T>(log1m_exp(x.val_), x.d_ / -expm1(-x.val_));
27  }
28 
29  }
30 }
31 #endif
const double NOT_A_NUMBER
(Quiet) not-a-number value.
Definition: constants.hpp:55
fvar< T > expm1(const fvar< T > &x)
Definition: expm1.hpp:12
fvar< T > log1m_exp(const fvar< T > &x)
Return the natural logarithm of one minus the exponentiation of the specified argument.
Definition: log1m_exp.hpp:23

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