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lbeta.hpp
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1 #ifndef STAN__MATH__FUNCTIONS__LBETA_HPP
2 #define STAN__MATH__FUNCTIONS__LBETA_HPP
3 
4 #include <boost/math/tools/promotion.hpp>
5 
6 #include <boost/math/special_functions/gamma.hpp>
7 
8 namespace stan {
9  namespace math {
10 
57  template <typename T1, typename T2>
58  inline typename boost::math::tools::promote_args<T1,T2>::type
59  lbeta(const T1 a, const T2 b) {
60  using boost::math::lgamma;
61  return lgamma(a)
62  + lgamma(b)
63  - lgamma(a + b);
64  }
65 
66  }
67 }
68 
69 #endif
stan::agrad::lgamma
fvar< T > lgamma(const fvar< T > &x)
Definition: lgamma.hpp:15
stan::math::lbeta
boost::math::tools::promote_args< T1, T2 >::type lbeta(const T1 a, const T2 b)
Return the log of the beta function applied to the specified arguments.
Definition: lbeta.hpp:59
stan::math::lgamma
double lgamma(double x)
Definition: lgamma.hpp:31
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