Automatic Differentiation
 
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◆ lbeta() [8/10]

var stan::math::lbeta ( const var a,
const var b 
)
inline

Returns the natural logarithm of the beta function and its gradients.

\[ \mathrm{lbeta}(a,b) = \ln\left(B\left(a,b\right)\right) \]

\[ \frac{\partial }{\partial a} = \psi^{\left(0\right)}\left(a\right) - \psi^{\left(0\right)}\left(a + b\right) \]

\[ \frac{\partial }{\partial b} = \psi^{\left(0\right)}\left(b\right) - \psi^{\left(0\right)}\left(a + b\right) \]

Parameters
avar Argument
bvar Argument
Returns
Result of log beta function

Definition at line 64 of file lbeta.hpp.