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

a	var Argument
b	var Argument

Returns

Result of log beta function

Definition at line 64 of file lbeta.hpp.