Stan Math Library
4.9.0
Automatic Differentiation
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Returns the natural logarithm of the beta function and its gradients.
\[ \mathrm{lbeta}(a,b) = \ln\left(B\left(a,b\right)\right) \]
\[ \frac{\partial }{\partial b} = \psi^{\left(0\right)}\left(b\right) - \psi^{\left(0\right)}\left(a + b\right) \]
a | double Argument |
b | var Argument |