Source: Wikipedia, the free encyclopedia.
Continuous probability distribution
Lewandowski-Kurowicka-Joe distribution Notation
LKJ
(
η
)
{\displaystyle \operatorname {LKJ} (\eta )}
Parameters
η
∈
(
0
,
∞
)
{\displaystyle \eta \in (0,\infty )}
(shape) Support
R
{\displaystyle \mathbf {R} }
is a positive-definite matrix with unit diagonal Mean
the identity matrix
In
probabilistic programming language and as a library linked to the
Turing.jl probabilistic programming library in
Julia .
The distribution has a single shape parameter
η
{\displaystyle \eta }
and the probability density function for a
d
×
d
{\displaystyle d\times d}
matrix
R
{\displaystyle \mathbf {R} }
is
p
(
R
;
η
)
=
C
×
[
det
(
R
)
]
η
−
1
{\displaystyle p(\mathbf {R} ;\eta )=C\times [\det(\mathbf {R} )]^{\eta -1}}
with normalizing constant
C
=
2
∑
k
=
1
d
(
2
η
−
2
+
d
−
k
)
(
d
−
k
)
∏
k
=
1
d
−
1
[
B
(
η
+
(
d
−
k
−
1
)
/
2
,
η
+
(
d
−
k
−
1
)
/
2
)
]
d
−
k
{\displaystyle C=2^{\sum _{k=1}^{d}(2\eta -2+d-k)(d-k)}\prod _{k=1}^{d-1}\left[B\left(\eta +(d-k-1)/2,\eta +(d-k-1)/2\right)\right]^{d-k}}
, a complicated expression including a product over Beta functions . For
η
=
1
{\displaystyle \eta =1}
, the distribution is uniform over the space of all correlation matrices; i.e. the space of positive definite matrices with unit diagonal.
References
External links
Discrete univariate
with finite support with infinite support
Continuous univariate
supported on a bounded interval supported on a semi-infinite interval supported on the whole real line with support whose type varies
Mixed univariate
Multivariate (joint) Directional Degenerate and singular Families