AM_mix_components_prior_negbin {AntMAN} | R Documentation |
Generate a configuration object for a Shifted Negative Binomial prior on the number of mixture components
Description
This generates a configuration object for a Shifted Negative Binomial prior on the number of mixture components such that
q_M(m)=Pr(M=m) =\frac{\Gamma(r+m-1)}{(m-1)!\Gamma(r)} p^{m-1}(1-p)^r, \quad m=1,2,3,\ldots
The hyperparameters p\in (0,1)
(probability of success) and r>0
(size) can either be fixed using r
and p
or assigned appropriate prior distributions.
In the latter case, we assume p \sim Beta(a_P,b_P)
and r \sim Gamma(a_R,b_R)
. In AntMAN we assume the following
parametrization of the Gamma density:
p(x\mid a,b )= \frac{b^a x^{a-1}}{\Gamma(a)} \exp\{ -bx \}, \quad x>0.
Usage
AM_mix_components_prior_negbin(
a_R = NULL,
b_R = NULL,
a_P = NULL,
b_P = NULL,
R = NULL,
P = NULL,
init_R = NULL,
init_P = NULL
)
Arguments
a_R |
The shape parameter |
b_R |
The rate parameter |
a_P |
The parameter |
b_P |
The parameter |
R |
It allows to fix |
P |
It allows to fix |
init_R |
The initial value of |
init_P |
The inivial value of |
Details
If no arguments are provided, the default is r = 1 , a_P = 1, b_P = 1
.
Additionally, when init_R and init_P are not specified, there are default values:
init_R = 1
and init_P = 0.5
.
Value
An AM_mix_components_prior
object. This is a configuration list to be used as mix_components_prior
argument for AM_mcmc_fit
.
See Also
Examples
AM_mix_components_prior_negbin (R=1, P=1)
AM_mix_components_prior_negbin ()