pContrib_locus: Compute the posterior probabilities for Pr(m|n0) for a given...

In DNAtools: Tools for Analysing Forensic Genetic DNA Data

Compute the posterior probabilities for Pr(m|n0) for a given prior Pr(m).

Description

Compute a matrix of posterior probabilties P(m|n0) where m ranges from 1 to \code{m.max}, and n0 is 0,…,\code{m.max}. This is done by evaluating Pr(m|n0)=Pr(n0|m)Pr(m)/Pr(n), where Pr(n0|m) is evaluated by pNoA.

Usage

pContrib_locus(
  prob = NULL,
  m.prior = NULL,
  m.max = 8,
  pnoa.locus = NULL,
  theta = 0
)

Arguments

prob	Vectors with allele probabilities for the specific locus
m.prior	A vector with prior probabilities (summing to 1), where the length of m.prior determines the plausible range of m
m.max	Derived from the length of m.prior, and if m.prior=NULL a uniform prior is speficied by m.max: m.prior = rep(1/m.max,m.max).
pnoa.locus	A named vector of locus specific probabilities P(N(m)=n), n=1,…,2m.
theta	The coancestery coefficient

Details

Computes a matrix of Pr(m|n0) values for a specific locus.

Value

Returns a matrix [Pr(m|n0)] for m = 1,…,m.max and n_0 = 1,…,2m.max.

Author(s)

Torben Tvedebrink, James Curran

References

T. Tvedebrink (2014). 'On the exact distribution of the number of alleles in DNA mixtures', International Journal of Legal Medicine; 128(3):427–37. <https://doi.org/10.1007/s00414-013-0951-3>

Examples

  ## Simulate some allele frequencies:
  freqs <-  simAlleleFreqs()
  
  ## Compute Pr(m|n0) for m = 1, ..., 5 and n0 = 1, ..., 10 for the first locus:
  pContrib_locus(prob = freqs[[1]], m.max = 5)

DNAtools documentation built on March 18, 2022, 7:01 p.m.