# pContrib_locus: Compute the posterior probabilities for Pr(m|n0) for a given... In DNAtools: Tools for Analysing Forensic Genetic DNA Data

 pContrib_locus R Documentation

## 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.