normexp {limma} | R Documentation

## Normal + Exponential Log-Likelihood

### Description

Marginal log-likelihood of foreground values for normal + exponential model and its derivatives. These functions are called by `normexp.fit` and are not normally called directly by the user.

### Usage

    normexp.m2loglik(par,x)
    normexp.grad(par,x)

### Arguments

`par` | numeric vector of parameters
`x` | numeric vector of (background corrected) intensities

### Details

The parameter vector `par` holds the normal mean, the normal log-standard deviation and the exponential mean.

Computes minus twice the log-likelihood based on the $normal(μ,σ^2)+exponential(α)$ convolution model for the foreground intensities. The elements of `par` are $μ$, $log(σ)$ and $log(α)$.

### Value

`normexp.m2loglik` returns a numeric scalar holding minus-twice the log-likelihood. `normexp.grad` returns a numeric vector holding the derivatives with respect to the elements of `par`.

### Author(s)

Jeremy Silver and Gordon Smyth

### See Also

An overview of background correction functions is given in `04.Background`.

[Package limma version 2.8.1 Index]