R: Helper function for Cox deviance and gradient

fid {glmnet} | R Documentation

## Helper function for Cox deviance and gradient

### Description

Helps to find ties in death times of data.

### Usage

    fid(x, index)

### Arguments

`x` | Sorted vector of death times.
`index` | Vector of indices for the death times.

### Value

A list with two arguments.

`index_first` | A vector of indices for the first observation at each death time as they appear in the sorted list.
`index_ties` | If there are no ties at all, this is NULL. If not, this is a list with length equal to the number of unique times with ties. For each time with ties, index_ties gives the indices of the observations with a death at that time.

### Examples

    # Example with no ties
    glmnet:::fid(c(1, 4, 5, 6), 1:5)

    # Example with ties
    glmnet:::fid(c(1, 1, 1, 2, 3, 3, 4, 4, 4), 1:9)

[Package glmnet version 4.1-2 Index]