# utilityfunctions: Cumulative and incremental triangles In ChainLadder: Statistical Methods and Models for Claims Reserving in General Insurance

## Description

Functions to convert between cumulative and incremental triangles

## Usage

 ```1 2``` ```incr2cum(Triangle, na.rm=FALSE) cum2incr(Triangle) ```

## Arguments

 `Triangle` triangle. Assume columns are the development period, use transpose otherwise. `na.rm` logical. Should missing values be removed?

## Details

`incr2cum` transforms an incremental triangle into a cumulative triangle, `cum2incr` provides the reserve operation.

## Value

Both functions return a `triangle`.

## Author(s)

Markus Gesmann, Christophe Dutang

See also `as.triangle`
 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26``` ```# See the Taylor/Ashe example in Mack's 1993 paper #original triangle GenIns #incremental triangle cum2incr(GenIns) #original triangle incr2cum(cum2incr(GenIns)) # See the example in Mack's 1999 paper #original triangle Mortgage incMortgage <- cum2incr(Mortgage) #add missing values incMortgage[1,1] <- NA incMortgage[2,1] <- NA incMortgage[1,2] <- NA #with missing values argument incr2cum(incMortgage, na.rm=TRUE) #compared to incr2cum(Mortgage) ```