add.jitter {UCS} | R Documentation |

## Random Jitter for Frequency Signatures in Data Set (gam)

### Description

Add random *jitter* to the frequency signatures in a data set, in
order to avoid ties in rankings according to GAM scores and to facilitate
visualisation of the data set with eo and ebo plots. The
`add.ebo`

function is used to re-compute ebo-coordinates from
the jittered frequency signatures.

### Usage

add.jitter(ds, amount=0.5, overwrite=FALSE)
has.jitter(ds, fail=FALSE)
add.ebo(ds, jitter=FALSE)

### Arguments

`ds` |
a UCS data set object |

`amount` |
amount of jitter to be added; the jitter vector for each
coordinate (`f, f1, f2` ) has a uniform distribution over the
range `[-amount, +amount]` |

`overwrite` |
if `TRUE` , overwrite existing jitter vectors in
the data set |

`fail` |
if `TRUE` , abort with an error message unless the
data set contains jitter vectors |

`jitter` |
if `TRUE` , use the jittered frequency signatures to
compute ebo-coordinates (default: unjittered integer frequencies) |

### Details

The `add.jitter`

function adds jitter vectors for the joint and
marginal frequencies (`f, f1, f2`

) to a data set, i.e. uniformly
distributed random numbers in the range `[-amount, +amount]`

.
These vectors are stored in variables `x.jitter.f`

,
`x.jitter.f1`

and `x.jitter.f2`

, where they can be used by
`add.ebo`

, `add.gams`

and other functions.
`has.jitter`

tests for the presence of these variables.

`add.ebo`

computes ebo-coordinates from the frequency signatures
and stores them in the standard variables `e, b, o`

. Unlike the
values computed with UCS/Perl tools, `add.ebo`

uses jitter
vectors in this computation when the option `jitter=TRUE`

is passed.

### Value

`add.jitter`

and `add.ebo`

return a copy of the data set
`ds`

with the request variables added. `has.jitter`

returns
`TRUE`

if the jitter variables are present in `ds`

, and
`FALSE`

otherwise.

### See Also

`add.gams`

, `gamma.nbest`

### Examples

ds <- add.jitter(ds, amount=0.2)
ds <- add.ebo(ds, jitter=TRUE) # recompute ebo coordinates with jitter

[Package

*UCS* version 0.5

Index]