PTBdefault {accuracy} | R Documentation

## Returns a default perturbation function for a given vector.

### Description

This function returns a function that can be used to repeatedly peturb the vector given to it.

### Usage

    PTBdefaultfn(vec, q = 0.99)
    PTBdefault(vec, q=0.99)

### Arguments

`vec` | the vector which will be subject to perturbation
`q` | for discrete vectors, the reclassification probability. For continuous vectors, perturbations will have 1-q relative uniform noise added.

### Details

For numeric discrete values, and ordered factors, `reclass.mat.diag` will be used to generate the default reclassification matrix. For character vectors, unordered factors, and logicals, `relass.mat.random` is used.

### Value

A function that can be used to perturb the vector.

### Author(s)

Micah Altman Micah_Altman@harvard.edu http://www.hmdc.harvard.edu/micah_altman/

### References

Altman, M., J. Gill and M. P. McDonald. 2003. Numerical Issues in Statistical Computing for the Social Scientist. John Wiley & Sons. http://www.hmdc.harvard.edu/numerical_issues/

### See Also

`perturb`, `PTBdiscrete`, `PTBus`, `reclass.mat.random`

### Examples

    x=1:100
     # perturb using the default method
    rpx=replicate(100,PTBdefault(x),simplify=FALSE)
    # how many matches to original vector? mean should be close to 95
            if (is.R()) {
         matches <-sapply(rpx,function(y)(sum(y==x)))       # how many matches to original vector
      } else {
         # Splus variation
         matches <-sapply(rpx,substitute(function(y)(sum(y==x))))
      }
    summary(matches)
    # This produces equivalent results, but is faster,
    # since reclass matrices are not recalculated on each replication

    fx=PTBdefaultfn(x,q=.95)
    rpx=replicate(100,fx(x),simplify=FALSE)
            if (is.R()) {
         matches <-sapply(rpx,function(y)(sum(y==x)))       # how many matches to original vector
      } else {
         # Splus variation
         matches <-sapply(rpx,substitute(function(y)(sum(y==x))))
      }
    summary(matches)

[Package accuracy version 1.35 Index]