low_var_sample {animalEKF} | R Documentation |

## Sample particles using low-variance sampling.

### Description

Sample particles using low-variance sampling.

### Usage

```
low_var_sample(wts, M=length(wts))
```

### Arguments

`wts` |
Vector of weights. |

`M` |
The number of items to sample. When resampling, should be number of particles |

### Details

Low-variance sampling guarantees items will be sampled in proportion to their weights. With random sampling with replacement (`sample`

function), there is some variability in the final proportions of items.

### Value

A numeric vector of length `M`

.

### Author(s)

Samuel Ackerman

### References

James Edward Baker. Reducing bias and inefficiency in the selection algorithm. Proceedings of the Second International Conference on Genetic Algorithms on Genetic Algorithms and Their Application, 1987.

### Examples

```
n <- 20
w <- runif(n)
#can use M != to length(wts)
low_var_sample(wts=w, M=15)
lv <- low_var_sample(wts=w, M=n)
#usual resampling with weights
a <- sample(x=1:n, size=n, prob=w, replace=TRUE)
#the first should be more in proportion to weights
table(lv)/n
table(a)/n
#proportions
w/sum(w)
```

[Package

*animalEKF*version 1.2 Index]