xpnd {MCMCpack} | R Documentation |

## Expand a Vector into a Symmetric Matrix

### Description

This function takes a vector of appropriate length (typically
created using `vech`

) and creates a symmetric matrix.

### Usage

xpnd(x, nrow)

### Arguments

`x` |
A list of elements to expand into symmetric matrix. |

`nrow` |
The number of rows (and columns) in the returned matrix. |

### Details

This function is particularly useful when dealing with variance
covariance matrices. Note that R stores matrices in column major
order, and that the items in `x`

will be recycled to fill the
matrix if need be.

### Value

An *(nrows * nrows)* symmetric matrix.

### See Also

`vech`

### Examples

xpnd(c(1,2,3,4,4,5,6,7,8,9),4)

[Package

*MCMCpack* version 0.5-2

Index]