R: Array: make vector positions from symmetric array index

symmIndex2vectorIndex {ff} | R Documentation

## Array: make vector positions from symmetric array index

### Description

make vector positions from (non-symmetric) array index respecting dim and fixdiag

### Usage

    symmIndex2vectorIndex(x, dim, fixdiag = NULL)

### Arguments

`x` | a matrix[,1:2] with matrix subscripts
`dim` | the dimensions of the symmetric matrix
`fixdiag` | NULL assumes free diagonal, any value assumes fixed diagonal

### Details

With fixdiag = NULL

### Value

a vector of indices in `1:prod(dim(x))`

### Author(s)

Jens Oehlschlägel

### See Also

`arrayIndex2vectorIndex`

### Examples

      symmIndex2vectorIndex(rbind(
       c(1,1)
      ,c(1,10)
      ,c(10,1)
      ,c(10,10)
      ), dim=c(10,10))
      symmIndex2vectorIndex(rbind(
       c(1,1)
      ,c(1,10)
      ,c(10,1)
      ,c(10,10)
      ), dim=c(10,10), fixdiag=1)

[Package ff version 2.2-13 Index]