vechs2full {OpenMx} | R Documentation |

## Inverse Strict Half-vectorization

### Description

This function returns the symmetric matrix constructed from a strict half-vectorization.

### Usage

```
vechs2full(x)
```

### Arguments

`x` |
an input single column or single row matrix. |

### Details

The strict half-vectorization of an input matrix consists of the elements in the lower triangle of the matrix, excluding the elements along the diagonal of the matrix, as a column vector. The column vector is created by traversing the matrix in column-major order. The inverse strict half-vectorization takes a vector and reconstructs a symmetric matrix such that `vechs2full(vechs(x))`

is equal to `x`

with zero along the diagonal if `x`

is symmetric.

Note that very few vectors have the correct number of elements to construct a symmetric matrix. For example, vectors with 1, 3, 6, 10, and 15 elements can be used to make a symmetric matrix, but none of the other numbers between 1 and 15 can. An error is thrown if the number of elements in `x`

cannot be used to make a symmetric matrix.

### See Also

`vech2full`

, `vech`

, `vechs`

, `rvectorize`

, `cvectorize`

### Examples

```
vechs2full(1:10)
matrix(1:16, 4, 4)
vechs(matrix(1:16, 4, 4))
vechs2full(vechs(matrix(1:16, 4, 4)))
```

*OpenMx*version 2.21.11 Index]