MATLAB Function Reference |

**Syntax**

**Description**

```
p = etree(A)
```

returns an elimination tree for the square symmetric matrix whose upper triangle is that of `A`

. `p(j)`

is the parent of column `j`

in the tree, or `0`

if `j`

is a root.

```
p = etree(A,'col')
```

returns the elimination tree of `A'*A`

.

```
p = etree(A,'sym')
```

is the same as `p = etree(A)`

.

```
[p,q] = etree(...)
```

also returns a postorder permutation `q`

of the tree.

**See Also**

`treelayout`

, `treeplot`

, `etreeplot`

etime | etreeplot |