MATLAB Function Reference |

Symbolic factorization analysis

**Syntax**

count = symbfact(A) count = symbfact(A,'col') count = symbfact(A,'sym') [count,h,parent,post,R] = symbfact(...)

**Description**

```
count = symbfact(A)
```

returns the vector of row counts for the upper triangular Cholesky factor of a symmetric matrix whose upper triangle is that of `A`

, assuming no cancellation during the factorization. `symbfact`

should be much faster than `chol`

(`A`

).

```
count = symbfact(A,'col')
```

analyzes `A`

' `*A`

(without forming it explicitly).

```
count = symbfact(A,'sym')
```

is the same as `count = symbfact(A)`

.

```
[count,h,parent,post,R] = symbfact(...)
```

has several optional return values.

`h` |
Height of the elimination tree |

`parent` |
The elimination tree itself |

`post` |
Postordering permutation of the elimination tree |

`R` |
0-1 matrix whose structure is that of `chol` (`A` ) |

**See Also**

symamd | symmlq |