# Method var

#### static member var: Tensor<'T> * int64 option -> 'T

Calculates the variance of the tensor.

##### Declaration

`static member var: a:Tensor<'T> * ddof:int64 option -> 'T`

##### Parameters

Type | Name | Description |
---|---|---|

Tensor<'T> | a | The tensor containing the source values. |

int64 option | ddof |

##### Returns

Type | Description |
---|---|

'T | The variance estimate. |

##### Remarks

The variance is calculated over all elements of the tensor.

The parameter `ddof`

specifies the difference between the number of elements and the
degrees of freedom for the computation of the variance. Use `ddof=1`

to obtain an unbiased estimate and
`ddof=0`

for a maximum-likelihood estimate.

##### Examples

```
let a = HostTensor.ofList2D [[1.0; 2.0; 3.0; 4.0]
[5.0; 6.0; 7.0; 8.0]]
let b = Tensor.var a
```