The Frobenius-norm is defined for the Matrix concept. The value_type must be a model of the Field concept, so that we have a vector space.
The Frobenius-norm is defined as
| Parameter | Description | Default |
| V | Matrix type |
| Member | Where defined | Comment |
| real_type | BanachSpace | |
| norm() | BanachSpace | Returns the Frobenius-norm. |