`object`

, or the objective value with respect to a given
target matrix `y`

if it is supplied.Returns the objective function associated with the
algorithm that computed the fitted NMF model
`object`

, or the objective value with respect to a
given target matrix `y`

if it is supplied.

```
S4 (NMFfit)
`objective`(object, y)
```

- y
- optional target matrix used to compute the objective value.
- object
- an object computed using some algorithm, or that describes an algorithm itself.