fit {NMF} | R Documentation |
Extracting Fitted Models
Description
The functions fit
and minfit
are S4
genetics that extract the best model object and the best
fit object respectively, from a collection of models or
from a wrapper object.
fit<-
sets the fitted model in a fit object. It is
meant to be called only when developing new NMF
algorithms, e.g. to update the value of the model stored
in the starting point.
Usage
fit(object, ...)
fit(object)<-value
minfit(object, ...)
Arguments
object |
an object fitted by some algorithm, e.g. as
returned by the function |
value |
replacement value |
... |
extra arguments to allow extension |
Details
A fit object differs from a model object in that it contains data about the fit, such as the initial RNG settings, the CPU time used, etc..., while a model object only contains the actual modelling data such as regression coefficients, loadings, etc...
That best model is generally defined as the one that achieves the maximum/minimum some quantitative measure, amongst all models in a collection.
In the case of NMF models, the best model is the one that achieves the best approximation error, according to the objective function associated with the algorithm that performed the fit(s).
Methods
- fit
signature(object = "NMFfit")
: Returns the NMF model object stored in slot'fit'
.- fit
signature(object = "NMFfitX")
: Returns the model object that achieves the lowest residual approximation error across all the runs.It is a pure virtual method defined to ensure
fit
is defined for sub-classes ofNMFfitX
, which throws an error if called.- fit
signature(object = "NMFfitX1")
: Returns the model object associated with the best fit, amongst all the runs performed when fittingobject
.Since
NMFfitX1
objects only hold the best fit, this method simply returns the NMF model fitted byobject
– that is stored in slot ‘fit’.- fit
signature(object = "NMFfitXn")
: Returns the best NMF fit object amongst all the fits stored inobject
, i.e. the fit that achieves the lowest estimation residuals.- fit<-
signature(object = "NMFfit", value = "NMF")
: Updates the NMF model object stored in slot'fit'
with a new value.- minfit
signature(object = "NMFfit")
: Returns the object its self, since there it is the result of a single NMF run.- minfit
signature(object = "NMFfitX")
: Returns the fit object that achieves the lowest residual approximation error across all the runs.It is a pure virtual method defined to ensure
minfit
is defined for sub-classes ofNMFfitX
, which throws an error if called.- minfit
signature(object = "NMFfitX1")
: Returns the fit object associated with the best fit, amongst all the runs performed when fittingobject
.Since
NMFfitX1
objects only hold the best fit, this method simply returnsobject
coerced into anNMFfit
object.- minfit
signature(object = "NMFfitXn")
: Returns the best NMF model in the list, i.e. the run that achieved the lower estimation residuals.The model is selected based on its
deviance
value.