Distances and Objective Functions
The NMF package defines methods for the generic
deviance
from the package stats
, to compute
approximation errors between NMF models and matrices,
using a variety of objective functions.
nmfDistance
returns a function that computes the
distance between an NMF model and a compatible matrix.
deviance(object, ...) ## S4 method for signature 'NMF' deviance(object, y, method = c("", "KL", "euclidean"), ...) nmfDistance(method = c("", "KL", "euclidean")) ## S4 method for signature 'NMFfit' deviance(object, y, method, ...) ## S4 method for signature 'NMFStrategy' deviance(object, x, y, ...)
y |
a matrix compatible with the NMF model
|
method |
a character string or a function with
signature |
... |
extra parameters passed to the objective function. |
x |
an NMF model that estimates |
object |
an object for which the deviance is desired. |
deviance
returns a nonnegative numerical value
nmfDistance
returns a function with least two
arguments: an NMF model and a matrix.
signature(object = "NMF")
:
Computes the distance between a matrix and the estimate
of an NMF
model.
signature(object = "NMFfit")
:
Returns the deviance of a fitted NMF model.
This method returns the final residual value if the
target matrix y
is not supplied, or the
approximation error between the fitted NMF model stored
in object
and y
. In this case, the
computation is performed using the objective function
method
if not missing, or the objective of the
algorithm that fitted the model (stored in slot
'distance'
).
If not computed by the NMF algorithm itself, the value is
automatically computed at the end of the fitting process
by the function nmf
, using the objective
function associated with the NMF algorithm, so that it
should always be available.
signature(object = "NMFfitX")
:
Returns the deviance achieved by the best fit object,
i.e. the lowest deviance achieved across all NMF runs.
signature(object = "NMFStrategy")
:
Computes the value of the objective function between the
estimate x
and the target y
.
Other stats: deviance,NMF-method
,
hasTrack
, residuals
,
residuals<-
, trackError
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