Parent class for
PipeOps that aggregate predictions. Implements the
$predict_internal() methods necessary
PipeOp and requires deriving classes to create the
PipeOpEnsemble$new(innum = 0, id, param_set = ParamSet$new(), param_vals = list(), packages = character(0), prediction_type = "Prediction")
numeric(1)Determines the number of input channels. If
innumis 0 (default), a vararg input channel is created that can take an arbitrary number of inputs.
character(1)Identifier of the resulting object.
listList of hyperparameter settings, overwriting the hyperparameter settings that would otherwise be set during construction. Default
characterSet of packages required for this
PipeOp. These packages are loaded during
$predict(), but not attached. Default
predictentry of the
$outputtype specifications. Should be
"Prediction"(default) or one of its subclasses, e.g.
"PredictionClassif", and correspond to the type accepted by
Input and Output Channels
PipeOpEnsemble has multiple input channels depending on the
innum construction argument, named
innum is nonzero; if
innum is 0, there is only one vararg input channel named
All input channels take only
NULL during training and take a
Prediction during prediction.
The output during prediction is in some way a weighted averaged representation of the input.
$state is left empty (
numericRelative weights of input predictions. If this has length 1, it is ignored and weighs all inputs equally. Otherwise it must have length equal to the number of connected inputs. Initialized to 1 (equal weights).
The commonality of ensemble methods using
PipeOpEnsemble is that they take a
NULL-input during training and save an empty
$state. They can be
used following a set of
PipeOps to perform (possibly weighted) prediction averaging. See e.g.
PipeOpRegrAvg which both inherit from this class.
Should it be necessary to use the output of preceding
during the "training" phase, then
PipeOpEnsemble should not be used. In fact, if training time behaviour of a
Learner is important, then
one should use a
PipeOpLearnerCV instead of a
PipeOpLearner, and the ensemble can be created with a
Learner encapsulated by a
LearnerRegrAvg for examples.
Only fields inherited from
Methods inherited from
PipeOp as well as:
weighted_avg_prediction(inputs, weights, row_ids, truth)(
Predictions that correspond to the weighted average of incoming
Predictions. This is called by
$predict_internal()with cleaned and sanity-checked values:
inputsare guaranteed to fit together,
truthare guaranteed to be the same as each one in
weightsis guaranteed to have the same length as
inputs. This method is abstract, it must be implemented by deriving classes.