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mvpa2.measures.base.Learner

class mvpa2.measures.base.Learner(auto_train=False, force_train=False, **kwargs)

Common trainable processing object.

A Learner is a Node that can (maybe has to) be trained on a dataset, before it can perform its function.

Notes

Available conditional attributes:

• calling_time+: Time (in seconds) it took to call the node
• raw_results: Computed results before invoking postproc. Stored only if postproc is not None.
• training_time+: Time (in seconds) it took to train the learner

(Conditional attributes enabled by default suffixed with +)

Parameters :

auto_train : bool

Flag whether the learner will automatically train itself on the input dataset when called untrained.

force_train : bool

Flag whether the learner will enforce training on the input dataset upon every call.

enable_ca : None or list of str

Names of the conditional attributes which should be enabled in addition to the default ones

disable_ca : None or list of str

Names of the conditional attributes which should be disabled

space: str, optional :

Name of the ‘processing space’. The actual meaning of this argument heavily depends on the sub-class implementation. In general, this is a trigger that tells the node to compute and store information about the input data that is “interesting” in the context of the corresponding processing in the output dataset.

postproc : Node instance, optional

Node to perform post-processing of results. This node is applied in __call__() to perform a final processing step on the to be result dataset. If None, nothing is done.

descr : str

Description of the instance

auto_train

Whether the Learner performs automatic trainingwhen called untrained.

force_train

Whether the Learner enforces training upon everycalled.

is_trained

Whether the Learner is currently trained.

train(ds)

The default implementation calls _pretrain(), _train(), and finally _posttrain().

Parameters :

ds: Dataset :

Training dataset.

Returns :

None :

untrain()

Reverts changes in the state of this node caused by previous training