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mvpa2.mappers.mdp_adaptor.PCAMapper

class mvpa2.mappers.mdp_adaptor.PCAMapper(alg='PCA', nodeargs=None, **kwargs)

Convenience wrapper to perform PCA using MDP’s Mapper

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 :

alg : {‘PCA’, ‘NIPALS’}

Which MDP implementation of a PCA to use.

nodeargs : None or dict

Arguments passed to the MDP node in various stages of its lifetime. See the MDPNodeMapper for more details.

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

node : mdp.Node instance

This node instance is taken as the pristine source of which a copy is made for actual processing upon each training attempt.

centroid

Mean of the traiing data

proj

Projection matrix (as an array)

recon

Backprojection matrix (as an array)

var

Variances per component