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Transformer (Pairwise Panel)

PwTrafoPanelPipeline

API referenceSource
MultivariateUnequal lengthMissing values

Pipeline of transformers and a pairwise panel transformer.

PwTrafoPanelPipeline chains transformers and a pairwise transformer at the end. The pipeline is constructed with a list of sktime transformers (BaseTransformer),

plus a pairwise panel transformer, following BasePairwiseTransformerPanel.

The transformer list can be unnamed - a simple list of transformers -

or string named - a list of pairs of string, estimator.

For a list of transformers trafo1, trafo2, …, trafoN and an estimator est,

the pipeline behaves as follows:

transform(X) - running trafo1.fit_transform on X,

them trafo2.fit_transform on the output of trafo1.fit_transform, etc sequentially, with trafo[i] receiving the output of trafo[i-1]. Then passes output of trafo[N] to pw_trafo.transform, as X. Same chain of transformers is run on X2 and passed, if not None.

PwTrafoPanelPipeline can also be created by using the magic multiplication
on any parameter estimator: if pw_t is BasePairwiseTransformerPanel,

and my_trafo1, my_trafo2 inherit from BaseTransformer, then, for instance, my_trafo1 * my_trafo2 * pw_t will result in the same object as obtained from the constructor PwTrafoPanelPipeline(pw_trafo=pw_t, transformers=[my_trafo1, my_trafo2])

magic multiplication can also be used with (str, transformer) pairs,

as long as one element in the chain is a transformer

Quickstart

python
from sktime.dists_kernels.compose import PwTrafoPanelPipeline

estimator = PwTrafoPanelPipeline(pw_trafo, transformers)

Parameters(2)

pw_trafopairwise panel transformer,

i.e., estimator inheriting from BasePairwiseTransformerPanel this is a “blueprint” estimator, state does not change when fit is called

transformerslist of sktime transformers, or

list of tuples (str, transformer) of sktime transformers these are “blueprint” transformers, states do not change when fit is called

Examples

>>> from sktime.dists_kernels.compose import PwTrafoPanelPipeline
>>> from sktime.dists_kernels.dtw import DtwDist
>>> from sktime.transformations.exponent import ExponentTransformer
>>> from sktime.datasets import load_unit_test
>>> 
>>> X, _ = load_unit_test ()
>>> X = X [0: 3 ]
>>> pipeline = PwTrafoPanelPipeline (DtwDist (), [ExponentTransformer ()])
>>> dist_mat = pipeline. transform (X)