mvpa2.mappers.fx.FxMapper

class mvpa2.mappers.fx.FxMapper(axis, fx, fxargs=None, uattrs=None, attrfx='merge', order='uattrs')

Apply a custom transformation to (groups of) samples or features.

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.
• trained_dataset: The dataset it has been trained on
• trained_nsamples+: Number of samples it has been trained on
• trained_targets+: Set of unique targets (or any other space) it has been trained on (if present in the dataset trained on)
• training_time+: Time (in seconds) it took to train the learner

(Conditional attributes enabled by default suffixed with +)

Attributes

attrfx
auto_train	Whether the Learner performs automatic trainingwhen called untrained.
axis
descr	Description of the object if any
force_train	Whether the Learner enforces training upon every call.
fx
fxargs
order
pass_attr	Which attributes of the dataset or self.ca to pass into result dataset upon call
postproc	Node to perform post-processing of results
space	Processing space name of this node
uattrs

Methods

__call__(ds)
forward(data)	Map data from input to output space.
forward1(data)	Wrapper method to map single samples.
generate(ds)	Yield processing results.
get_postproc()	Returns the post-processing node or None.
get_space()	Query the processing space name of this node.
reset()
reverse(data)	Reverse-map data from output back into input space.
reverse1(data)	Wrapper method to map single samples.
set_postproc(node)	Assigns a post-processing node
set_space(name)	Set the processing space name of this node.
train(ds)	The default implementation calls _pretrain(), _train(), and finally _posttrain().
untrain()	Reverts changes in the state of this node caused by previous training

Parameters:

axis : {‘samples’, ‘features’}

fx : callable

fxargs : tuple

Passed as *args to fx

uattrs : list

List of attribute names to consider. All possible combinations of unique elements of these attributes are used to determine the sample groups to operate on.

attrfx : callable

Functor that is called with each sample attribute elements matching the respective samples group. By default the unique value is determined. If the content of the attribute is not uniform for a samples group a unique string representation is created. If None, attributes are not altered.

order : {‘uattrs’, ‘occurrence’, None}

If which order groups should be merged together. If None (default before 2.3.1), the order is imposed only by the order of uattrs as keys in the dictionary, thus can vary from run to run. If 'occurrence', groups will be ordered by the first occurrence of group samples in original dataset. If 'uattrs', groups will be sorted by the values of uattrs with follow-up attr having higher importance for ordering (e .g. uattrs=['targets', 'chunks'] would order groups first by chunks and then by targets within each chunk).

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

Attributes

attrfx
auto_train	Whether the Learner performs automatic trainingwhen called untrained.
axis
descr	Description of the object if any
force_train	Whether the Learner enforces training upon every call.
fx
fxargs
order
pass_attr	Which attributes of the dataset or self.ca to pass into result dataset upon call
postproc	Node to perform post-processing of results
space	Processing space name of this node
uattrs

Methods

__call__(ds)
forward(data)	Map data from input to output space.
forward1(data)	Wrapper method to map single samples.
generate(ds)	Yield processing results.
get_postproc()	Returns the post-processing node or None.
get_space()	Query the processing space name of this node.
reset()
reverse(data)	Reverse-map data from output back into input space.
reverse1(data)	Wrapper method to map single samples.
set_postproc(node)	Assigns a post-processing node
set_space(name)	Set the processing space name of this node.
train(ds)	The default implementation calls _pretrain(), _train(), and finally _posttrain().
untrain()	Reverts changes in the state of this node caused by previous training

attrfx

axis

fx

fxargs

is_trained = True

Indicate that this mapper is always trained.

order

uattrs