ComponentLink

class glue.core.component_link.ComponentLink(comp_from, comp_to, using=None, inverse=None)

Bases: object

ComponentLinks represent transformation logic between ComponentIDs

ComponentLinks are be used to derive one ComponentID from another:

Example:

def hours_to_minutes(hours):
    return hours * 60

d = Data(hour=[1, 2, 3])
hour = d.id['hour']
minute = ComponentID('minute')
link = ComponentLink( [hour], minute, using=hours_to_minutes)

link.compute(d)  # array([ 60, 120, 180])
d.add_component_link(link)
d['minute'] # array([ 60, 120, 180])

Parameters:

• comp_from (ComponentID) – The input ComponentIDs
• comp_to – The target component ID

Pram using:

The translation function which maps data from comp_from to comp_to (optional)

The using function should satisfy:

using(data[comp_from[0]],...,data[comp_from[-1]]) = desired data

Parameters:inverse – The inverse translation function, if exists (optional) Raises:TypeError if input is invalid

Note

Both inverse and using should accept and return numpy arrays

Methods Summary

compute(data[, view])	For a given data set, compute the component comp_to given
get_from_ids()	The list of input ComponentIDs
get_inverse()	The inverse transformation, or None
get_to_id()	The target ComponentID
get_using()	The transformation function
replace_ids(old, new)	Replace all references to an old ComponentID with references
set_from_ids(_from)
set_to_id(to)

Methods Documentation

compute(data, view=None)

For a given data set, compute the component comp_to given the data associated with each comp_from and the using function

Parameters:

• data – The data set to use
• view – Optional view (e.g. slice) through the data to use

Returns:

The data associated with comp_to component

Raises:

InvalidAttribute, if the data set doesn’t have all the ComponentIDs needed for the transformation

get_from_ids()

The list of input ComponentIDs

get_inverse()

The inverse transformation, or None

get_to_id()

The target ComponentID

get_using()

The transformation function

replace_ids(old, new)

Replace all references to an old ComponentID with references to new

Parma old:ComponentID to replace Parameters:new – ComponentID to replace with

set_from_ids(_from)

set_to_id(to)