UniqueValuesMapping

class ase2sprkkr.common.unique_values.UniqueValuesMapping(mapping, value_to_class_id=None)

A class, that can map a collection of (possible non-unique) values to a set of unique identifiers. It effectively makes the classes of equivalence between indexes of the input array.

The instances of the class can be merged to distinct the values, that are the same according to one criterion, but distinct on the other.

>>> UniqueValuesMapping.from_values([1,4,1]).mapping
array([1, 2, 1])
>>> UniqueValuesMapping.from_values([int, int, str]).mapping
array([1, 1, 2])
>>> UniqueValuesMapping.from_values([1,4,1]).value_to_class_id
{1: 1, 4: 2}
>>> UniqueValuesMapping.from_values([1,4,1,1]).merge([1,1,2,1]).mapping
array([1, 2, 3, 1])

Class hierarchy

Constructor

Parameters

• mapping (List) –

• value_to_class_id (Dict) –

__init__(mapping, value_to_class_id=None)

Parameters

• mapping (Union[np.ndarray, list]) – Array of equivalence class members members[id] = <eq class id>

• reverse (dict) – Mapping { value: <eq class id> }

• value_to_class_id (Dict) –

mapping

Map from <object index> to <object equivalence class id>.

value_to_class_id

Map from <object> to <object equivalence class id>. If two mappings are merged, this attribute is not available.

indexes(start_from=0)

Returns the dictionary that maps equivalence class id to the list of class members indexes.

Parameters

• start_from (int) – The indexes are by default zero-based, however they can start with the given number (typically with 1).

• ..doctest:: –

  >>> UniqueValuesMapping([1,4,1]).indexes()
  {1: [0, 2], 4: [1]}
  >>> UniqueValuesMapping([1,4,1]).indexes(start_from = 1)
  {1: [1, 3], 4: [2]}
  

iter_unique()

len_of_unique()

static from_values(values, length=None)

Create equivalence-classes mapping. Unlike the constructor, this method tags the values by integers and also compute the reverse (value to equivalence class) mapping.

values: iterable

Values to find the equivalence classes

length: int

Length of values - provide it, if len(values) is not available

Parameters

length (Optional[int]) –

static _create_mapping(values, length=None, start_from=1)

merge(other)

Merge two sets. Resulting UniqueValues uses integers as keys

is_equivalent_to(mapping)

Return, whether the mapping is equal to given another mapping, regardless the actual “names” of the equivalence classes.

Parameters

• mapping (Union[UniqueValuesMapping, Iterable]) – The other mapping can be given either by instance of this class, or just by any iterable (that returns equivalence class names for the items)

• doctest:: (..) –

  >>> UniqueValuesMapping([1,4,1]).is_equivalent_to([0,1,0])
  True
  >>> UniqueValuesMapping([1,4,1]).is_equivalent_to([0,0,0])
  False
  >>> UniqueValuesMapping([1,4,1]).is_equivalent_to([0,1,1])
  False
  >>> UniqueValuesMapping([1,4,1]).is_equivalent_to([5,3,5])
  True
  >>> UniqueValuesMapping([1,4,1]).is_equivalent_to(UniqueValuesMapping.from_values([2,5,2]))
  True
  

Return type

bool

static are_equivalent(a, b)

Return, whether the two mappings are equal, regardless the actual “names” of the equivalence classes.

See is_equivalent

Parameters

• a (Union[UniqueValuesMapping, Iterable]) –

• b (Union[UniqueValuesMapping, Iterable]) –

Return type

bool

normalize(start_from=1, strict=False)

Replace the names of equivalent classes by the integers.

Parameters

• strict (bool) – If True, the resulting integer names will be from range (start_from)..(n+start_from-1), where n is the number of equivalence classes. If False and the names are already integers in a numpy array, do nothing.

• start_from – Number the equivalent classes starting from.

Returns

• unique_values_mapping – Return self.

• .. doctest:: – >>> UniqueValuesMapping.from_values([(0,2),(0,3),(0,2)]).normalize().mapping array([1, 2, 1]) >>> UniqueValuesMapping.from_values([(0,2),(0,3),(0,2)]).normalize().value_to_class_id[(0,3)] 2 >>> UniqueValuesMapping.from_values([(0,2),(0,3),(0,2)]).normalize(start_from=0).mapping array([0, 1, 0])