Elasticsearch

Quantity

Class to provide information about available quantities to the transformer.

The elasticsearch transformer will :class:Quantitys to (a) do some semantic checks, (b) map quantities to the underlying elastic index.

Attributes:

Name	Type	Description
name		The name of the quantity as used in the filter expressions.
es_field		The name of the field for this quanity in elastic search, will be name by default.
elastic_mapping_type		A decendent of an elasticsearch_dsl Field that denotes which mapping was used in the elastic search index.
length_quantity		Elasticsearch does not support length of arrays, but we can map fields with array to other fields with ints about the array length. The LENGTH operator will only be supported for quantities with this attribute.
has_only_quantity		Elasticsearch does not support exclusive search on arrays, like a list of chemical elements. But, we can order all elements by atomic number and use a keyword field with all elements to perform this search. This only works for elements (i.e. labels in CHEMICAL_SYMBOLS) and quantities with this attribute.
nested_quantity		To support optimade's 'zipped tuple' feature (e.g. 'elements:elements_ratios HAS "H":>0.33), we use elasticsearch nested objects and nested queries. This quantity will provide the field for the nested object that contains the quantity (and others). The zipped tuples will only work for quantities that share the same nested object quantity.

Transformer (Transformer)

Transformer that transforms v0.10.0 grammer parse trees into queries.

Uses elasticsearch_dsl and will produce a :class:Q instance.

Parameters:

Name	Type	Description	Default
quantities		A list of :class:Quantitys that describe how optimade (and other) quantities are mapped to the elasticsearch index.	required

__default__(self, tree, children, *args, **kwargs) special

Default behavior for rules that only replace one symbol with another

Source code in optimade/filtertransformers/elasticsearch.py

def __default__(self, tree, children, *args, **kwargs):
    """ Default behavior for rules that only replace one symbol with another """
    return children[0]