kwant.system.Site

class kwant.system.Site(family, tag, _i_know_what_i_do=False)

Bases: tuple

A site, member of a SiteFamily.

Sites are the vertices of the graph which describes the tight binding system in a Builder.

A site is uniquely identified by its family and its tag.

Parameters

• family (an instance of SiteFamily) – The ‘type’ of the site.

• tag (a hashable python object) – The unique identifier of the site within the site family, typically a vector of integers.

Raises

ValueError – If tag is not a proper tag for family.

Notes

For convenience, family(*tag) can be used instead of Site(family, tag) to create a site.

The parameters of the constructor (see above) are stored as instance variables under the same names. Given a site site, common things to query are thus site.family, site.tag, and site.pos.

Methods

count(value, /)

Return number of occurrences of value.

index(value, start=0, stop=9223372036854775807, /)

Return first index of value.

Raises ValueError if the value is not present.

Attributes

family

The site family to which the site belongs.

pos

Real space position of the site.

This relies on family having a pos method (see SiteFamily).

tag

The tag of the site.