multi_sites_combine_charges¶
full name: tenpy.networks.site.multi_sites_combine_charges
parent module:
tenpy.networks.site
type: function
-
tenpy.networks.site.
multi_sites_combine_charges
(sites, same_charges=[])[source]¶ Adjust the charges of the given sites (in place) such that they can be used together.
When we want to contract tensors corresponding to different
Site
instances, these sites need to share a singleChargeInfo
. This function adjusts the charges of these sites such that they can be used together.Deprecated since version 0.7.3: Deprecated in favore of the new, more powerful
set_common_charges()
. Be aware of the slightly different argument structure though, namely that this function keeps charges not included in same_charges, whereas you need to include them explicitly into the new_charges argument of set_common_charges.- Parameters
sites (list of
Site
) – The sites to be combined. Modified in place.same_charges (
[[(int, int|str), (int, int|str), ...], ...]
) – Defines which charges actually are the same, i.e. their quantum numbers are added up. Each charge is specified by a tuple(s, i)= (int, int|str)
, where s gives the index of the site withinsites
and i the index or name of the charge in theChargeInfo
of this site.
- Returns
perms – For each site the permutation performed on the physical leg to sort by charges.
- Return type
list of ndarray
Examples
>>> from tenpy.networks.site import * >>> ferm = SpinHalfFermionSite(cons_N='N', cons_Sz='Sz') >>> spin = SpinSite(1.0, 'Sz') >>> ferm.leg.chinfo is spin.leg.chinfo False >>> print(spin.leg) +1 0 [[-2] 1 [ 0] 2 [ 2]] 3 >>> multi_sites_combine_charges([ferm, spin], same_charges=[[(0, 1), (1, 0)]]) [array([0, 1, 2, 3]), array([0, 1, 2])] >>> # no permutations where needed >>> ferm.leg.chinfo is spin.leg.chinfo True >>> ferm.leg.chinfo.names ['N', '2*Sz'] >>> print(spin.leg) +1 0 [[ 0 -2] 1 [ 0 0] 2 [ 0 2]] 3