# Source code for gpaw.kpoint

```
# Copyright (C) 2003 CAMP
# Please see the accompanying LICENSE file for further information.
"""This module defines a ``KPoint`` class."""
from typing import Optional
from gpaw.projections import Projections
[docs]class KPoint:
"""Class for a single k-point.
The KPoint class takes care of all wave functions for a
certain k-point and a certain spin.
Attributes:
eps_n: float ndarray
Eigenvalues.
f_n: float ndarray
Occupation numbers. The occupation numbers already include the
k-point weight in supercell calculations.
"""
def __init__(self,
weightk: float,
weight: float,
s: int,
k: int,
q: int,
phase_cd=None):
"""Construct k-point object.
Parameters:
weightk:
Weight of this k-point.
weight:
Old confusing weight.
s: int
Spin index: up or down (0 or 1).
k: int
k-point IBZ-index.
q: int
local k-point index.
phase_cd: complex ndarray
Bloch phase-factors for translations - axis c=0,1,2
and direction d=0,1.
"""
self.weightk = weightk # pure k-point weight
self.weight = weight # old confusing weight
self.s = s # spin index
self.k = k # k-point index
self.q = q # local k-point index
self.phase_cd = phase_cd
self.eps_n = None
self.f_n = None
self._projections: Optional[Projections] = None
# Only one of these two will be used:
self.psit = None # UniformGridMatrix/PWExpansionMatrix
self.C_nM = None # LCAO coefficients for wave functions
# LCAO stuff:
self.rho_MM = None
self.S_MM = None
self.T_MM = None
def __repr__(self):
return (f'KPoint(weight={self.weight}, weightk={self.weightk}, '
f's={self.s}, k={self.k}, q={self.q})')
@property
def projections(self) -> Projections:
assert self._projections is not None
return self._projections
@projections.setter
def projections(self, value):
self._projections = value
@property
def P_ani(self):
if self._projections is not None:
return {a: P_ni for a, P_ni in self.projections.items()}
@property
def psit_nG(self):
if self.psit is not None:
return self.psit.array
```