From 972ffd13c0e73a9c98f1ff3097a9610d41835a04 Mon Sep 17 00:00:00 2001
From: Anton Akhmerov <anton.akhmerov@gmail.com>
Date: Thu, 21 Feb 2013 22:35:55 -0500
Subject: [PATCH] make TranslationalSymmetry.periods correct for reversed
symmetries
---
kwant/lattice.py | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/kwant/lattice.py b/kwant/lattice.py
index c0069ad1..376087f6 100644
--- a/kwant/lattice.py
+++ b/kwant/lattice.py
@@ -233,6 +233,7 @@ class TranslationalSymmetry(builder.Symmetry):
"""
def __init__(self, *periods):
self.periods = ta.array(periods)
+ self._periods = self.periods
if self.periods.ndim != 2:
# TODO: remove the second part of the following message once
# everybody got used to it.
@@ -274,11 +275,11 @@ class TranslationalSymmetry(builder.Symmetry):
raise KeyError('Group already processed, delete it from '
'site_group_data first.')
inv = np.linalg.pinv(gr.prim_vecs)
- bravais_periods = [np.dot(i, inv) for i in self.periods]
+ bravais_periods = [np.dot(i, inv) for i in self._periods]
if not np.allclose(bravais_periods, np.round(bravais_periods),
rtol=0, atol=1e-8) or \
not np.allclose([gr.vec(i) for i in bravais_periods],
- self.periods):
+ self._periods):
msg = 'Site group {0} does not have commensurate periods with ' +\
'symmetry {1}.'
raise ValueError(msg.format(gr, self))
@@ -366,9 +367,10 @@ class TranslationalSymmetry(builder.Symmetry):
The resulting symmetry has all the period vectors opposite to the
original and an identical fundamental domain.
"""
- result = TranslationalSymmetry(*self.periods)
+ result = TranslationalSymmetry(*self._periods)
result.site_group_data = self.site_group_data
result.is_reversed = not self.is_reversed
+ result.periods = -self.periods
return result
--
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