From fa3256d56e20e697df0a92c1204aa8705428f15e Mon Sep 17 00:00:00 2001
From: Anton Akhmerov <anton.akhmerov@gmail.com>
Date: Sun, 5 Mar 2017 12:37:21 +0100
Subject: [PATCH] fix lead attachment and add test for previously failing case
Fixes #92.
---
kwant/builder.py | 11 +++++++++--
kwant/tests/test_builder.py | 9 +++++++++
2 files changed, 18 insertions(+), 2 deletions(-)
diff --git a/kwant/builder.py b/kwant/builder.py
index 657a2bf1..68d99b18 100644
--- a/kwant/builder.py
+++ b/kwant/builder.py
@@ -1379,10 +1379,17 @@ class Builder:
if domain < min_dom:
raise ValueError('Builder does not interrupt the lead,'
' this lead cannot be attached.')
- return domain < max_dom + 1
+ return domain <= max_dom + 1
- all_added = self.fill(lead_builder, shape, (max_dom,),
+ # We start flood-fill from the first domain that doesn't belong to the
+ # system (this one is guaranteed to contain a complete unit cell of the
+ # lead). After flood-fill we remove that domain.
+ all_added = self.fill(lead_builder, shape, (max_dom + 1,),
max_sites=float('inf'))
+ to_delete = {site for site in all_added
+ if sym.which(site)[0] == max_dom + 1}
+ all_added = [site for site in all_added if site not in to_delete]
+ del self[to_delete]
# Calculate the interface.
interface = set()
diff --git a/kwant/tests/test_builder.py b/kwant/tests/test_builder.py
index 922f1142..8ffab406 100644
--- a/kwant/tests/test_builder.py
+++ b/kwant/tests/test_builder.py
@@ -772,6 +772,15 @@ def test_attach_lead():
syst.finalized()
+def test_attach_lead_incomplete_unit_cell():
+ lat = kwant.lattice.chain()
+ syst = kwant.Builder()
+ lead = kwant.Builder(kwant.TranslationalSymmetry((2,)))
+ syst[lat(1)] = lead[lat(0)] = lead[lat(1)] = 0
+ lead[lat.neighbors()] = 0
+ assert(len(syst.attach_lead(lead)) == 0)
+
+
def test_neighbors_not_in_single_domain():
sr = builder.Builder()
lead = builder.Builder(VerySimpleSymmetry(-1))
--
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