From 900668e6fdf8790485e2412362cb43395812b7ea Mon Sep 17 00:00:00 2001
From: Michael Wimmer <wimmer@lorentz.leidenuniv.nl>
Date: Sun, 1 Sep 2013 21:28:37 +0200
Subject: [PATCH] add test for dtype in setup_linsys
---
kwant/physics/tests/test_leads.py | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)
diff --git a/kwant/physics/tests/test_leads.py b/kwant/physics/tests/test_leads.py
index 399cb62b..21d6f662 100644
--- a/kwant/physics/tests/test_leads.py
+++ b/kwant/physics/tests/test_leads.py
@@ -297,3 +297,30 @@ def test_for_all_evs_equal():
assert modes.vecs.shape == (1, 2)
assert modes.vecslmbdainv.shape == (1, 2)
assert modes.nmodes == 1
+
+
+def test_dtype_linsys():
+ """Test that setup_linsys stays in real arithmetics when possible."""
+ h_cell = np.array([[2.0, -1.0], [-1.0, 2.0]], dtype=np.float64)
+ h_hop = np.array([[0.0],[-1.0]], dtype=np.float64)
+
+ lsys = kwant.physics.leads.setup_linsys(h_cell - 0.3*np.eye(2),
+ h_hop)
+ assert lsys.eigenproblem[0].dtype == np.float64
+
+ lsys = kwant.physics.leads.setup_linsys(h_cell.astype(np.complex128)
+ - 0.3*np.eye(2),
+ h_hop.astype(np.complex128))
+ assert lsys.eigenproblem[0].dtype == np.float64
+
+ # energy=1 is an eigenstate of the isolated cell Hamiltonian,
+ # i.e. a complex self-energy stabilization is necessary
+ lsys = kwant.physics.leads.setup_linsys(h_cell - 1*np.eye(2),
+ h_hop)
+ assert lsys.eigenproblem[0].dtype == np.complex128
+
+ # with complex input, output must be complex, too
+ h_hop = np.array([[0.0],[-1.0 + 0.1j]], dtype=np.complex128)
+ lsys = kwant.physics.leads.setup_linsys(h_cell - 0.3*np.eye(2),
+ h_hop)
+ assert lsys.eigenproblem[0].dtype == np.complex128
--
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