From c5963429057111812d5e49ef56695d53cd3a40cc Mon Sep 17 00:00:00 2001
From: Pauli Virtanen <pauli.t.virtanen@jyu.fi>
Date: Wed, 21 Sep 2022 10:27:34 +0300
Subject: [PATCH] tests: fix gauge invariance test
---
tests/test_basic.py | 26 +++++++++++++++++++-------
1 file changed, 19 insertions(+), 7 deletions(-)
diff --git a/tests/test_basic.py b/tests/test_basic.py
index 37c1855..0bd391e 100644
--- a/tests/test_basic.py
+++ b/tests/test_basic.py
@@ -102,7 +102,7 @@ def test_gauge_invariance():
nx, ny, 2, 2
)
s.omega = 0.987
- s.eta = 0.789 * 0
+ s.eta = 0.789
s.D = 1.0
s.Lx = 10
s.Ly = 10
@@ -143,20 +143,32 @@ def test_gauge_invariance():
# Should be invariant to numerical accuracy
assert_allclose(S1, S0, atol=1e-9)
- # Current should be conserved to numerical accuracy
+ # Current should obey a continuity law to numerical accuracy
# due to the gauge symmetry
from usadelndsoc.solver import Result, tr
- res = Result(s, s.omega, Phi2)
+ # Compute current divergence
+ res = Result(s, s.omega, Phi)
t3 = np.diag([1, 1, -1, -1])
J = tr(res.J[i, j] @ t3)
- print(np.where(res.J))
-
div_J_x = J[0] - J[2]
div_J_y = J[1] - J[3]
div_J = div_J_x + div_J_y
- print(J.tolist())
- assert_allclose(div_J, 0, atol=1e-9)
+ # Compute source term (numdiff)
+ Sa = s._core.eval(Phi)
+
+ Phi2 = Phi.copy()
+ ds = 1e-7
+ dW = expm(ds * t3)
+ idW = np.linalg.inv(dW)
+ Phi2[i, j, 0] = dW[:2, :2] @ Phi[i, j, 0] @ idW[2:, 2:]
+ Phi2[i, j, 1] = dW[2:, 2:] @ Phi[i, j, 1] @ idW[:2, :2]
+
+ Sb = s._core.eval(Phi2)
+ dS_ds = (Sb - Sa) / ds / 16
+
+ # They must match
+ assert_allclose(div_J, dS_ds, rtol=1e-6)
--
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