From ad869e41daf6428207a0b7df00e9c52194dabd91 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Felix=20K=C3=B6hler?=
 <27728103+Ceyron@users.noreply.github.com>
Date: Tue, 22 Oct 2024 14:34:20 +0200
Subject: [PATCH] Conservative KS should use conservative convection (#50)

* Conservative KS should use conservative convection

* Adapt tests
---
 exponax/stepper/_kuramoto_sivashinsky.py |  2 +-
 tests/test_builtin_solvers.py            | 12 +++++++++++-
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/exponax/stepper/_kuramoto_sivashinsky.py b/exponax/stepper/_kuramoto_sivashinsky.py
index 7acabbf..b4f84c4 100644
--- a/exponax/stepper/_kuramoto_sivashinsky.py
+++ b/exponax/stepper/_kuramoto_sivashinsky.py
@@ -190,7 +190,7 @@ def __init__(
         second_order_diffusivity: float = 1.0,
         fourth_order_diffusivity: float = 1.0,
         single_channel: bool = False,
-        conservative: bool = False,
+        conservative: bool = True,
         dealiasing_fraction: float = 2 / 3,
         order: int = 2,
         num_circle_points: int = 16,
diff --git a/tests/test_builtin_solvers.py b/tests/test_builtin_solvers.py
index dc95e43..1c1acd4 100644
--- a/tests/test_builtin_solvers.py
+++ b/tests/test_builtin_solvers.py
@@ -117,18 +117,20 @@ def test_specific_stepper_to_general_linear_stepper(
 
 
 @pytest.mark.parametrize(
-    "specific_stepper,general_stepper_scale,general_stepper_coefficients",
+    "specific_stepper,general_stepper_scale,general_stepper_coefficients,conservative",
     [
         # Linear problems
         (
             ex.stepper.Advection(1, 3.0, 50, 0.1, velocity=1.0),
             0.0,
             [0.0, -1.0],
+            False,
         ),
         (
             ex.stepper.Diffusion(1, 3.0, 50, 0.1, diffusivity=0.01),
             0.0,
             [0.0, 0.0, 0.01],
+            False,
         ),
         (
             ex.stepper.AdvectionDiffusion(
@@ -136,22 +138,26 @@ def test_specific_stepper_to_general_linear_stepper(
             ),
             0.0,
             [0.0, -1.0, 0.01],
+            False,
         ),
         (
             ex.stepper.Dispersion(1, 3.0, 50, 0.1, dispersivity=0.0001),
             0.0,
             [0.0, 0.0, 0.0, 0.0001],
+            False,
         ),
         (
             ex.stepper.HyperDiffusion(1, 3.0, 50, 0.1, hyper_diffusivity=0.00001),
             0.0,
             [0.0, 0.0, 0.0, 0.0, -0.00001],
+            False,
         ),
         # nonlinear problems
         (
             ex.stepper.Burgers(1, 3.0, 50, 0.1, diffusivity=0.05, convection_scale=1.0),
             1.0,
             [0.0, 0.0, 0.05],
+            False,
         ),
         (
             ex.stepper.KortewegDeVries(
@@ -159,6 +165,7 @@ def test_specific_stepper_to_general_linear_stepper(
             ),
             -6.0,
             [0.0, 0.0, 0.0, -1.0, -0.01],
+            False,
         ),
         (
             ex.stepper.KuramotoSivashinskyConservative(
@@ -172,6 +179,7 @@ def test_specific_stepper_to_general_linear_stepper(
             ),
             1.0,
             [0.0, 0.0, -1.0, 0.0, -1.0],
+            True,
         ),
     ],
 )
@@ -179,6 +187,7 @@ def test_specific_stepper_to_general_convection_stepper(
     specific_stepper,
     general_stepper_scale,
     general_stepper_coefficients,
+    conservative,
 ):
     num_spatial_dims = specific_stepper.num_spatial_dims
     domain_extent = specific_stepper.domain_extent
@@ -197,6 +206,7 @@ def test_specific_stepper_to_general_convection_stepper(
         dt,
         coefficients=general_stepper_coefficients,
         convection_scale=general_stepper_scale,
+        conservative=conservative,
     )
 
     specific_pred = specific_stepper(u_0)