From b8c9d9d640fce9080c4848020e90d2a5201af481 Mon Sep 17 00:00:00 2001
From: Henrik Finsberg <henrikfinsberg@hotmail.com>
Date: Mon, 10 Mar 2025 19:30:46 +0100
Subject: [PATCH] Add script for running stiffness sensitivty

---
 demos/stiffness_sensitivity.py    | 76 +++++++++++++++++++++++++++++++
 src/simcardems/config.py          |  1 +
 src/simcardems/mechanics_model.py |  3 +-
 src/simcardems/models/em_model.py |  1 +
 4 files changed, 80 insertions(+), 1 deletion(-)
 create mode 100644 demos/stiffness_sensitivity.py

diff --git a/demos/stiffness_sensitivity.py b/demos/stiffness_sensitivity.py
new file mode 100644
index 00000000..914083a2
--- /dev/null
+++ b/demos/stiffness_sensitivity.py
@@ -0,0 +1,76 @@
+# # Simple demo
+#
+# In this demo we show the most simple usage of the `simcardems` library using the python API.
+#
+# Import the necessary libraries
+#
+
+from pathlib import Path
+import simcardems
+import matplotlib.pyplot as plt
+import numpy as np
+
+here = Path(__file__).absolute().parent
+geometry_path = here / "geometries/slab.h5"
+geometry_schema_path = here / "geometries/slab.json"
+
+
+def run(outdir: Path, a: float = 2.28):
+    outdir.mkdir(exist_ok=True, parents=True)
+    results_file = outdir.joinpath("results.h5")
+    if results_file.exists():
+        values = np.load(outdir.joinpath("values.npy"), allow_pickle=True).item()
+
+        t = values["time"]
+        lmbda = values["mechanics"]["lambda"]
+        return t, lmbda
+    config = simcardems.Config(
+        outdir=outdir,
+        geometry_path=geometry_path,
+        geometry_schema_path=geometry_schema_path,
+        coupling_type="fully_coupled_ORdmm_Land",
+        T=1000,
+        material_parameter_a=a,
+    )
+    runner = simcardems.Runner(config)
+    runner.solve(T=config.T, save_freq=config.save_freq, show_progress_bar=True)
+
+    loader = simcardems.datacollector.DataLoader(results_file)
+    values = simcardems.postprocess.extract_traces(loader, reduction="center")
+    np.save(outdir.joinpath("values.npy"), values)
+
+    t = values["time"]
+    lmbda = values["mechanics"]["lambda"]
+    fig, ax = plt.subplots()
+    ax.plot(t, lmbda)
+    ax.set_xlabel("Time [ms]")
+    ax.set_ylabel("Lambda")
+    ax.set_title(f"Material parameter a = {a}")
+    fig.savefig(outdir.joinpath(f"lambda_{a}.png"))
+
+    return t, lmbda
+    # simcardems.postprocess.plot_state_traces(outdir.joinpath("results.h5"), "center")
+
+
+def main():
+    outdir = here / "results_stiffness_sensitivity-new"
+    fig, ax = plt.subplots()
+    a_default = 2.28
+    for a in [
+        a_default / 4.0,
+        a_default / 2.0,
+        a_default,
+        a_default * 2.0,
+        a_default * 4.0,
+    ]:
+        t, lmbda = run(outdir=outdir / f"a_{a}", a=a)
+        ax.plot(t, lmbda, label=f"a = {a}")
+    ax.legend()
+    ax.set_xlabel("Time [ms]")
+    ax.set_ylabel("Lambda")
+    ax.set_title("Stiffness sensitivity")
+    fig.savefig(outdir / "stiffness_sensitivity.png")
+
+
+if __name__ == "__main__":
+    main()
diff --git a/src/simcardems/config.py b/src/simcardems/config.py
index 10e4edce..ae5ce306 100644
--- a/src/simcardems/config.py
+++ b/src/simcardems/config.py
@@ -54,6 +54,7 @@ class Config:
         "explicit_ORdmm_Land",
         "pureEP_ORdmm_Land",
     ] = "fully_coupled_ORdmm_Land"
+    material_parameter_a: float = 2.28
 
     def as_dict(self):
         return {k: v for k, v in self.__dict__.items()}
diff --git a/src/simcardems/mechanics_model.py b/src/simcardems/mechanics_model.py
index 482097ab..af7f5ffc 100644
--- a/src/simcardems/mechanics_model.py
+++ b/src/simcardems/mechanics_model.py
@@ -34,6 +34,7 @@ def setup_solver(
     linear_solver="mumps",
     use_custom_newton_solver: bool = config.Config.mechanics_use_custom_newton_solver,
     state_prev=None,
+    material_parameter_a: float = 2.28,
 ):
     """Setup mechanics model with dirichlet boundary conditions or rigid motion."""
 
@@ -43,7 +44,7 @@ def setup_solver(
 
     # Use parameters from Biaxial test in Holzapfel 2019 (Table 1).
     material_parameters = dict(
-        a=2.28,
+        a=material_parameter_a,
         a_f=1.686,
         b=9.726,
         b_f=15.779,
diff --git a/src/simcardems/models/em_model.py b/src/simcardems/models/em_model.py
index f65fa3ea..164760b3 100644
--- a/src/simcardems/models/em_model.py
+++ b/src/simcardems/models/em_model.py
@@ -70,6 +70,7 @@ def setup_EM_model(
         use_custom_newton_solver=config.mechanics_use_custom_newton_solver,
         debug_mode=config.debug_mode,
         ActiveModel=cls_ActiveModel,
+        material_parameter_a=config.material_parameter_a,
     )
     if mech_state_init is not None:
         mech_heart.state.assign(mech_state_init)