Fixed: CANN material model gives NaN values for a particular activation function choice (SimVascular#410)

divyaadil23 · web-flow · commit 6a68d14b03f0 · 2025-06-25T14:02:15.000-07:00
* Added edge case and removed some commented code

* Added integration test with artery material model on LV geometry
diff --git a/Code/Source/solver/ArtificialNeuralNetMaterial.cpp b/Code/Source/solver/ArtificialNeuralNetMaterial.cpp
@@ -47,9 +47,16 @@ void ArtificialNeuralNetMaterial::uCANN_h0(const double x, const int kf, double
         df = 1;
         ddf = 0;
     } else if (kf == 2) {
-        f = (std::abs(x) + x) / 2;
-        df = 0.5 * (std::abs(x) / x + 1);
-        ddf = 0;
+        if (x == 0) {
+            f = (std::abs(x) + x) / 2;
+            df = 0;
+            ddf = 0;
+        }
+        else {
+            f = (std::abs(x) + x) / 2;
+            df = 0.5 * (std::abs(x) / x + 1);
+            ddf = 0;
+        }
     } else if (kf == 3) {
         f = std::abs(x);
         df = std::abs(x) / x;
diff --git a/Code/Source/solver/distribute.cpp b/Code/Source/solver/distribute.cpp
@@ -1241,21 +1241,7 @@ void dist_mat_consts(const ComMod& com_mod, const CmMod& cm_mod, const cmType& c
       cm.bcast(cm_mod, lStM.paramTable.weights, "paramTable.weights");
     }
 }
-  // cm.bcast(cm_mod, &lStM.paramTable.num_rows);
-
-  // if (lStM.paramTable.num_rows > 0) {
-  //     if (cm.slv(cm_mod))
-  //   {
-  //     lStM.paramTable.invariant_indices.resize(lStM.paramTable.num_rows);
-  //     lStM.paramTable.activation_functions.resize(lStM.paramTable.num_rows,3);
-  //     lStM.paramTable.weights.resize(lStM.paramTable.num_rows,3);
-  //   }
-    
-  //   cm.bcast(cm_mod, lStM.paramTable.invariant_indices);
-  //   cm.bcast(cm_mod, lStM.paramTable.activation_functions, "paramTable.act_func");
-  //   cm.bcast(cm_mod, lStM.paramTable.weights, "paramTable.weights");
-  // }
-
+  
 }
 
 
diff --git a/tests/cases/struct/LV_CANN_artery_material_model/endo_pressure.dat b/tests/cases/struct/LV_CANN_artery_material_model/endo_pressure.dat
@@ -0,0 +1,3 @@
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+size 20865
diff --git a/tests/cases/struct/LV_CANN_artery_material_model/mesh/fibersLongCells.vtu b/tests/cases/struct/LV_CANN_artery_material_model/mesh/fibersLongCells.vtu
@@ -0,0 +1,3 @@
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diff --git a/tests/cases/struct/LV_CANN_artery_material_model/mesh/fibersSheetCells.vtu b/tests/cases/struct/LV_CANN_artery_material_model/mesh/fibersSheetCells.vtu
@@ -0,0 +1,3 @@
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+size 99744
diff --git a/tests/cases/struct/LV_CANN_artery_material_model/mesh/mesh-complete.exterior.vtp b/tests/cases/struct/LV_CANN_artery_material_model/mesh/mesh-complete.exterior.vtp
@@ -0,0 +1,3 @@
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+size 19832
diff --git a/tests/cases/struct/LV_CANN_artery_material_model/mesh/mesh-complete.mesh.vtu b/tests/cases/struct/LV_CANN_artery_material_model/mesh/mesh-complete.mesh.vtu
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diff --git a/tests/cases/struct/LV_CANN_artery_material_model/mesh/mesh-surfaces/endo.vtp b/tests/cases/struct/LV_CANN_artery_material_model/mesh/mesh-surfaces/endo.vtp
@@ -0,0 +1,3 @@
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+size 10038
diff --git a/tests/cases/struct/LV_CANN_artery_material_model/mesh/mesh-surfaces/epi.vtp b/tests/cases/struct/LV_CANN_artery_material_model/mesh/mesh-surfaces/epi.vtp
@@ -0,0 +1,3 @@
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+size 11982
diff --git a/tests/cases/struct/LV_CANN_artery_material_model/mesh/mesh-surfaces/top.vtp b/tests/cases/struct/LV_CANN_artery_material_model/mesh/mesh-surfaces/top.vtp
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
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+size 3940
diff --git a/tests/cases/struct/LV_CANN_artery_material_model/result_001.vtu b/tests/cases/struct/LV_CANN_artery_material_model/result_001.vtu
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:92edf92042952f5bb16fa4eea63a09d215e4bdc8f07b2ab1739822a9eada819a
+size 248065
diff --git a/tests/cases/struct/LV_CANN_artery_material_model/solver.xml b/tests/cases/struct/LV_CANN_artery_material_model/solver.xml
@@ -0,0 +1,127 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<svMultiPhysicsFile version="0.1">
+
+<GeneralSimulationParameters>
+  <Continue_previous_simulation> 0 </Continue_previous_simulation>
+  <Number_of_spatial_dimensions> 3 </Number_of_spatial_dimensions> 
+  <Number_of_time_steps> 1 </Number_of_time_steps> 
+  <Time_step_size> 1e-2 </Time_step_size> 
+  <Spectral_radius_of_infinite_time_step> 0.50 </Spectral_radius_of_infinite_time_step> 
+  <Searched_file_name_to_trigger_stop> STOP_SIM </Searched_file_name_to_trigger_stop> 
+
+  <Save_results_to_VTK_format> 1 </Save_results_to_VTK_format> 
+  <Name_prefix_of_saved_VTK_files> result </Name_prefix_of_saved_VTK_files> 
+  <!-- <Save_results_in_folder> results_svfsiplus </Save_results_in_folder> -->
+  <Increment_in_saving_VTK_files> 1 </Increment_in_saving_VTK_files> 
+  <Start_saving_after_time_step> 1 </Start_saving_after_time_step> 
+
+  <Increment_in_saving_restart_files> 50 </Increment_in_saving_restart_files> 
+  <Convert_BIN_to_VTK_format> 0 </Convert_BIN_to_VTK_format> 
+
+  <Verbose> 1 </Verbose> 
+  <Warning> 1 </Warning> 
+  <Debug> 1 </Debug> 
+
+</GeneralSimulationParameters>
+
+
+<Add_mesh name="msh" > 
+
+  <Mesh_file_path> mesh/mesh-complete.mesh.vtu </Mesh_file_path>
+
+  <Add_face name="endo">
+      <Face_file_path> mesh/mesh-surfaces/endo.vtp </Face_file_path>
+  </Add_face>
+
+  <Add_face name="epi">
+      <Face_file_path> mesh/mesh-surfaces/epi.vtp </Face_file_path>
+  </Add_face>
+
+  <Add_face name="top">
+      <Face_file_path> mesh/mesh-surfaces/top.vtp </Face_file_path>
+  </Add_face>
+
+  <Fiber_direction_file_path> mesh/fibersLongCells.vtu </Fiber_direction_file_path>
+  <Fiber_direction_file_path> mesh/fibersSheetCells.vtu </Fiber_direction_file_path>
+
+  <Mesh_scale_factor> 100.0 </Mesh_scale_factor> <!-- Convert from m to cm -->
+</Add_mesh>
+
+<!-- Using cgs units-->
+<Add_equation type="struct" > 
+
+   <Coupled> true </Coupled>
+   <Min_iterations> 3 </Min_iterations>  
+   <Max_iterations> 20 </Max_iterations> 
+   <Tolerance> 1e-10 </Tolerance> 
+
+   <Density> 1.0 </Density>                           <!-- g/cm^3 -->
+   <Elasticity_modulus> 1.0e6 </Elasticity_modulus>   <!-- dyne/cm^2 -->
+   <Poisson_ratio> 0.483333 </Poisson_ratio>
+    
+    <Constitutive_model type="CANN">
+    		<Add_row row_name="1">
+      		  <Invariant_num> 1 </Invariant_num>
+      		  <Activation_functions> (1,1,1) </Activation_functions>
+      		  <Weights> (1.0,1.0,1.6725e5) </Weights> 
+      		  <!-- mu1 = 33.45 kPa = 3.345e5 dyne/cm2, mu1/2 = 1.6725e5 dyne/cm2 -->
+      		</Add_row>
+    		<Add_row row_name="2">
+      		  <Invariant_num> 1 </Invariant_num>
+      		  <Activation_functions> (1,1,2) </Activation_functions>
+      		  <Weights> (1.0,6.66,2807.807) </Weights> 
+      		  <!-- b = 6.66, a = 3.74 kPa = 3.74e4 dyne/cm2, a/2b = 2807.807 dyne/cm2-->
+      		</Add_row>
+    		<Add_row row_name="3">
+      		  <Invariant_num> 5 </Invariant_num>
+      		  <Activation_functions> (2,2,1) </Activation_functions>
+      		  <Weights> (1.0,1.0,1.085e4) </Weights> 
+      		  <!-- mu5 = 2.17 kPa = 2.17e4 dyne/cm2, mu5/2 = 1.085e4 dyne/cm2-->
+      		</Add_row>
+    		<Add_row row_name="4">
+      		  <Invariant_num> 9 </Invariant_num>
+      		  <Activation_functions> (2,2,1) </Activation_functions>
+      		  <Weights> (1.0,1.0,1.085e4) </Weights> 
+      		  <!-- mu5 = 2.17 kPa = 2.17e4 dyne/cm2, mu5/2 = 1.085e4 dyne/cm2-->
+      		</Add_row>
+   	</Constitutive_model>
+
+   <Dilational_penalty_model> ST91 </Dilational_penalty_model>
+   <Penalty_parameter>1.0e7</Penalty_parameter>
+
+    <Output type="Spatial" >
+     <Displacement> true </Displacement>
+     <Velocity> true </Velocity>
+     <Jacobian> true </Jacobian>
+     <Stress> true </Stress>
+     <Strain> true </Strain>
+     <Cauchy_stress> true </Cauchy_stress>
+     <Def_grad> true </Def_grad>
+     <VonMises_stress> true </VonMises_stress>
+   </Output>
+
+   <LS type="GMRES" >
+      <Linear_algebra type="fsils" >
+         <Preconditioner> fsils </Preconditioner>
+      </Linear_algebra>
+      <Tolerance> 1e-16 </Tolerance>
+      <Max_iterations> 1000 </Max_iterations> 
+      <Krylov_space_dimension> 50 </Krylov_space_dimension>
+   </LS>
+
+   <Add_BC name="top" > 
+      <Type> Dirichlet </Type> 
+      <Value> 0.0 </Value>
+   </Add_BC> 
+
+   <Add_BC name="endo" > 
+      <Type> Neu </Type> 
+      <Time_dependence> Unsteady </Time_dependence> 
+      <Temporal_values_file_path> endo_pressure.dat </Temporal_values_file_path> 
+      <Ramp_function> false </Ramp_function> 
+      <Follower_pressure_load> true </Follower_pressure_load> 
+   </Add_BC> 
+
+</Add_equation>
+
+</svMultiPhysicsFile>
diff --git a/tests/test_struct.py b/tests/test_struct.py
@@ -32,6 +32,10 @@ def test_LV_HolzapfelOgden_passive_CANN(n_proc):
     test_folder = "LV_HolzapfelOgden_passive_CANN"
     run_with_reference(base_folder, test_folder, fields, n_proc)
 
+def test_LV_CANN_artery_material_model(n_proc):
+    test_folder = "LV_CANN_artery_material_model"
+    run_with_reference(base_folder, test_folder, fields, n_proc)
+
 def test_LV_HolzapfelOgdenModifiedAnisotropy_passive(n_proc):
     test_folder = "LV_HolzapfelOgdenModifiedAnisotropy_passive"
     run_with_reference(base_folder, test_folder, fields, n_proc)

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