Move coefficient logic to a function

src/one-body-sample.cc

@@ -139,6 +139,13 @@ template <class FunctionMap> void initPython(FunctionMap &functions) {
       .toC<typename FunctionMap::Base>(functions);
 }
 
+double computeCOF(double mu0, double a, double b, double V0, double L, double V,
+                  double log_state) {
+  double const mu =
+      mu0 + a * std::log(V / V0) + b * (log_state + std::log(V0 / L));
+  return (mu > 0) ? mu : 0;
+}
+
 int main(int argc, char *argv[]) {
   try {
     Dune::Timer timer;
@@ -158,7 +165,7 @@ int main(int argc, char *argv[]) {
 
     auto const E = parset.get<double>("body.E");
     auto const nu = parset.get<double>("body.nu");
-    auto const mu = parset.get<double>("boundary.friction.mu");
+    auto const mu0 = parset.get<double>("boundary.friction.mu0");
     auto const a = parset.get<double>("boundary.friction.a");
     auto const b = parset.get<double>("boundary.friction.b");
     auto const V0 = parset.get<double>("boundary.friction.V0");
@@ -480,8 +487,8 @@ int main(int argc, char *argv[]) {
           state_writer << alpha[i][0] << " ";
           displacement_writer << u[i][0] << " ";
           velocity_writer << ud[i][0] << " ";
-          coefficient_writer << mu + a *std::log(ud[i].two_norm() / V0) +
-                                    b * (alpha[i] + std::log(V0 / L)) << " ";
+          coefficient_writer << computeCOF(mu0, a, b, V0, L, ud[i].two_norm(),
+                                           alpha[i]) << " ";
         }
 
       state_writer << std::endl;

src/one-body-sample.parset

@@ -50,7 +50,7 @@ acceptFactor = 1.0
 requiredResidual = 1e-12
 
 [boundary.friction]
-mu = 0.6
+mu0 = 0.6
 a = 0.010
 b = 0.015
 V0 = 1