Merge remote-tracking branch 'upstream/master' into coverage-monitor

Bembel/LinearForm

@@ -26,5 +26,6 @@
 #include "src/LinearForm/DirichletTrace.hpp"
 #include "src/LinearForm/DiscreteLinearForm.hpp"
 #include "src/LinearForm/RotatedTangentialTrace.hpp"
+#include "src/LinearForm/TangentialTrace.hpp"
 
 #endif  // BEMBEL_LINEARFORM_MODULE_

Bembel/src/LinearForm/TangentialTrace.hpp

@@ -0,0 +1,88 @@
+// This file is part of Bembel, the higher order C++ boundary element library.
+//
+// Copyright (C) 2022 see <http://www.bembel.eu>
+//
+// It was written as part of a cooperation of J. Doelz, H. Harbrecht, S. Kurz,
+// M. Multerer, S. Schoeps, and F. Wolf at Technische Universitaet Darmstadt,
+// Universitaet Basel, and Universita della Svizzera italiana, Lugano. This
+// source code is subject to the GNU General Public License version 3 and
+// provided WITHOUT ANY WARRANTY, see <http://www.bembel.eu> for further
+// information.
+#ifndef BEMBEL_SRC_LINEARFORM_TANGENTIALTRACE_HPP_
+#define BEMBEL_SRC_LINEARFORM_TANGENTIALTRACE_HPP_
+
+namespace Bembel {
+
+template <typename Scalar>
+class TangentialTrace;
+
+template <typename ScalarT>
+struct LinearFormTraits<TangentialTrace<ScalarT>> {
+  typedef ScalarT Scalar;
+};
+
+/**
+ *    \ingroup LinearForm
+ *    \brief This class provides a specialization of the linear form required
+ *for the solution of the electric field integral equation.
+ **/
+template <typename Scalar>
+class TangentialTrace : public LinearFormBase<TangentialTrace<Scalar>, Scalar> {
+ public:
+  TangentialTrace() {}
+  void set_function(
+      const std::function<Eigen::Matrix<Scalar, 3, 1>(Eigen::Vector3d)>
+          &function) {
+    function_ = function;
+  }
+  template <class T>
+  void evaluateIntegrand_impl(
+      const T &super_space, const SurfacePoint &p,
+      Eigen::Matrix<Scalar, Eigen::Dynamic, 2> *intval) const {
+    int polynomial_degree = super_space.get_polynomial_degree();
+    int polynomial_degree_plus_one_squared =
+        (polynomial_degree + 1) * (polynomial_degree + 1);
+
+    // get evaluation points on unit square
+    Eigen::Vector2d s = p.segment<2>(0);
+
+    // get quadrature weights
+    double ws = p(2);
+
+    // get points on geometry and tangential derivatives
+    Eigen::Vector3d x_f = p.segment<3>(3);
+    Eigen::Vector3d x_f_dx = p.segment<3>(6);
+    Eigen::Vector3d x_f_dy = p.segment<3>(9);
+
+    // compute surface measures from tangential derivatives
+    Eigen::Vector3d x_n = x_f_dx.cross(x_f_dy).normalized();
+
+    // tangential component + quadrature weights
+    Eigen::Matrix<Scalar, 3, 1> fun_x_f = function_(x_f);
+    Eigen::Matrix<Scalar, 3, 1> tangential_component = fun_x_f.cross(x_n) * ws;
+
+    // extract tangential component
+    Scalar component_x = x_f_dx.dot(tangential_component);
+    Scalar component_y = x_f_dy.dot(tangential_component);
+
+    // evaluate shape functions
+    Eigen::Matrix<Scalar, Eigen::Dynamic, Eigen::Dynamic> phiPhiVec =
+        super_space.basis(s);
+
+    // multiply basis functions with integrand
+    Eigen::Matrix<Scalar, Eigen::Dynamic, 2> phiPhiMat(
+        polynomial_degree_plus_one_squared, 2);
+    phiPhiMat.col(0) = component_x * phiPhiVec;
+    phiPhiMat.col(1) = component_y * phiPhiVec;
+
+    // compute integrals
+    (*intval) += phiPhiMat;
+    return;
+  }
+
+ private:
+  std::function<Eigen::Matrix<Scalar, 3, 1>(Eigen::Vector3d)> function_;
+};
+}  // namespace Bembel
+
+#endif  // BEMBEL_SRC_LINEARFORM_TANGENTIALTRACE_HPP_

tests/CMakeLists.txt

@@ -7,6 +7,7 @@ set(UNITTESTS
 		test_Spline
 		test_Projector
 		test_Glue
+		test_TangentialTrace
 		test_FMMTransferMatrices
 		test_FMMForwardTransformation
 		test_FMMBackwardTransformation

tests/test_TangentialTrace.cpp

@@ -0,0 +1,51 @@
+// This file is part of Bembel, the higher order C++ boundary element library.
+//
+// Copyright (C) 2024 see <http://www.bembel.eu>
+//
+// It was written as part of a cooperation of J. Doelz, H. Harbrecht, S. Kurz,
+// M. Multerer, S. Schoeps, and F. Wolf at Technische Universitaet Darmstadt,
+// Universitaet Basel, and Universita della Svizzera italiana, Lugano. This
+// source code is subject to the GNU General Public License version 3 and
+// provided WITHOUT ANY WARRANTY, see <http://www.bembel.eu> for further
+// information.
+
+#include <Bembel/AnsatzSpace>
+#include <Bembel/Geometry>
+#include <Bembel/LinearForm>
+
+#include "tests/TestGeometries.hpp"
+
+class TestOperatorDivC;
+template <>
+struct Bembel::LinearOperatorTraits<TestOperatorDivC> {
+  typedef Eigen::VectorXd EigenType;
+  typedef Eigen::VectorXd::Scalar Scalar;
+  enum { OperatorOrder = 0, Form = DifferentialForm::DivConforming };
+};
+
+int main() {
+  Test::TestGeometryWriter::writeScreen();
+  Bembel::Geometry geometry("test_Screen.dat");
+
+  const int refinement_level = 0;
+  const int polynomial_degree = 1;
+  Bembel::AnsatzSpace<TestOperatorDivC> ansatz_space(geometry, refinement_level,
+                                                     polynomial_degree);
+
+  std::function<Eigen::Vector3d(Eigen::Vector3d)> fun = [](Eigen::Vector3d in) {
+    return Eigen::Vector3d(in(0), in(1), in(2));
+  };
+
+  Bembel::DiscreteLinearForm<Bembel::TangentialTrace<double>, TestOperatorDivC>
+      disc_lf(ansatz_space);
+  disc_lf.get_linear_form().set_function(fun);
+  disc_lf.compute();
+
+  Eigen::VectorXd ref_sol(4);
+  ref_sol << 0.25, 0.25, -0.25, -0.25;
+
+  BEMBEL_TEST_IF((disc_lf.get_discrete_linear_form() - ref_sol).norm() <
+                 Test::Constants::coefficient_accuracy);
+
+  return 0;
+}