Feature/eigen3

src/algebra/EigenvalueSolverOptions.hpp

+#ifndef EIGENVALUE_SOLVER_OPTIONS_HPP
+#define EIGENVALUE_SOLVER_OPTIONS_HPP
+
+#include <utils/Exceptions.hpp>
+
+#include <iostream>
+
+enum class ESLibrary : int8_t
+{
+  ES__begin = 0,
+  //
+  eigen3 = ES__begin,
+  slepsc,
+  //
+  ES__end
+};
+
+inline std::string
+name(const ESLibrary library)
+{
+  switch (library) {
+  case ESLibrary::eigen3: {
+    return "Eigen3";
+  }
+  case ESLibrary::slepsc: {
+    return "SLEPSc";
+  }
+  case ESLibrary::ES__end: {
+  }
+  }
+  throw UnexpectedError("Eigenvalue solver library name is not defined!");
+}
+
+template <typename ESEnumType>
+inline ESEnumType
+getESEnumFromName(const std::string& enum_name)
+{
+  using BaseT = std::underlying_type_t<ESEnumType>;
+  for (BaseT enum_value = static_cast<BaseT>(ESEnumType::ES__begin);
+       enum_value < static_cast<BaseT>(ESEnumType::ES__end); ++enum_value) {
+    if (name(ESEnumType{enum_value}) == enum_name) {
+      return ESEnumType{enum_value};
+    }
+  }
+  throw NormalError(std::string{"could not find '"} + enum_name + "' associate type!");
+}
+
+template <typename ESEnumType>
+inline void
+printESEnumListNames(std::ostream& os)
+{
+  using BaseT = std::underlying_type_t<ESEnumType>;
+  for (BaseT enum_value = static_cast<BaseT>(ESEnumType::ES__begin);
+       enum_value < static_cast<BaseT>(ESEnumType::ES__end); ++enum_value) {
+    os << "  - " << name(ESEnumType{enum_value}) << '\n';
+  }
+}
+
+class EigenvalueSolverOptions
+{
+ private:
+  ESLibrary m_library = ESLibrary::slepsc;
+
+ public:
+  static EigenvalueSolverOptions default_options;
+
+  friend std::ostream& operator<<(std::ostream& os, const EigenvalueSolverOptions& options);
+
+  ESLibrary&
+  library()
+  {
+    return m_library;
+  }
+
+  ESLibrary
+  library() const
+  {
+    return m_library;
+  }
+
+  EigenvalueSolverOptions(const EigenvalueSolverOptions&) = default;
+  EigenvalueSolverOptions(EigenvalueSolverOptions&&)      = default;
+
+  EigenvalueSolverOptions()  = default;
+  ~EigenvalueSolverOptions() = default;
+};
+
+inline EigenvalueSolverOptions EigenvalueSolverOptions::default_options;
+
+#endif   // EIGENVALUE_SOLVER_OPTIONS_HPP