feat(fem-and-beam-kernel): step 1 — dof-manager

include/fesa/fem/dof_manager.hpp

@@ -0,0 +1,52 @@
+#pragma once
+
+#include <array>
+#include <cstddef>
+#include <cstdint>
+#include <map>
+#include <optional>
+#include <span>
+#include <vector>
+
+#include <fesa/model/domain.hpp>
+
+namespace fesa {
+
+enum class NodeDof : std::uint8_t {
+    ux,
+    uy,
+    uz,
+    rx,
+    ry,
+    rz,
+};
+
+struct DofAddress final {
+    NodeId node;
+    NodeDof dof;
+};
+
+class DofManager final {
+public:
+    [[nodiscard]] static DofManager build(const Domain& domain);
+
+    [[nodiscard]] std::size_t full_dof_count() const noexcept;
+    [[nodiscard]] std::size_t free_equation_count() const noexcept;
+    [[nodiscard]] std::optional<std::size_t> equation(
+        DofAddress address) const;
+    [[nodiscard]] std::array<std::size_t, 12> element_full_dofs(
+        const BeamElement& element) const;
+    [[nodiscard]] std::vector<double> reconstruct_full(
+        std::span<const double> reduced) const;
+
+private:
+    [[nodiscard]] std::size_t full_dof(DofAddress address) const;
+    [[nodiscard]] std::size_t node_full_dof_base(NodeId node) const;
+
+    std::map<std::int64_t, std::size_t> node_full_dof_bases_;
+    std::vector<std::optional<std::size_t>> equations_;
+    std::vector<double> prescribed_values_;
+    std::size_t free_equation_count_ = 0;
+};
+
+}  // namespace fesa