refactor: extract assembly analysis workflow

include/fesa/Assembly/AssemblySystem.hpp

@@ -0,0 +1,168 @@
+#pragma once
+
+#include "fesa/Core/Core.hpp"
+#include "fesa/Element/Element.hpp"
+#include "fesa/Load/Load.hpp"
+#include "fesa/Math/Math.hpp"
+#include "fesa/Property/Property.hpp"
+#include "fesa/Util/Diagnostics.hpp"
+
+#include <array>
+#include <set>
+#include <stdexcept>
+#include <utility>
+#include <vector>
+
+namespace fesa {
+
+inline SparsePattern buildReducedSparsePattern(const Domain& domain, const DofManager& dofs) {
+  SparsePattern pattern;
+  pattern.equation_count = dofs.freeDofCount();
+  std::set<std::pair<EquationId, EquationId>> ordered_entries;
+  for (const auto& [element_id, element] : domain.elements) {
+    (void)element_id;
+    const auto equations = dofs.elementEquationIds(element);
+    for (EquationId row : equations) {
+      if (row < 0) {
+        continue;
+      }
+      for (EquationId col : equations) {
+        if (col < 0) {
+          continue;
+        }
+        ordered_entries.insert({row, col});
+      }
+    }
+  }
+  pattern.entries.reserve(ordered_entries.size());
+  for (const auto& entry : ordered_entries) {
+    pattern.entries.push_back({entry.first, entry.second});
+  }
+  return pattern;
+}
+
+inline std::vector<Real> recoverFullReaction(const DenseMatrix& k_full,
+                                             const std::vector<Real>& u_full,
+                                             const std::vector<Real>& f_full) {
+  if (k_full.rows() != k_full.cols() || static_cast<LocalIndex>(u_full.size()) != k_full.cols() ||
+      static_cast<LocalIndex>(f_full.size()) != k_full.rows()) {
+    throw std::runtime_error("full reaction size mismatch");
+  }
+  std::vector<Real> reaction = k_full.multiply(u_full);
+  for (std::size_t i = 0; i < reaction.size(); ++i) {
+    reaction[i] -= f_full[i];
+  }
+  return reaction;
+}
+
+struct AssemblyResult {
+  DenseMatrix k_full;
+  std::vector<Real> f_full;
+  SparsePattern reduced_pattern;
+  std::vector<Diagnostic> diagnostics;
+
+  bool ok() const {
+    return !hasError(diagnostics);
+  }
+};
+
+struct ReducedSystem {
+  DenseMatrix k;
+  std::vector<Real> f;
+  std::vector<LocalIndex> free_full_indices;
+  std::vector<Diagnostic> diagnostics;
+
+  bool ok() const {
+    return !hasError(diagnostics);
+  }
+};
+
+inline AssemblyResult assembleSystem(const Domain& domain, const DofManager& dofs, ElementStiffnessOptions options = {}) {
+  AssemblyResult result;
+  result.k_full = DenseMatrix(dofs.fullDofCount(), dofs.fullDofCount());
+  result.f_full = std::vector<Real>(static_cast<std::size_t>(dofs.fullDofCount()), 0.0);
+  result.reduced_pattern = buildReducedSparsePattern(domain, dofs);
+  if (dofs.freeDofCount() > 0 && result.reduced_pattern.nonzeroCount() == 0) {
+    result.diagnostics.push_back(makeDiagnostic(Severity::Error, "FESA-SINGULAR-SPARSE-PATTERN",
+                                                "Reduced sparse pattern has no stiffness entries", "assembly"));
+  }
+  for (const auto& [element_id, element] : domain.elements) {
+    const ShellSection* section = shellSectionForElement(domain, element_id);
+    if (section == nullptr) {
+      result.diagnostics.push_back(
+          {Severity::Error, "FESA-ASSEMBLY-MISSING-PROPERTY", "Element has no shell section", {}});
+      continue;
+    }
+    const auto material_it = domain.materials.find(Domain::key(section->material));
+    if (material_it == domain.materials.end()) {
+      result.diagnostics.push_back(
+          {Severity::Error, "FESA-ASSEMBLY-MISSING-MATERIAL", "Element material is missing", {}});
+      continue;
+    }
+    std::array<Vec3, 4> coordinates{};
+    for (std::size_t i = 0; i < 4; ++i) {
+      coordinates[i] = domain.nodes.at(element.node_ids[i]).coordinates;
+    }
+    const auto stiffness = mitc4ElementStiffness(coordinates, material_it->second.elastic_modulus,
+                                                 material_it->second.poisson_ratio, section->thickness, options);
+    result.diagnostics.insert(result.diagnostics.end(), stiffness.diagnostics.begin(), stiffness.diagnostics.end());
+    if (!stiffness.ok()) {
+      continue;
+    }
+    const auto element_full_indices = dofs.elementFullDofIndices(element);
+    for (LocalIndex a = 0; a < 24; ++a) {
+      const LocalIndex ia = element_full_indices[static_cast<std::size_t>(a)];
+      for (LocalIndex b = 0; b < 24; ++b) {
+        const LocalIndex ib = element_full_indices[static_cast<std::size_t>(b)];
+        result.k_full.add(ia, ib, stiffness.global(a, b));
+      }
+    }
+  }
+  for (const NodalLoad& load : domain.loads) {
+    const auto dof = dofFromAbaqus(load.dof);
+    if (!dof) {
+      result.diagnostics.push_back(makeDiagnostic(Severity::Error, "FESA-ASSEMBLY-LOAD-DOF",
+                                                  "Nodal load references an invalid DOF", "cload"));
+      continue;
+    }
+    for (GlobalId node_id : resolveNodeTarget(domain, load.target, &result.diagnostics)) {
+      result.f_full[static_cast<std::size_t>(dofs.fullIndex(node_id, *dof))] += load.magnitude;
+    }
+  }
+  return result;
+}
+
+inline ReducedSystem projectToReducedSystem(const AssemblyResult& assembly, const DofManager& dofs) {
+  ReducedSystem result;
+  result.k = DenseMatrix(dofs.freeDofCount(), dofs.freeDofCount());
+  result.f = std::vector<Real>(static_cast<std::size_t>(dofs.freeDofCount()), 0.0);
+  result.free_full_indices = dofs.freeFullIndices();
+  if (assembly.k_full.rows() != assembly.k_full.cols() || assembly.k_full.rows() != dofs.fullDofCount() ||
+      static_cast<LocalIndex>(assembly.f_full.size()) != dofs.fullDofCount()) {
+    result.diagnostics.push_back(makeDiagnostic(Severity::Error, "FESA-ASSEMBLY-SIZE",
+                                                "Full-space stiffness/load sizes do not match DofManager", "assembly"));
+    return result;
+  }
+  if (dofs.freeDofCount() == 0) {
+    result.diagnostics.push_back(makeDiagnostic(Severity::Error, "FESA-SINGULAR-NO-FREE-DOFS",
+                                                "No free DOFs exist after applying constraints", "dof"));
+    return result;
+  }
+  if (assembly.reduced_pattern.equation_count != dofs.freeDofCount() || assembly.reduced_pattern.nonzeroCount() == 0) {
+    result.diagnostics.push_back(makeDiagnostic(Severity::Error, "FESA-SINGULAR-SPARSE-PATTERN",
+                                                "Reduced sparse pattern is empty or inconsistent with free DOFs",
+                                                "assembly"));
+    return result;
+  }
+  for (LocalIndex i = 0; i < dofs.freeDofCount(); ++i) {
+    const LocalIndex full_i = dofs.freeFullIndices()[static_cast<std::size_t>(i)];
+    result.f[static_cast<std::size_t>(i)] = assembly.f_full[static_cast<std::size_t>(full_i)];
+    for (LocalIndex j = 0; j < dofs.freeDofCount(); ++j) {
+      const LocalIndex full_j = dofs.freeFullIndices()[static_cast<std::size_t>(j)];
+      result.k(i, j) = assembly.k_full(full_i, full_j);
+    }
+  }
+  return result;
+}
+
+}  // namespace fesa