# Linear Static 3D Euler Beam Implementation Report

## Metadata

- feature_id: `linear-static-3d-euler-beam`
- source_plan: `docs/implementation-plans/linear-static-3d-euler-beam.md`
- source_design: `docs/superpowers/specs/2026-08-08-linear-static-3d-euler-beam-design.md`
- status: `in-progress`
- owner_agent: `implementation-agent`
- validation_environment: `Windows, MSVC 19.51.36252, Visual Studio 18 2026, x64 Debug`
- report_started: `2026-08-09`

## Step 7 — cmake-test-foundation

- task_id: `TASK-07`
- status: `completed`
- changed_files: `CMakeLists.txt`, `cmake/FesaDependencies.cmake`,
  `include/fesa/build_info.hpp`, `src/fesa/build_info.cpp`,
  `src/fesa/CMakeLists.txt`, `tests/CMakeLists.txt`,
  `tests/unit/build_info_test.cpp`,
  `docs/implementation-plans/linear-static-3d-euler-beam-implementation-report.md`
- requirement_ids: `FESA-REQ-LS3DEB-030`, `FESA-REQ-LS3DEB-034`
- test_ids: `T07-BUILD-001`, `T07-BUILD-002`

| stage | exact command | exit_code | expected_or_observed_result | evidence_tail |
| --- | --- | ---: | --- | --- |
| RED | Temporarily move `include/fesa/build_info.hpp` to `.harness/build_info.hpp.red-backup`; run `cmake --build .harness/build --config Debug --target fesa_unit_tests`; restore the header in `finally` | 1 | Build fails because the public API is unavailable | `build_info.cpp(1,10): error C1083: 'fesa/build_info.hpp': No such file or directory` |
| GREEN | `cmake --build .harness/build --config Debug --target fesa_tests`; `ctest --test-dir .harness/build -C Debug -R BuildInfo --output-on-failure` | 0 | Foundation target builds and both named BuildInfo tests pass | `BuildInfo.VersionIsStableAndNonEmpty` and `BuildInfo.PublicHeaderHasNoBackendDependency`: 2/2 passed |
| VERIFY-configure | `cmake -S . -B .harness/build -A x64 -DFESA_GTEST_SOURCE_DIR=C:/git/googletest "-DMKL_DIR=C:/Program Files (x86)/Intel/oneAPI/mkl/2026.1/lib/cmake/mkl" "-DTBB_DIR=C:/Program Files (x86)/Intel/oneAPI/tbb/2023.1/lib/cmake/tbb" "-DHDF5_DIR=C:/Program Files/HDF_Group/HDF5/2.1.1/cmake"` | 0 | MSVC x64 Debug build tree generated and dependencies resolved | Visual Studio 18 2026; MSVC 19.51.36252; MKL 2026.1; TBB and HDF5 CONFIG packages resolved |
| VERIFY-build | `cmake --build .harness/build --config Debug` | 0 | FESA and GoogleTest targets build without FESA warnings | `fesa_solver.lib` and `fesa_unit_tests.exe` built; no warning emitted under FESA `/W4 /WX` |
| VERIFY-discovery | `ctest --test-dir .harness/build -C Debug --show-only=json-v1` | 0 | CTest discovers at least one test | 2 tests discovered, both carrying `linear-static-3d-euler-beam` and `unit` labels |
| VERIFY-full | `ctest --test-dir .harness/build -C Debug --output-on-failure` | 0 | Full suite has zero failures | 2/2 tests passed |

- contract_checks: GoogleTest revision
  `04ee1b4f2aefdffb0135d7cf2a2c519fe50dabe4`; no default
  `C:/git/googletest` path in production CMake; `/W4 /WX` is private to
  `fesa_solver`; public BuildInfo header exposes only `std::string_view`.
- generated_evidence: `.harness/build/src/fesa/Debug/fesa_solver.lib`,
  `.harness/build/tests/Debug/fesa_unit_tests.exe`
- environment_note: Native Codex Windows workspace sandboxes stalled in the
  CMake compiler-id `cl.exe` child process. The identical approved configure,
  build, and CTest commands were therefore executed by the root session's
  authorized unrestricted shell; the same configure completed in 7.9 seconds.
- reference_diff: unchanged
- handoff: `fesa_solver`, `fesa_unit_tests`, `fesa_tests`, normalized
  `Fesa::MKL`, `Fesa::TBB`, `Fesa::HDF5`, and `solverVersion()` are available
  to Step 8.

## Step 8 — core-diagnostics

- task_id: `TASK-08`
- status: `completed`
- changed_files: `include/fesa/core/source_identity.hpp`,
  `include/fesa/core/diagnostic.hpp`, `include/fesa/core/status.hpp`,
  `src/fesa/core/diagnostic.cpp`, `src/fesa/core/status.cpp`,
  `src/fesa/CMakeLists.txt`, `tests/CMakeLists.txt`,
  `tests/unit/core/source_identity_test.cpp`,
  `tests/unit/core/diagnostic_test.cpp`, `tests/unit/core/status_test.cpp`,
  `docs/implementation-plans/linear-static-3d-euler-beam-implementation-report.md`
- requirement_ids: `FESA-REQ-LS3DEB-033`, `FESA-REQ-LS3DEB-034`
- test_ids: `T08-CORE-001`, `T08-CORE-002`, `T08-CORE-003`

| stage | exact command | exit_code | expected_or_observed_result | evidence_tail |
| --- | --- | ---: | --- | --- |
| RED | `cmake --build .harness/build --config Debug --target fesa_tests` | 1 | Tests are registered before production and fail for the three missing core headers | MSVC C1083 for `fesa/core/diagnostic.hpp`, `fesa/core/source_identity.hpp`, and `fesa/core/status.hpp` |
| GREEN-build | `cmake --build .harness/build --config Debug --target fesa_tests` | 0 | Minimal core implementation and all test translation units build | `diagnostic.cpp`, `status.cpp`, and three core tests compile; `fesa_unit_tests.exe` links |
| GREEN-test | `ctest --test-dir .harness/build -C Debug -R CoreDiagnostics --output-on-failure` | 0 | Identity, deterministic ordering, and Result exclusivity pass | 3/3 `CoreDiagnostics` tests passed |
| VERIFY-configure | `cmake -S . -B .harness/build -A x64 -DFESA_GTEST_SOURCE_DIR=C:/git/googletest "-DMKL_DIR=C:/Program Files (x86)/Intel/oneAPI/mkl/2026.1/lib/cmake/mkl" "-DTBB_DIR=C:/Program Files (x86)/Intel/oneAPI/tbb/2023.1/lib/cmake/tbb" "-DHDF5_DIR=C:/Program Files/HDF_Group/HDF5/2.1.1/cmake"` | 0 | Approved MSVC x64 build tree regenerates with normalized dependencies | Configure and generate completed; MKL 2026.1 resolved |
| VERIFY-build | `cmake --build .harness/build --config Debug` | 0 | Full Debug build passes without a new FESA warning | `fesa_solver.lib` and `fesa_unit_tests.exe` built under `/W4 /WX` |
| VERIFY-targeted | `ctest --test-dir .harness/build -C Debug -R CoreDiagnostics --output-on-failure` | 0 | Focused Step 8 suite remains green | 3/3 tests passed |
| VERIFY-discovery | `ctest --test-dir .harness/build -C Debug --show-only=json-v1` | 0 | CTest discovers the existing and new named tests | 5 tests discovered with feature and unit labels |
| VERIFY-full | `ctest --test-dir .harness/build -C Debug --output-on-failure` | 0 | Full accumulated C++ suite has zero failures | 5/5 tests passed |
| VERIFY-harness | `uv run --with pytest python -m pytest -v -rs` | 0 | Harness regression suite remains green | 4/4 tests passed |

- contract_checks: `SourceEntityId` preserves numeric and raw label forms;
  `sortDiagnostics()` applies the fixed file/line/keyword/entity/code tuple with
  stable discovery-order ties; `Status` owns sorted diagnostics and optional
  failure category; `Result<T>` owns either a value or failed status and rejects
  both failed value access and construction from an OK status. Core public
  headers include only FESA core or C++ standard-library headers; no
  MKL/TBB/HDF5 names are present.
- generated_evidence: `.harness/build/src/fesa/Debug/fesa_solver.lib`,
  `.harness/build/tests/Debug/fesa_unit_tests.exe`
- reference_diff: unchanged
- handoff: `SourceLocation`, `SourceEntityId`, `Diagnostic`, deterministic
  diagnostic sorting, `FailureCategory`, `Status`, and `Result<T>` are available
  to Step 9 and later parser/model/solver tasks.

## Step 9 — dense-math-adapters

- task_id: `TASK-09`
- status: `completed`
- changed_files: `include/fesa/math/vector.hpp`,
  `include/fesa/math/matrix.hpp`, `src/fesa/math/vector.cpp`,
  `src/fesa/math/matrix.cpp`, `tests/unit/math/vector_test.cpp`,
  `tests/unit/math/matrix_test.cpp`, `src/fesa/CMakeLists.txt`,
  `tests/CMakeLists.txt`,
  `docs/implementation-plans/linear-static-3d-euler-beam-implementation-report.md`,
  `phases/linear-static-3d-euler-beam/index.json`
- requirement_ids: `FESA-REQ-LS3DEB-025`, `FESA-REQ-LS3DEB-034`
- test_ids: `T09-DENSE-001`, `T09-DENSE-002`

| stage | exact command | exit_code | expected_or_observed_result | evidence_tail |
| --- | --- | ---: | --- | --- |
| RED | `cmake --build .harness/build --config Debug --target fesa_tests`; `ctest --test-dir .harness/build -C Debug -R DenseMath --output-on-failure` | 1 | Both planned tests are registered before production and the build fails for the missing dense-math API | MSVC C1083 for `fesa/math/matrix.hpp` and `fesa/math/vector.hpp`; DenseMath discovery is unavailable until the test executable builds |
| GREEN-build | `cmake --build .harness/build --config Debug --target fesa_tests` | 0 | Minimal dense adapters, tests, and runtime staging compile, link, and complete GoogleTest discovery | `matrix.cpp`, `vector.cpp`, both math tests, `fesa_solver.lib`, and `fesa_unit_tests.exe` built; no FESA warning under `/W4 /WX` |
| GREEN-test | `ctest --test-dir .harness/build -C Debug -R DenseMath --output-on-failure` | 0 | Storage/ownership/checking and row-major BLAS contracts pass | 2/2 DenseMath tests passed |
| VERIFY-configure | `cmake -S . -B .harness/build -A x64 -DFESA_GTEST_SOURCE_DIR=C:/git/googletest "-DMKL_DIR=C:/Program Files (x86)/Intel/oneAPI/mkl/2026.1/lib/cmake/mkl" "-DTBB_DIR=C:/Program Files (x86)/Intel/oneAPI/tbb/2023.1/lib/cmake/tbb" "-DHDF5_DIR=C:/Program Files/HDF_Group/HDF5/2.1.1/cmake"` | 0 | Approved MSVC x64 build tree regenerates with explicit dependencies | Configure/generate completed; oneMKL 2026.1 dynamic ILP64 backend resolved |
| VERIFY-build | `cmake --build .harness/build --config Debug` | 0 | Full Debug build passes without a new FESA warning | `fesa_solver.lib` and `fesa_unit_tests.exe` built under `/W4 /WX` |
| VERIFY-targeted | `ctest --test-dir .harness/build -C Debug -R DenseMath --output-on-failure` | 0 | Focused dense-math suite remains green | 2/2 tests passed |
| VERIFY-discovery | `ctest --test-dir .harness/build -C Debug --show-only=json-v1` | 0 | CTest discovers the accumulated tests and both exact DenseMath names | 7 tests discovered with feature/unit labels |
| VERIFY-full | `ctest --test-dir .harness/build -C Debug --output-on-failure` | 0 | Full accumulated C++ suite has zero failures | 7/7 tests passed |
| VERIFY-public-header | `$leaks = rg -n "mkl\.h\|MKL_INT\|CBLAS_" include/fesa; if ($LASTEXITCODE -eq 0) { throw "MKL API leaked into public headers:`n$leaks" }; if ($LASTEXITCODE -ne 1) { throw 'Public-header dependency scan failed' }` | 0 | Public headers remain independent of oneMKL API and types | `rg` returned the required no-match exit 1; wrapper scan completed with zero leaks |

- contract_checks: `Vector` accepts zero size, owns contiguous doubles, deep-copies,
  leaves moved-from objects empty and usable, checks every index, and rejects dot/axpy
  mismatches; `Matrix` accepts zero dimensions, owns row-major contiguous doubles,
  deep-copies, leaves moved-from objects empty and usable, checks every index, and
  rejects GEMV/GEMM mismatches. Hand-derived nonsquare GEMV `[50,122]` and GEMM
  `[[58,64],[139,154]]` pass. All copy, dot, norm, scale, axpy, GEMV, and GEMM calls
  cross CBLAS only inside `.cpp` files. Windows tests stage the package-resolved
  oneMKL/OpenMP runtime before post-build discovery because the exact shell does not
  assume oneAPI in `PATH`.
- generated_evidence: `.harness/build/src/fesa/Debug/fesa_solver.lib`,
  `.harness/build/tests/Debug/fesa_unit_tests.exe`
- reference_diff: unchanged; `git diff --exit-code -- reference/` exit 0
- handoff: backend-free `fesa::Vector` and `fesa::Matrix` public APIs, with owning
  dense storage and checked BLAS operations, are available to Step 10 and later
  DOF/element/assembly tasks.