# Analysis State And Analysis Base Implementation Plan

## Metadata
- feature_id: analysis-state-analysis-base
- source_requirement: AGENTS.md; docs/PRD.md
- source_research: N/A for this architecture foundation slice
- source_formulation: N/A for this architecture foundation slice
- source_numerical_review: N/A for this architecture foundation slice
- source_io_definition: docs/ARCHITECTURE.md state ownership and analysis strategy rules
- source_reference_models: N/A for this architecture foundation slice
- status: ready-for-implementation
- owner_agent: implementation-planning-agent
- date: 2026-06-09

## Readiness Check

| input | required_status | observed_status | decision |
| --- | --- | --- | --- |
| architecture | Domain, Analysis, AnalysisState boundaries documented | documented in docs/ARCHITECTURE.md and ADR-010 | proceed |
| domain foundation | Domain runtime storage available | implemented in prior phases | proceed |
| formulation | not required for state/interface foundation | N/A | proceed |
| numerical_review | not required for state/interface foundation | N/A | proceed |
| io_definition | not required; no result output in this phase | N/A | proceed |
| reference_models | not required because this phase produces no solver result | N/A | proceed |

## Implementation Scope

- included_behavior: `AnalysisState` mutable vector state for displacement, external force, internal force, residual, and reaction.
- included_behavior: `AnalysisState` time, increment, and iteration counters.
- included_behavior: `Analysis` base interface for future analysis strategies.
- included_behavior: CMake/CTest registration for analysis-layer unit tests.
- excluded_behavior: `AnalysisModel`, `DofManager`, equation numbering, global assembly, boundary-condition elimination, linear solve, MITC4 numerical formulation, HDF5 output, and reference comparison.
- non_goals: numerical correctness claims, release readiness, reference-solver execution, and reference artifact generation.

## AnalysisState Contract

`AnalysisState` lives under `fesa::core` and owns mutable analysis quantities only. It does not reference or own `Domain`, model objects, equation maps, sparse matrices, solvers, result writers, or reference artifacts.

Required interface:

```cpp
namespace fesa::core {

class AnalysisState {
public:
    AnalysisState();
    explicit AnalysisState(std::size_t dof_count);

    std::size_t dofCount() const noexcept;
    void resize(std::size_t dof_count);

    const std::vector<double>& displacement() const noexcept;
    const std::vector<double>& externalForce() const noexcept;
    const std::vector<double>& internalForce() const noexcept;
    const std::vector<double>& residual() const noexcept;
    const std::vector<double>& reaction() const noexcept;

    void setDisplacement(std::vector<double> values);
    void setExternalForce(std::vector<double> values);
    void setInternalForce(std::vector<double> values);
    void setResidual(std::vector<double> values);
    void setReaction(std::vector<double> values);
    void clearForces() noexcept;

    double currentTime() const noexcept;
    void setCurrentTime(double value) noexcept;
    std::int64_t incrementIndex() const noexcept;
    void setIncrementIndex(std::int64_t value) noexcept;
    std::int64_t iterationIndex() const noexcept;
    void setIterationIndex(std::int64_t value) noexcept;
};

} // namespace fesa::core
```

This phase intentionally defers velocity, acceleration, temperature, element state, and integration-point state until dynamic, thermal, nonlinear, or element-state phases define concrete contracts.

## Analysis Base Contract

`Analysis` lives under `fesa::analysis` and is the base strategy interface for future analysis algorithms. `Domain` is immutable input. `AnalysisState` is mutable output/state.

Required interface:

```cpp
namespace fesa::analysis {

class Analysis {
public:
    virtual ~Analysis() = default;

    virtual const char* name() const noexcept = 0;
    void run(const fesa::core::Domain& domain, fesa::core::AnalysisState& state);

protected:
    virtual void doRun(const fesa::core::Domain& domain, fesa::core::AnalysisState& state) = 0;
};

} // namespace fesa::analysis
```

`Analysis::run` is only an entry-point wrapper in this phase. It does not define assembly, solve, boundary-condition, or output hooks until `AnalysisModel` and `DofManager` exist.

## Work Breakdown

| task_id | order | purpose | upstream_trace | depends_on | expected_test_first |
| --- | --- | --- | --- | --- | --- |
| ASAB-001 | 1 | record state and base-analysis contract | ADR-010; docs/ARCHITECTURE.md | none | N/A |
| ASAB-002 | 2 | add `AnalysisState` zero-sized and sized state | ADR-010 AnalysisState | ASAB-001 | ASAB-TEST-001 |
| ASAB-003 | 3 | add `AnalysisState` mutation guards and counters | docs/ARCHITECTURE.md State Ownership | ASAB-002 | ASAB-TEST-002 |
| ASAB-004 | 4 | add `Analysis` base interface | docs/ARCHITECTURE.md Analysis strategy | ASAB-003 | ASAB-TEST-003 |
| ASAB-005 | 5 | register analysis CTest path | AGENTS.md C++ validation | ASAB-004 | ASAB-TEST-004 |
| ASAB-006 | 6 | record build/test evidence and handoff | docs/build-test-reports/README.md | ASAB-005 | ASAB-TEST-005 |

## TDD Test Plan

| test_id | order | test_type | red_condition | green_condition | linked_task | command |
| --- | --- | --- | --- | --- | --- | --- |
| ASAB-TEST-001 | 1 | unit | `AnalysisState` header/class missing | default and sized state tests pass | ASAB-002 | `ctest --test-dir build/msvc-debug --output-on-failure -C Debug -R analysis` |
| ASAB-TEST-002 | 2 | unit | setter/guard methods missing | mutation guard and counter tests pass | ASAB-003 | `ctest --test-dir build/msvc-debug --output-on-failure -C Debug -R analysis` |
| ASAB-TEST-003 | 3 | unit | `Analysis` header/base missing | derived recording analysis tests pass | ASAB-004 | `ctest --test-dir build/msvc-debug --output-on-failure -C Debug -R analysis` |
| ASAB-TEST-004 | 4 | integration | analysis tests not registered or not built | `ctest -R analysis` runs analysis target | ASAB-005 | `ctest --test-dir build/msvc-debug --output-on-failure -C Debug -R "analysis|domain|model-object|io"` |
| ASAB-TEST-005 | 5 | validation | report evidence missing | validation report records passing commands or classified failure | ASAB-006 | `python scripts/validate_workspace.py` |

## CMake/CTest Plan

- target_candidates: `fesa_core`, `fesa_analysis_tests`
- add_test_needs: register `analysis.base`
- labels: `analysis`, `core`
- msvc_config: Debug
- expected_feature_command: `ctest --test-dir build/msvc-debug --output-on-failure -C Debug -R analysis`
- workspace_validation: `python scripts/validate_workspace.py`

## Candidate Files and Ownership

| file_candidate | purpose | owner_boundary | notes |
| --- | --- | --- | --- |
| `include/fesa/core/AnalysisState.hpp` | mutable analysis state public contract | core state | no Domain/model object ownership |
| `src/core/AnalysisState.cpp` | state vector/counter implementation | core state | no solver logic |
| `include/fesa/analysis/Analysis.hpp` | base analysis strategy interface | analysis | no LinearStaticAnalysis implementation |
| `tests/core/analysis_state_test.cpp` | state TDD coverage | tests | write before production changes |
| `tests/analysis/analysis_base_test.cpp` | analysis base TDD coverage | tests | write before production changes |
| `CMakeLists.txt` | source and CTest registration | build | MSVC Debug compatible |

## Acceptance Traceability Matrix

| requirement_id | task_id | test_id | reference_model_id | acceptance_criterion | status |
| --- | --- | --- | --- | --- | --- |
| ASAB-REQ-001 mutable state is outside Domain | ASAB-002 | ASAB-TEST-001 | N/A | AnalysisState tests pass and Domain remains unchanged | draft |
| ASAB-REQ-002 state vectors are size-consistent | ASAB-003 | ASAB-TEST-002 | N/A | size mismatch throws and failed setters do not mutate | draft |
| ASAB-REQ-003 Analysis takes const Domain and mutable state | ASAB-004 | ASAB-TEST-003 | N/A | recording analysis updates state through base API | draft |
| ASAB-REQ-004 C++ validation path includes analysis tests | ASAB-005 | ASAB-TEST-004 | N/A | `ctest -R analysis` runs successfully | draft |

## Validation Commands

```powershell
ctest --test-dir build/msvc-debug --output-on-failure -C Debug -R analysis
ctest --test-dir build/msvc-debug --output-on-failure -C Debug -R "analysis|domain|model-object|io"
python -m unittest discover -s scripts -p "test_*.py"
python scripts/validate_workspace.py
git diff --check
```

## Risks and Downstream Handoff

### Implementation Agent

- Keep `AnalysisState` as storage only.
- Keep `Analysis` as a base interface only.
- Do not introduce `LinearStaticAnalysis` until `AnalysisModel` and `DofManager` contracts exist.

### Build/Test Executor Agent

- Use Visual Studio 17 2022, x64, Debug, and `build/msvc-debug`.
- Use `python scripts/validate_workspace.py` as canonical validation.

### Correction Agent

- Implementation-owned failures are expected to be compile or unit-test failures in state headers, state sources, analysis header, analysis tests, or CMake registration.
- Upstream-contract failures include requests to add equation numbering, assembly, solver behavior, HDF5 output, or numerical MITC4 behavior in this phase.

### Reference Verification Agent

- No reference verification is required for this phase.
- This phase produces no HDF5 result and consumes no reference artifacts.

## Open Issues

- `AnalysisModel`, `DofManager`, and `LinearStaticAnalysis` remain separate downstream phases.