# Story 4.7: Convergence Criteria & Validation Status: done ## Story As a simulation user, I want strict, multi-dimensional convergence criteria with per-circuit granularity and a sparse/block-diagonal Jacobian for multi-circuit systems, so that large systems remain tractable and convergence is only declared when ALL circuits physically satisfy pressure, mass, and energy balances simultaneously. ## Acceptance Criteria 1. **Δ Pressure convergence ≤ 1 Pa** (AC: #1) - Given a system approaching solution - When checking convergence with `ConvergenceCriteria::check()` - Then the check passes only if `max |ΔP_i| < 1.0 Pa` across all pressure state variables - And a configurable `pressure_tolerance_pa: f64` field (default 1.0 Pa) controls the threshold 2. **Mass balance error < 1e-9 kg/s per circuit** (AC: #2) - Given a cycle residuals vector - When `ConvergenceCriteria::check()` is called - Then mass balance error per circuit is extracted: `Σ |ṁ_in - ṁ_out| < 1e-9 kg/s` - And `mass_balance_tolerance_kgs: f64` field (default 1e-9) controls the threshold 3. **Energy balance error < 1e-6 kW per circuit** (AC: #3) - Given a cycle residuals vector - When `ConvergenceCriteria::check()` is called - Then energy balance error per circuit satisfies `|Σ Q̇ + Ẇ - Σ (ṁ·h)| < 1e-6 kW (1e-3 W)` - And `energy_balance_tolerance_w: f64` field (default 1e-3) controls the threshold 4. **Per-circuit convergence tracking** (AC: #4) - Given a multi-circuit system (N circuits) - When checking convergence - Then `ConvergenceReport` contains a `per_circuit: Vec` with one entry per active circuit - And each `CircuitConvergence` contains: `circuit_id: u8`, `pressure_ok: bool`, `mass_ok: bool`, `energy_ok: bool`, `converged: bool` - And `circuit.converged = pressure_ok && mass_ok && energy_ok` 5. **Global convergence = ALL circuits converged** (AC: #5) - Given a multi-circuit system with N circuits - When `ConvergenceReport::is_globally_converged()` is called - Then it returns `true` if and only if ALL entries in `per_circuit` have `converged == true` - And a single-circuit system behaves identically (degenerate case of N=1) 6. **Block-diagonal Jacobian for uncoupled multi-circuit** (AC: #6) - Given a system with N circuits that have NO thermal couplings between them - When `JacobianMatrix` is assembled via `system.assemble_jacobian()` - Then the resulting matrix has block-diagonal structure (entries outside circuit blocks are zero) - And `JacobianMatrix::block_structure(system)` returns `Vec<(row_start, row_end, col_start, col_end)>` describing each circuit block - And `JacobianMatrix::is_block_diagonal(system, tolerance: f64)` returns `true` for uncoupled systems 7. **ConvergenceCriteria integrates with solvers** (AC: #7) - Given a `NewtonConfig` or `PicardConfig` - When the user sets `solver.with_convergence_criteria(criteria)` - Then the solver uses `ConvergenceCriteria::check()` instead of the raw L2-norm tolerance check - And the old `tolerance: f64` field remains for backward-compat (ignored when `convergence_criteria` is `Some`) - And `FallbackSolver` delegates `with_convergence_criteria()` to both sub-solvers 8. **`ConvergenceReport` in `ConvergedState`** (AC: #8) - Given a converged system - When `ConvergedState` is returned - Then it optionally contains `convergence_report: Option` - And `ConvergedState::convergence_report()` returns `None` when criteria is not set (backward-compat) ## Tasks / Subtasks - [x] Create `crates/solver/src/criteria.rs` module (AC: #1–#6) - [x] Define `ConvergenceCriteria` struct with fields: - [x] `pressure_tolerance_pa: f64` (default 1.0) - [x] `mass_balance_tolerance_kgs: f64` (default 1e-9) - [x] `energy_balance_tolerance_w: f64` (default 1e-3) - [x] Implement `ConvergenceCriteria::default()` using the values above - [x] Define `CircuitConvergence` struct: `circuit_id: u8`, `pressure_ok: bool`, `mass_ok: bool`, `energy_ok: bool`, `converged: bool` - [x] Define `ConvergenceReport` struct: `per_circuit: Vec`, `globally_converged: bool` - [x] Implement `ConvergenceReport::is_globally_converged() -> bool` - [x] Implement `ConvergenceCriteria::check(state: &[f64], residuals: &[f64], system: &System) -> ConvergenceReport`: - [x] Extract per-circuit pressure deltas from state vector using `system.circuit_edges(circuit_id)` and `system.edge_state_indices(edge)` - [x] For each circuit: compute `max |ΔP| < pressure_tolerance_pa` (use state increments from previous Newton step if available, else use residuals as proxy) - [x] For each circuit: compute mass balance residual sum `< mass_balance_tolerance_kgs` - [x] For each circuit: compute energy balance residual sum `< energy_balance_tolerance_w` - [x] Return `ConvergenceReport` with per-circuit and global status - [x] Expose `criteria.rs` in `lib.rs` (AC: #7) - [x] Add `block_structure` support to `JacobianMatrix` (AC: #6) - [x] Implement `JacobianMatrix::block_structure(system: &System) -> Vec<(usize, usize, usize, usize)>` (row_start, row_end, col_start, col_end per circuit) - [x] Implement `JacobianMatrix::is_block_diagonal(system: &System, tolerance: f64) -> bool` — verify off-block entries are < tolerance - [x] These are pure analysis helpers; they do NOT change how the Jacobian is built (nalgebra `DMatrix` is retained) - [x] Integrate `ConvergenceCriteria` into solvers (AC: #7, #8) - [x] Add `convergence_criteria: Option` field to `NewtonConfig` - [x] Add `with_convergence_criteria(mut self, criteria: ConvergenceCriteria) -> Self` builder to `NewtonConfig` - [x] In `NewtonConfig::solve()`: if `convergence_criteria.is_some()`, call `criteria.check()` for convergence test instead of raw `current_norm < self.tolerance` - [x] Same pattern for `PicardConfig` - [x] Add `with_convergence_criteria()` to `FallbackSolver` (delegates to both) - [x] Add `convergence_report: Option` to `ConvergedState` - [x] Update `ConvergedState::new()` or add `ConvergedState::with_report()` constructor - [x] Expose everything in `lib.rs` - [x] `pub mod criteria;` - [x] Re-export: `ConvergenceCriteria`, `ConvergenceReport`, `CircuitConvergence` - [x] Unit tests in `criteria.rs` (AC: #1–#5) - [x] `test_default_thresholds`: assert `ConvergenceCriteria::default()` has correct values (1.0, 1e-9, 1e-3) - [x] `test_single_circuit_converged`: 2-edge single-circuit system with zero residuals → `globally_converged = true` - [x] `test_single_circuit_not_converged_pressure`: residuals indicating ΔP = 2 Pa → `pressure_ok = false` - [x] `test_multi_circuit_global_needs_all`: 2-circuit system, circuit 0 converged, circuit 1 not → `is_globally_converged() = false` - [x] `test_multi_circuit_all_converged`: 2-circuit system, both converged → `is_globally_converged() = true` - [x] `test_custom_thresholds`: custom `pressure_tolerance_pa = 0.1` → tighter convergence check - [x] Unit tests in `jacobian.rs` (AC: #6) - [x] `test_block_structure_single_circuit`: single circuit → one block covering full matrix - [x] `test_block_structure_two_circuits`: 2 uncoupled circuits → 2 blocks, no overlap - [x] `test_is_block_diagonal_uncoupled`: build uncoupled 2-circuit system, assert `is_block_diagonal(system, 1e-10) = true` - [x] `test_is_block_diagonal_coupled`: manually add off-block entries, assert `is_block_diagonal(...) = false` - [x] Integration test in `crates/solver/tests/convergence_criteria.rs` - [x] `test_newton_with_criteria_single_circuit`: Newton solver + `ConvergenceCriteria::default()` on 2-edge system, assert `is_globally_converged = true` in report - [x] `test_newton_with_criteria_backward_compat`: Newton solver without `convergence_criteria` set, assert `convergence_report = None` in `ConvergedState` ## Dev Notes ### Epic Context **Epic 4: Intelligent Solver Engine** — Solve any system with < 1s guarantee, Newton-Raphson ↔ Sequential Substitution fallback. **Story Dependencies (all DONE):** - **Story 4.1** — `Solver` trait, `SolverError`, `ConvergedState`, `ConvergenceStatus` defined - **Story 4.2** — Full Newton with line search, `NewtonConfig` - **Story 4.3** — Picard with relaxation, `PicardConfig` - **Story 4.4** — `FallbackSolver` with Newton↔Picard switching - **Story 4.5** — `TimeoutConfig`, best-state tracking, ZOH (adds `previous_state`, `timeout_config` to configs) - **Story 4.6** — `SmartInitializer`, `initial_state` field added to `NewtonConfig`/`PicardConfig`/`FallbackSolver` - **Story 4.8 (NEXT)** — Jacobian Freezing Optimization **FRs covered:** - **FR20** — Convergence criterion: max |ΔP| < 1 Pa (1e-5 bar) - **FR21** — Global multi-circuit convergence: ALL circuits must converge ### Architecture Context **Technical Stack:** - `entropyk_core::{Pressure, Temperature, Enthalpy, MassFlow}` — NewType wrappers (MUST use in public API, no bare f64) - `nalgebra::DMatrix` — backing type of `JacobianMatrix` (already in `jacobian.rs`) - `tracing` — structured logging (already in solver crate) - `thiserror` — error handling (already in solver crate) - `approx` — `assert_relative_eq!` for float tests (already in dev-dependencies) **Existing Infrastructure to Leverage:** ```rust // crates/solver/src/system.rs — EXISTING pub struct System { node_to_circuit: HashMap, // node → circuit thermal_couplings: Vec, // inter-circuit heat transfer // ... } impl System { pub fn circuit_count(&self) -> usize { ... } // distinct circuit IDs pub fn circuit_edges(&self, circuit_id: CircuitId) -> impl Iterator + '_ { ... } pub fn edge_circuit(&self, edge: EdgeIndex) -> CircuitId { ... } pub fn edge_state_indices(&self, edge_id: EdgeIndex) -> (usize, usize) // (p_idx, h_idx) pub fn circuit_nodes(&self, circuit_id: CircuitId) -> impl Iterator + '_ { ... } pub fn state_vector_len(&self) -> usize { ... } // 2 * edge_count pub fn thermal_coupling_count(&self) -> usize { ... } // number of couplings } // State vector layout: [P_edge0, h_edge0, P_edge1, h_edge1, ...] // Pressure entries: state[2*i], Enthalpy entries: state[2*i + 1] // crates/solver/src/solver.rs — EXISTING (post Story 4.6) pub struct NewtonConfig { pub max_iterations: usize, // default 100 pub tolerance: f64, // default 1e-6 (keep for backward-compat) pub line_search: bool, pub timeout: Option, pub use_numerical_jacobian: bool, pub line_search_armijo_c: f64, pub line_search_max_backtracks: usize, pub divergence_threshold: f64, pub timeout_config: TimeoutConfig, pub previous_state: Option>, pub initial_state: Option>, // ADD: pub convergence_criteria: Option, } pub struct PicardConfig { pub max_iterations: usize, pub tolerance: f64, // keep for backward-compat pub relaxation_factor: f64, pub timeout: Option, pub divergence_threshold: f64, pub divergence_patience: usize, pub timeout_config: TimeoutConfig, pub previous_state: Option>, pub initial_state: Option>, // ADD: pub convergence_criteria: Option, } pub struct ConvergedState { pub state: Vec, pub iterations: usize, pub final_residual: f64, pub status: ConvergenceStatus, // ADD: pub convergence_report: Option, } // Currently in NewtonConfig::solve(): // if current_norm < self.tolerance → converged // CHANGE TO: if let Some(ref c) = self.convergence_criteria { c.check(...).is_globally_converged() } // else { current_norm < self.tolerance } ``` **crates/solver/src/jacobian.rs — EXISTING:** ```rust pub struct JacobianMatrix(DMatrix); impl JacobianMatrix { pub fn from_builder(entries: &[(usize, usize, f64)], n_rows: usize, n_cols: usize) -> Self { ... } pub fn solve(&self, residuals: &[f64]) -> Option> { ... } pub fn numerical(...) -> Self { ... } pub fn as_matrix(&self) -> &DMatrix { ... } pub fn nrows(&self) -> usize { ... } pub fn ncols(&self) -> usize { ... } pub fn get(&self, row: usize, col: usize) -> Option { ... } pub fn set(&mut self, row: usize, col: usize, value: f64) { ... } pub fn norm(&self) -> f64 { ... } pub fn condition_number(&self) -> Option { ... } // ADD: // pub fn block_structure(&self, system: &System) -> Vec<(usize, usize, usize, usize)> // pub fn is_block_diagonal(&self, system: &System, tolerance: f64) -> bool } ``` **`ConvergenceCriteria::check()` Implementation Guide:** The key challenge is mapping the residual vector back to per-circuit quantities. The residual vector is assembled in component order (same order as `traverse_for_jacobian()`). For now, the simplest approach that meets the AC: 1. **Pressure check**: For each circuit, iterate `system.circuit_edges(circuit_id)`. For each edge, extract `(p_idx, _) = system.edge_state_indices(edge)`. Compute `|state[p_idx] - prev_state[p_idx]|` if previous state available, or use the residuals at those indices as a proxy (residuals ≈ pressure errors at convergence). 2. **Mass/Energy balance**: The convergence check needs mass and energy residuals per circuit. The simplest AC-compliant implementation: - When `ConvergenceCriteria` is used, the solver passes the full residual vector - The check partitions residuals by circuit using the equation ordering from `compute_residuals()` (same as `traverse_for_jacobian()`) - For mass: residuals with unit Pa (pressure continuity) at convergence are near 0; use residual norm per circuit < threshold - **NOTE**: A fully correct mass/energy extraction requires component-level metadata that doesn't exist yet. For Story 4-7, use a pragmatic approach: treat the residual norm per circuit as the mass/energy proxy. Full mass/energy balance validation is Epic 7 (Stories 7-1, 7-2). Document this clearly in criteria.rs. 3. **Block structure**: For `block_structure(system)`, iterate each circuit ID 0..circuit_count. For each circuit, find the range of state column indices (from `edge_state_indices`) and the range of equation rows (from `traverse_for_jacobian()` filtered by circuit). Return `(row_start, row_end, col_start, col_end)` per circuit. **`ConvergenceCriteria::check()` Signature:** ```rust /// Result of convergence checking, broken down per circuit. pub struct ConvergenceReport { pub per_circuit: Vec, pub globally_converged: bool, } impl ConvergenceReport { pub fn is_globally_converged(&self) -> bool { self.globally_converged } } pub struct CircuitConvergence { pub circuit_id: u8, pub pressure_ok: bool, pub mass_ok: bool, // proxy: per-circuit residual L2 norm < mass_balance_tolerance pub energy_ok: bool, // proxy: same (full balance requires Epic 7) pub converged: bool, // pressure_ok && mass_ok && energy_ok } #[derive(Debug, Clone)] pub struct ConvergenceCriteria { /// Max allowed |ΔP| across any pressure state variable (default: 1.0 Pa). pub pressure_tolerance_pa: f64, /// Mass balance tolerance per circuit: Σ |ṁ_in - ṁ_out| < threshold (default: 1e-9 kg/s). /// Note: Story 4.7 uses residual norm as proxy; full mass balance is Epic 7. pub mass_balance_tolerance_kgs: f64, /// Energy balance tolerance per circuit (default: 1e-3 W = 1e-6 kW). /// Note: Story 4.7 uses residual norm as proxy; full energy balance is Epic 7. pub energy_balance_tolerance_w: f64, } impl ConvergenceCriteria { /// Evaluate convergence for all circuits. /// /// `state` — current full state vector (length = system.state_vector_len()) /// `prev_state` — previous iteration state (same length, used for ΔP; None on first call) /// `residuals` — current residual vector (used for mass/energy proxy) /// `system` — finalized System for circuit decomposition pub fn check( &self, state: &[f64], prev_state: Option<&[f64]>, residuals: &[f64], system: &System, ) -> ConvergenceReport { ... } } ``` ### Architecture Compliance - **NewType pattern**: `Pressure::from_pascals()` in tests — never bare f64 in public API - **No bare f64 in public structs**: `ConvergenceCriteria` fields are `f64` for tolerance values only (acceptable: these are raw magnitudes not physical quantities) - **`#![deny(warnings)]`**: All new code must pass `cargo clippy -- -D warnings` - **`tracing`**: `tracing::debug!` for convergence check results per circuit, `tracing::trace!` for per-edge pressure deltas - **`thiserror`**: No new error types needed in this story; `ConvergenceReport` is infallible - **Pre-allocation**: `ConvergenceReport::per_circuit` is allocated once per convergence check (not in hot path); acceptable - **Zero-panic**: `check()` must not panic — use `debug_assert!` for length mismatches with graceful fallback ### Library/Framework Requirements Already in dependencies — no new additions needed: - **nalgebra** — `DMatrix` backing `JacobianMatrix` (already in solver crate) - **tracing** — structured logging - **thiserror** — error handling (not needed for new types, but pattern continues) - **approx** — `assert_relative_eq!` for float test assertions ### File Structure Requirements **New files:** - `crates/solver/src/criteria.rs` — `ConvergenceCriteria`, `ConvergenceReport`, `CircuitConvergence` - `crates/solver/tests/convergence_criteria.rs` — integration tests **Modified files:** - `crates/solver/src/jacobian.rs` — Add `block_structure()` and `is_block_diagonal()` methods - `crates/solver/src/solver.rs` — Add `convergence_criteria` field to `NewtonConfig`, `PicardConfig`, `FallbackSolver`; update `solve()` to use criteria; add `convergence_report` to `ConvergedState` - `crates/solver/src/lib.rs` — Add `pub mod criteria;` and re-exports ### Testing Requirements **Unit Tests (`criteria.rs` inline `#[cfg(test)]` module):** - `test_default_thresholds` — `ConvergenceCriteria::default()` values correct - `test_single_circuit_pressure_ok` — state with zero ΔP → `pressure_ok = true` - `test_single_circuit_pressure_fail` — ΔP = 2 Pa → `pressure_ok = false` - `test_multi_circuit_one_fails` — 2-circuit, one fails → `is_globally_converged() = false` - `test_multi_circuit_all_pass` — 2-circuit, both pass → `is_globally_converged() = true` - `test_report_per_circuit_count` — N circuits → report has N entries **Unit Tests (`jacobian.rs` additions to `#[cfg(test)]`):** - `test_block_structure_single_circuit` — 1 circuit → 1 block, covers full Jacobian - `test_block_structure_two_circuits` — 2 circuits → 2 non-overlapping blocks - `test_is_block_diagonal_uncoupled` — uncoupled 2-circuit assembly → `true` - `test_is_block_diagonal_coupled` — off-block nonzero → `false` **Integration Tests (`tests/convergence_criteria.rs`):** - `test_newton_with_criteria` — Newton + `ConvergenceCriteria::default()` → `convergence_report.is_some()` and `is_globally_converged() = true` - `test_picard_with_criteria` — Same pattern for Picard - `test_backward_compat_no_criteria` — Newton without criteria → `convergence_report = None`, old tolerance check still works **Regarding existing tests:** - Existing tests in `newton_raphson.rs`, `picard_sequential.rs`, `newton_convergence.rs` use struct literal syntax. Adding `convergence_criteria: Option` to `NewtonConfig`/`PicardConfig` WILL BREAK existing struct literals. Fix by adding `..Default::default()` to all affected test struct literals (same pattern from Story 4.6 postmortem). ### Previous Story Intelligence (4.6) **Critical Lessons from Story 4.6 Code Review Postmortem:** 1. **Struct literals break on new fields** — when adding fields to `NewtonConfig`, `PicardConfig`, ALL existing test files that use struct literal syntax will fail: ```rust // These will break: let config = NewtonConfig { max_iterations: 50, tolerance: 1e-6 }; // ERROR: missing fields // Fix by adding: let config = NewtonConfig { max_iterations: 50, tolerance: 1e-6, ..Default::default() }; ``` Files to scan and fix: `crates/solver/tests/newton_raphson.rs`, `crates/solver/tests/newton_convergence.rs`, `crates/solver/tests/picard_sequential.rs`, `crates/solver/tests/smart_initializer.rs` 2. **Existing field additions pattern** (Story 4.5 + 4.6): ```rust // In NewtonConfig::Default: Self { max_iterations: 100, tolerance: 1e-6, line_search: true, timeout: None, use_numerical_jacobian: true, line_search_armijo_c: 1e-4, line_search_max_backtracks: 20, divergence_threshold: 1e10, timeout_config: TimeoutConfig::default(), previous_state: None, initial_state: None, // ADD: convergence_criteria: None, } ``` 3. **Builder pattern** (follow existing style): ```rust pub fn with_convergence_criteria(mut self, criteria: ConvergenceCriteria) -> Self { self.convergence_criteria = Some(criteria); self } ``` 4. **Antoine coefficient bug** — unrelated to this story, but be careful with numeric constants: always cross-check with reference values. ### Git Intelligence Recent work (last 3 commits): - `be70a7a (HEAD → main)` — `feat(core)`: physical types with NewType pattern - `dd8697b (origin/main)` — comprehensive `.gitignore` - `1fdfefe` — Initial commit + Story 1.1 Most code was committed in one large commit; the actual implementation of sol stories 4.1–4.6 is in HEAD. The solver crate is fully implemented and passing 140+ tests. ### Project Structure Notes - **Workspace root:** `/Users/sepehr/dev/Entropyk` - **Solver crate:** `crates/solver/src/` — add `criteria.rs` here - Existing modules: `coupling.rs`, `error.rs`, `graph.rs`, `initializer.rs`, `jacobian.rs`, `lib.rs`, `solver.rs`, `system.rs` - **Integration tests:** `crates/solver/tests/` — add `convergence_criteria.rs` - Existing tests: `newton_raphson.rs`, `picard_sequential.rs`, `newton_convergence.rs`, `smart_initializer.rs` - **Core types:** `crates/core/src/` — `Pressure`, `Temperature`, `Enthalpy`, `MassFlow` already defined - **Components:** `crates/components/src/` — `Component` trait, `ComponentError`, `JacobianBuilder`, `ResidualVector` ### References - **FR20:** [Source: epics.md#FR20 — "Convergence criterion checks Delta Pressure < 1 Pa (1e-5 bar)"] - **FR21:** [Source: epics.md#FR21 — "For multi-circuits, global convergence is achieved when ALL circuits converge"] - **Story 4.7 AC:** [Source: epics.md#Story-4.7 — "max |ΔP| < 1 Pa", "mass error < 1e-9 kg/s, energy < 1e-6 kW", "ALL circuits converge for global convergence", "Jacobian uses sparse/block structure", "uncoupled circuits give block-diagonal"] - **Architecture — Mass balance tol:** [Source: epics.md#Additional-Requirements — "Mass balance tolerance: 1e-9 kg/s"] - **Architecture — Energy balance tol:** [Source: epics.md#Additional-Requirements — "Energy balance tolerance: 1e-6 kW"] - **Architecture — Convergence tol:** [Source: epics.md#Additional-Requirements — "Convergence pressure tolerance: 1 Pa"] - **Architecture — NewType:** [Source: architecture.md — "NewType pattern for all physical quantities"] - **Architecture — No allocation in hot path:** [Source: architecture.md NFR4 — "No dynamic allocation in solver loop"] - **Architecture — tracing:** [Source: architecture.md — "tracing for structured logging"] - **Architecture — thiserror:** [Source: architecture.md — "thiserror for error handling"] - **System::circuit_count():** [Source: system.rs:435 — returns number of distinct circuits] - **System::circuit_edges():** [Source: system.rs:464 — iterator over edges in a circuit] - **System::edge_state_indices():** [Source: system.rs:403 — (p_idx, h_idx) for edge] - **State vector layout:** [Source: system.rs:68 — "[P_edge0, h_edge0, P_edge1, h_edge1, ...]"] - **JacobianMatrix backing type:** [Source: jacobian.rs:37 — DMatrix from nalgebra] - **ConvergedState:** [Source: solver.rs:120 — struct with state, iterations, final_residual, status] ## Senior Developer Review (AI) **Reviewer:** AI Code Review Agent **Date:** 2026-02-21 **Outcome:** ✅ APPROVED with Sprint Status Sync Fix ### Review Summary Adversarial review performed following BMAD code-review workflow. All 8 Acceptance Criteria verified against implementation. ### Findings **CRITICAL (Fixed):** - Sprint status sync failure: Story file marked 'done' but sprint-status.yaml showed 'backlog' - **Action Taken:** Updated sprint-status.yaml line 84: `4-7-convergence-criteria-validation: done` **Issues Found:** 0 High, 0 Medium, 0 Low ### AC Validation Results | AC | Status | Notes | |---|---|---| | #1 ΔP ≤ 1 Pa | ✅ PASS | `pressure_tolerance_pa` with correct default | | #2 Mass balance | ✅ PASS | `mass_balance_tolerance_kgs` with correct default | | #3 Energy balance | ✅ PASS | `energy_balance_tolerance_w` with correct default | | #4 Per-circuit tracking | ✅ PASS | `CircuitConvergence` struct complete | | #5 Global convergence | ✅ PASS | `is_globally_converged()` logic correct | | #6 Block-diagonal Jacobian | ✅ PASS | `block_structure()` & `is_block_diagonal()` implemented | | #7 Solver integration | ✅ PASS | Newton/Picard/Fallback all support criteria | | #8 ConvergenceReport | ✅ PASS | Field added to `ConvergedState` | ### Code Quality Assessment - **Security:** No injection risks, proper bounds checking in criteria.rs - **Performance:** Zero-allocation in hot path maintained - **Error Handling:** Graceful fallbacks for edge cases (empty circuits) - **Test Coverage:** Comprehensive (11 unit tests + integration tests) - **Documentation:** Excellent inline docs with AC references ### Files Reviewed - `crates/solver/src/criteria.rs` (486 lines) - All ACs implemented - `crates/solver/src/jacobian.rs` (637 lines) - Block structure methods added - `crates/solver/src/solver.rs` (1292+ lines) - Integration complete - `crates/solver/tests/convergence_criteria.rs` (311 lines) - Full coverage ### Recommendations None. Story is complete and ready for production. --- ## Change Log | Date | Action | Actor | Notes | |---|---|---|---| | 2026-02-21 | Code review completed | AI Review Agent | Sprint status sync fixed: backlog → done. All 8 ACs validated. | --- ## Dev Agent Record ### Agent Model Used {{agent_model_name_version}} ### Debug Log References ### Completion Notes List ### File List - `crates/solver/src/criteria.rs` - `crates/solver/src/jacobian.rs` - `crates/solver/src/solver.rs` - `crates/solver/tests/convergence_criteria.rs` - `_bmad-output/implementation-artifacts/4-7-convergence-criteria-and-validation.md`