chore(release): v1.4.1 (#101)

* chore(release): v1.4.1

Patch bump for the per-patch heap-traffic refactor (#100).
pypatchworkpp.patchworkpp gains 14.8% Hz (97.5 -> 111.9 Hz on KITTI
seq 00, i7-12700), driven by killing short-lived vector<PointXYZ> /
Eigen::Matrix allocations in R-VPF + R-GPF. Closes part of #96.

Numerical equivalence verified end-to-end on KITTI seq 00 (4541
frames): F1 delta 0.00 for patchwork classic (bit-identical), +0.01
for patchwork++ (within the ±0.05 macro budget).

Bumps:
- python/pyproject.toml  1.4.0 -> 1.4.1
- cpp/CMakeLists.txt     1.4.0 -> 1.4.1

CHANGELOG.md updated with the full v1.4.1 entry.

See #100.

* chore(release): mdformat CHANGELOG.md

* chore(release): mdformat 0.7.9 escapes

Author: LimHyungTae

CHANGELOG.md

@@ -1,5 +1,70 @@
 # Changelog
 
+## v1.4.1
+
+### Perf — `pypatchworkpp.patchworkpp` per-patch heap traffic eliminated
+
+Three changes inside `PatchWorkpp::extract_piecewiseground` and
+`PatchWorkpp::estimate_plane` take KITTI seq 00 from 10.26 ms to
+8.94 ms per frame (**97.5 Hz → 111.9 Hz, +14.8% Hz**, median of 3
+runs, i7-12700). This closes the part of #96 that was driven by
+short-lived allocations in R-VPF + R-GPF.
+
+**High-impact (this is where the +14.8% comes from):**
+
+- `estimate_plane`: drop the `Eigen::MatrixX3f eigen_ground`,
+  `centered`, and `centered.adjoint() * centered` heap allocations.
+  Replace with a single-pass scalar accumulation of mean and 9
+  cross-products, then build the 3x3 covariance on the stack.
+- `extract_piecewiseground`: promote `src_wo_verticals` and
+  `src_tmp` to reused instance scratch members. `vector::clear()`
+  keeps capacity, so per-patch malloc pressure on the glibc heap
+  (which was serialising the loop, see #96) drops away after the
+  first few patches.
+- `estimateGround` main loop: `auto& zone` instead of `auto zone`
+  for `ConcentricZoneModel_[zone_idx]`. Avoids a deep-copy of the
+  full 3-level nested vector per outer iteration. Safe because each
+  `(zone, ring, sector)` patch is read once and the CZM is flushed
+  at the top of every `estimateGround` call.
+
+**Lower-impact, kept for cleanliness:**
+
+- `JacobiSVD<Matrix3f>` to `SelfAdjointEigenSolver::computeDirect`
+  for the 3x3 PSD covariance in both `cpp/common/src/plane_fit.cpp`
+  and the in-place `PatchWorkpp::estimate_plane`. Closed-form, no
+  Jacobi iterations. `singular_values_` is repacked descending so
+  every consumer (`linearity_` / `planarity_` in `common`,
+  `flatness_thr` index `(2)` in patchwork classic,
+  `ground_flatness=minCoeff()` and `line_variable=sv(0)/sv(1)` in
+  patchwork++) keeps the same convention bit-for-bit.
+- `const&` on `addCloud`'s `add` parameter, `RevertCandidate` loop
+  vars, and the `temporal_ground_revert` /
+  `calc_point_to_plane_d` / `calc_mean_stdev` signatures.
+
+Patchwork classic is unaffected on the perf side: TBB
+`parallel_for` already amortises allocations across cores and SVD
+is sub-us/patch.
+
+### Numerical equivalence
+
+KITTI seq 00 (4541 frames), v1.4.0 to v1.4.1:
+
+| Method (protocol)  | Before                     | After                      |  Δ F1 |
+| ------------------ | -------------------------- | -------------------------- | ----: |
+| `patchwork` (pw)   | P 92.34, R 94.64, F1 93.41 | P 92.34, R 94.64, F1 93.41 |  0.00 |
+| `patchworkpp` (pp) | P 94.88, R 98.47, F1 96.62 | P 94.89, R 98.48, F1 96.63 | +0.01 |
+
+Algebraic identity of `JacobiSVD` vs `eigh` verified on 500 real
+KITTI patch covariances: `normal_` (up to sign),
+`singular_values_`, `linearity_`, `planarity_`, `ground_flatness`,
+`line_variable` all match to FP precision. Both within the ±0.05
+macro budget.
+
+### References
+
+- #100 — PR (perf: alloc-free + eigh)
+- #96 — Issue (R-VPF / R-GPF allocation profile)
+
 ## v1.4.0
 
 ### Refactor — shared `common` library + optional TBB parallelisation
@@ -29,10 +94,10 @@ order so numerical results are byte-identical to the sequential path.
 
 Measured on KITTI seq 00 (i7-12700, 24 logical cores):
 
-| Configuration | Median ms/frame | Median Hz |
-| -- | --: | --: |
-| `--method patchwork` single-thread (taskset -c 0) | 8.31 | 120.4 |
-| `--method patchwork` parallel (TBB default scheduler) | **4.81** | **207.8** |
+| Configuration                                         | Median ms/frame | Median Hz |
+| ----------------------------------------------------- | --------------: | --------: |
+| `--method patchwork` single-thread (taskset -c 0)     |            8.31 |     120.4 |
+| `--method patchwork` parallel (TBB default scheduler) |        **4.81** | **207.8** |
 
 **1.73× speedup**. TBB is an **optional** build dependency: missing
 TBB causes a CMake STATUS message and falls back to a sequential
@@ -63,10 +128,10 @@ or a real user CPU complaint).
 KITTI 00-10 full sweep (23,201 frames), Patchwork++ paper protocol,
 v1.3.1 → v1.4.0:
 
-| Method | F1 v1.3.1 | F1 v1.4.0 | Δ |
-| --- | --- | --- | --- |
-| `--method patchwork` | 96.0172 | 96.0172 | 0 (byte-identical) |
-| `--method patchworkpp` | 96.2918 | 96.2919 | +0.0001 (float noise) |
+| Method                 | F1 v1.3.1 | F1 v1.4.0 | Δ                     |
+| ---------------------- | --------- | --------- | --------------------- |
+| `--method patchwork`   | 96.0172   | 96.0172   | 0 (byte-identical)    |
+| `--method patchworkpp` | 96.2918   | 96.2919   | +0.0001 (float noise) |
 
 Both well within the ±0.05 budget set in the refactor plan.
 
@@ -111,12 +176,12 @@ parameters (`uprightness_thr=0.707`, `using_global_thr=false`) on SemanticKITTI
 sequences 00–10 (23,201 frames), under the Patchwork++ paper evaluation
 protocol (Sec. IV.A — VEGETATION excluded):
 
-| Configuration | Precision | Recall | F1 |
-| --- | --- | --- | --- |
-| v1.2.0 (`pypatchworkpp.patchwork`) | 89.70 | 98.49 | 93.73 |
-| **v1.3.0 (`pypatchworkpp.patchwork`)** | **94.64** | **97.58** | **96.02** |
-| Original Patchwork ROS 2 (reference) | 94.38 | 97.90 | 96.05 |
-| Patchwork++ paper Table I, Patchwork \[1\] | 94.23 | 97.62 | 95.88 |
+| Configuration                            | Precision | Recall    | F1        |
+| ---------------------------------------- | --------- | --------- | --------- |
+| v1.2.0 (`pypatchworkpp.patchwork`)       | 89.70     | 98.49     | 93.73     |
+| **v1.3.0 (`pypatchworkpp.patchwork`)**   | **94.64** | **97.58** | **96.02** |
+| Original Patchwork ROS 2 (reference)     | 94.38     | 97.90     | 96.05     |
+| Patchwork++ paper Table I, Patchwork \[1\] | 94.23     | 97.62     | 95.88     |
 
 **+2.29 F1** vs v1.2.0; within ±0.14 F1 of the original Patchwork ROS 2 build
 and within paper run-to-run variance of Table I.

cpp/CMakeLists.txt

@@ -1,5 +1,5 @@
 cmake_minimum_required(VERSION 3.11)
-project(patchworkpp VERSION 1.4.0)
+project(patchworkpp VERSION 1.4.1)
 
 option(USE_SYSTEM_EIGEN3 "Use system pre-installed Eigen" OFF)
 option(INCLUDE_CPP_EXAMPLES "Include C++ example codes, which require Open3D for visualization" OFF)

python/pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "scikit_build_core.build"
 
 [project]
 name = "pypatchworkpp"
-version = "1.4.0"
+version = "1.4.1"
 requires-python = ">=3.8"
 description = "ground segmentation"
 dependencies = [