From ea236d69700d69a7f81cee8d9917d3883d73aeb6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Eirik=20Kol=C3=A5s?= <kolaseirik@gmail.com>
Date: Fri, 1 Mar 2024 14:35:42 +0100
Subject: [PATCH] 3 bug vortexplottinggauss to ellipse is not exported
 correctly (#6)

* changed cmakelists and ellipse class

* package is successfully imported by other packages

* Committing clang-format changes

* fixed scaling factor in ellipse from gauss constructor

* Committing clang-format changes

* updated clang formatter workflow file

---------

Co-authored-by: Clang Robot <robot@example.com>
---
 .github/workflows/clang-formatter.yml            | 12 ++++++------
 .../include/vortex_filtering/utils/ellipse.hpp   | 16 ++++++++--------
 vortex-filtering/src/utils/ellipse.cpp           | 10 ++++++++--
 3 files changed, 22 insertions(+), 16 deletions(-)

diff --git a/.github/workflows/clang-formatter.yml b/.github/workflows/clang-formatter.yml
index 612029f3..f8643aa6 100644
--- a/.github/workflows/clang-formatter.yml
+++ b/.github/workflows/clang-formatter.yml
@@ -1,19 +1,19 @@
 name: Run clang-format Linter
 
 on: 
-  # push:
-    # branches: [ main ]
+  push:
+    branches: [ main ]
   workflow_dispatch:
 
-  pull_request:
-    types: [opened, reopened]
-    branches: [ main ]
+  # pull_request:
+  #   types: [opened, reopened]
+  #   branches: [ main ]
 jobs:
   build:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - uses: DoozyX/clang-format-lint-action@v0.17
       with:
         source: '.'
diff --git a/vortex-filtering/include/vortex_filtering/utils/ellipse.hpp b/vortex-filtering/include/vortex_filtering/utils/ellipse.hpp
index ea480249..705c17e0 100644
--- a/vortex-filtering/include/vortex_filtering/utils/ellipse.hpp
+++ b/vortex-filtering/include/vortex_filtering/utils/ellipse.hpp
@@ -22,16 +22,16 @@ namespace utils {
 class Ellipse {
 public:
   /** Construct a new Ellipse object
-   * @param center
-   * @param a
-   * @param b
-   * @param angle
+   * @param center center of the ellipse
+   * @param a half the length of the major axis (radius of the circumscribed circle)
+   * @param b half the length of the minor axis (radius of the inscribed circle)
+   * @param angle angle in radians
    */
   Ellipse(const Eigen::Vector2d &center, double a, double b, double angle);
 
   /** Construct a new Ellipse object from a Gaussian
-   * @param gauss
-   * @param scale_factor
+   * @param gauss 2D Gaussian distribution
+   * @param scale_factor scale factor for the ellipse
    */
   Ellipse(const vortex::prob::Gauss2d &gauss, double scale_factor = 1.0);
 
@@ -50,12 +50,12 @@ class Ellipse {
    */
   double y() const;
 
-  /** Get the a parameter of the ellipse
+  /** Get the a parameter of the ellipse (half the length of the major axis)
    * @return double
    */
   double a() const;
 
-  /** Get the b parameter of the ellipse
+  /** Get the b parameter of the ellipse (half the length of the minor axis)
    * @return double
    */
   double b() const;
diff --git a/vortex-filtering/src/utils/ellipse.cpp b/vortex-filtering/src/utils/ellipse.cpp
index 2cf6384a..aef09864 100644
--- a/vortex-filtering/src/utils/ellipse.cpp
+++ b/vortex-filtering/src/utils/ellipse.cpp
@@ -11,8 +11,14 @@ Ellipse::Ellipse(const vortex::prob::Gauss2d &gauss, double scale_factor)
   Eigen::Vector2d eigenValues  = eigenSolver.eigenvalues();
   Eigen::Matrix2d eigenVectors = eigenSolver.eigenvectors();
 
-  a_      = scale_factor * sqrt(eigenValues(1));
-  b_      = scale_factor * sqrt(eigenValues(0));
+  // Sort eigenvalues in descending order
+  if (eigenValues(0) > eigenValues(1)) {
+    std::swap(eigenValues(0), eigenValues(1));
+    eigenVectors.col(0).swap(eigenVectors.col(1));
+  }
+
+  a_      = sqrt(scale_factor * eigenValues(1));
+  b_      = sqrt(scale_factor * eigenValues(0));
   angle_  = atan2(eigenVectors(1, 1), eigenVectors(0, 1));
   center_ = gauss.mean();
 }