Merge pull request #330 from alphaville/fix/ball2

Important bug fix in ball2

CHANGELOG.md

@@ -8,6 +8,17 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 Note: This is the main Changelog file for the Rust solver. The Changelog file for the Python interface (`opengen`) can be found in [/open-codegen/CHANGELOG.md](open-codegen/CHANGELOG.md)
 
 
+<!-- ---------------------
+      v0.8.1
+     --------------------- -->
+## [v0.8.1] - 2023-10-27
+
+### Fixed
+
+- Fix bug in implementation of `ball2.rs` (radius was being ignored for balls centered not at the origin)
+
+
+
 <!-- ---------------------
       v0.8.0
      --------------------- -->
@@ -256,7 +267,8 @@ This is a breaking API change.
      --------------------- -->
 
 <!-- Releases -->
-[v0.7.8]: https://github.com/alphaville/optimization-engine/compare/v0.7.7...v0.8.0
+[v0.8.1]: https://github.com/alphaville/optimization-engine/compare/v0.8.0...v0.8.1
+[v0.8.0]: https://github.com/alphaville/optimization-engine/compare/v0.7.7...v0.8.0
 [v0.7.7]: https://github.com/alphaville/optimization-engine/compare/v0.7.6...v0.7.7 
 [v0.7.6]: https://github.com/alphaville/optimization-engine/compare/v0.7.5...v0.7.6 
 [v0.7.5]: https://github.com/alphaville/optimization-engine/compare/v0.7.4...v0.7.5 

Cargo.toml

@@ -42,7 +42,7 @@ homepage = "https://alphaville.github.io/optimization-engine/"
 repository = "https://github.com/alphaville/optimization-engine"
 
 # Version of this crate (SemVer)
-version = "0.8.0"
+version = "0.8.1"
 
 edition = "2018"
 

src/constraints/ball2.rs

@@ -31,7 +31,7 @@ impl<'a> Constraint for Ball2<'a> {
 
             if norm_difference > self.radius {
                 x.iter_mut().zip(center.iter()).for_each(|(x, c)| {
-                    *x = *c + (*x - *c) / norm_difference;
+                    *x = *c + self.radius * (*x - *c) / norm_difference;
                 });
             }
         } else {

src/constraints/tests.rs

@@ -226,7 +226,7 @@ fn t_rectangle_only_xmax() {
 }
 
 #[test]
-fn t_ball_at_origin() {
+fn t_ball2_at_origin() {
     let radius = 1.0;
     let mut x = [1.0, 1.0];
     let ball = Ball2::new(None, radius);
@@ -246,7 +246,47 @@ fn t_ball_at_origin() {
 }
 
 #[test]
-fn t_ball_elsewhere() {
+fn t_ball2_at_origin_different_radius_outside() {
+    let radius = 0.8;
+    let mut x = [1.0, 1.0];
+    let ball = Ball2::new(None, radius);
+    ball.project(&mut x);
+    let norm_proj_x = crate::matrix_operations::norm2(&x);
+    unit_test_utils::assert_nearly_equal(radius, norm_proj_x, 1e-10, 1e-12, "wrong norm");
+}
+
+#[test]
+fn t_ball2_at_origin_different_radius_inside() {
+    let radius = 0.8;
+    let mut x = [-0.2, 0.15];
+    let ball = Ball2::new(None, radius);
+    ball.project(&mut x);
+    unit_test_utils::assert_nearly_equal_array(&x, &[-0.2, 0.15], 1e-10, 1e-12, "wrong");
+}
+
+#[test]
+fn t_ball2_at_center_different_radius_outside() {
+    let radius = 1.2;
+    let mut x = [1.0, 1.0];
+    let center = [-0.8, -1.1];
+    let ball = Ball2::new(Some(&center), radius);
+    ball.project(&mut x);
+    let norm_x_minus_c = crate::matrix_operations::norm2_squared_diff(&x, &center).sqrt();
+    unit_test_utils::assert_nearly_equal(radius, norm_x_minus_c, 1e-10, 1e-12, "wrong norm");
+}
+
+#[test]
+fn t_ball2_at_center_different_radius_inside() {
+    let radius = 1.2;
+    let mut x = [-0.9, -0.85];
+    let center = [-0.8, -1.1];
+    let ball = Ball2::new(Some(&center), radius);
+    ball.project(&mut x);
+    unit_test_utils::assert_nearly_equal_array(&[-0.9, -0.85], &x, 1e-10, 1e-12, "wrong result");
+}
+
+#[test]
+fn t_ball2_elsewhere() {
     let radius = 1.0;
     let center = [1.0, 1.0];
     let mut x = [2.0, 2.0];
@@ -465,7 +505,7 @@ fn t_cartesian_product_dimension() {
 #[test]
 fn t_cartesian_ball_no_constraint() {
     let xc = [1., 0., 0.];
-    let radius = 0.5;
+    let radius = 1.0;
     let ball2 = Ball2::new(Some(&xc), radius);
     let no_constraints = NoConstraints::new();
     let cartesian = CartesianProduct::new_with_capacity(4)