Add Changelog entry.

Author: kellertuer

Changelog.md

@@ -6,6 +6,12 @@ The file was started with Version `0.4`.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.6.1] unreleased
+
+### Added
+
+* the [gradient sampling algorithm](https://manoptjl.org/stable/solvers/gradient_sampling/) based on the paper by [Hosseini and Uschmajew](https://doi.org/10.1137/16m1069298) (#618)
+
 ## [0.6.0] June 24, 2026
 
 This is a breaking change since the JuMP extension is dropped.

src/solvers/gradient_sampling.jl

@@ -64,7 +64,7 @@ $(_args(:M))
 $(_args(:sub_problem))
 $(_args(:sub_state))
 
-## Keyowrd arguments
+## Keyword arguments
 
 $(_kwargs(:p; add_properties = [:as_Initial]))
 $(_kwargs(:retraction_method))
@@ -250,7 +250,7 @@ $(_note(:GradientObjective))
 $(_kwargs(:differential))
 $(_kwargs(:evaluation; add_properties = [:GradientExample]))
 $(_kwargs(:retraction_method))
-* `sample_size = 5` set the number of sampling points. If you initialise `sampled_points`, `sampled_vectors`, and `convex_hull_coeffs` directly
+* `sample_size = `$(_link(:manifold_dimension))`+1` set the number of sampling points. If you initialise `sampled_points`, `sampled_vectors`, and `convex_hull_coeffs` directly
   this parameter has no effect.
 * `sampling_radius = 0.5`
 * `sampling_radius_reduction = 0.5`
@@ -307,7 +307,7 @@ end
 function gradient_sampling!(
         M::AbstractManifold, mgo::O, p;
         X = zero_vector(M, p),
-        sample_size::Int = 5,
+        sample_size::Int = manifold_dimension(M)+1,
         convex_hull_coeffs::AbstractVector = [0.0 for _ in 1:(sample_size + 1)],
         retraction_method::AbstractRetractionMethod = default_retraction_method(M, typeof(p)),
         sampled_points::AbstractVector = [copy(M, p) for _ in 1:(sample_size + 1)],

test/solvers/test_gradient_sampling.jl

@@ -20,14 +20,13 @@ grad_f(M, p) = sum(1 / d * grad_distance.(Ref(M), data, Ref(p)))
 m1 = gradient_descent(
     M, f, grad_f, p0;
     return_state = true,
-    debug = _debug_gradient_sampling ? [:Iteration, :Cost, " ", :Stepsize, " ", :GradientNorm, "\n", :Stop] : [],
     record = [:Iteration, :Cost, RecordGradientNorm()]
 );
 
 m2 = gradient_sampling(
     M, f, grad_f, p0;
     return_state = true,
-    debug = _debug_gradient_sampling ? [:Iteration, :Cost, " ", :Stepsize, " ", :GradientNorm, " ", :Change, "\n", :Stop] : [],
+    debug = _debug_gradient_sampling ? [:Iteration, :Cost, " ", :subgradient_norm_tolerance, " ", :sampling_radius, " | ", :GradientNorm, " ", :Change, "\n", :Stop, 100] : [],
     record = [:Iteration, :Cost, RecordGradientNorm()]
 )