basic manifold diff sandbox test

Author: dehann

test/manifolds/manifolddiff.jl

@@ -0,0 +1,43 @@
+
+# using Revise
+using Test
+using LinearAlgebra
+using Manifolds, Manopt
+using FiniteDifferences, ManifoldDiff
+
+##
+
+@testset "ManifoldDiff, Basic test" begin
+##
+
+# finitediff setup
+r_backend = ManifoldDiff.TangentDiffBackend(
+    ManifoldDiff.FiniteDifferencesBackend()
+)
+
+# problem setup
+n = 100
+σ = π / 8
+M = Sphere(2)
+p = 1 / sqrt(2) * [1.0, 0.0, 1.0]
+data = [exp(M, p,  σ * rand(M; vector_at=p)) for i in 1:n];
+
+# objective function
+f(M, p) = sum(1 / (2 * n) * distance.(Ref(M), Ref(p), data) .^ 2)
+f_(p) = f(M,p)
+
+# manual gradient
+# grad_f(M, p) = sum(1 / n * grad_distance.(Ref(M), data, Ref(p)));
+
+# non-manual: intrinsic finite differences gradient
+grad_f_FD(M,p) = ManifoldDiff.gradient(M, f_, p, r_backend)
+
+# and solve
+m1 = gradient_descent(M, f, grad_f_FD, data[1])
+
+@test isapprox(p, m1; atol=0.15)
+
+##
+end
+
+##

test/runtests.jl

@@ -18,6 +18,7 @@ include("testEuclidDistance.jl")
 include("testSphereMani.jl")
 include("testSpecialOrthogonalMani.jl")
 include("testBasicManifolds.jl")
+include("manifolds/manifolddiff.jl")
 
 # start as basic as possible and build from there
 include("typeReturnMemRef.jl")