From 22aaf3a1abdd06aff25ba44248218ef5bb6ff94f Mon Sep 17 00:00:00 2001
From: Mateusz Baran <mateuszbaran89@gmail.com>
Date: Tue, 10 Oct 2023 16:04:45 +0200
Subject: [PATCH] tests for Sasaki retraction

---
 src/point_vector_fallbacks.jl | 20 ++++++++++++++++++++
 src/retractions.jl            |  9 +++++++++
 test/default_manifold.jl      | 11 +++++++++++
 3 files changed, 40 insertions(+)

diff --git a/src/point_vector_fallbacks.jl b/src/point_vector_fallbacks.jl
index 5b36dab5..797e67cb 100644
--- a/src/point_vector_fallbacks.jl
+++ b/src/point_vector_fallbacks.jl
@@ -331,6 +331,26 @@ macro default_manifold_fallbacks(TM, TP, TV, pfield::Symbol, vfield::Symbol)
                 ManifoldsBase.retract_embedded!(M, q.$pfield, p.$pfield, X.$vfield, t, m)
                 return q
             end
+            function ManifoldsBase.retract_sasaki(
+                M::$TM,
+                p::$TP,
+                X::$TV,
+                t::Number,
+                m::SasakiRetraction,
+            )
+                return $TP(ManifoldsBase.retract_sasaki(M, p.$pfield, X.$vfield, t, m))
+            end
+            function ManifoldsBase.retract_sasaki!(
+                M::$TM,
+                q::$TP,
+                p::$TP,
+                X::$TV,
+                t::Number,
+                m::SasakiRetraction,
+            )
+                ManifoldsBase.retract_sasaki!(M, q.$pfield, p.$pfield, X.$vfield, t, m)
+                return q
+            end
         end,
     )
     for f_postfix in [:polar, :project, :qr, :softmax]
diff --git a/src/retractions.jl b/src/retractions.jl
index ea74671e..62071e06 100644
--- a/src/retractions.jl
+++ b/src/retractions.jl
@@ -1074,6 +1074,15 @@ retract_softmax!(M::AbstractManifold, q, p, X, t::Number)
 
 function retract_softmax! end
 
+"""
+    retract_sasaki!(M::AbstractManifold, q, p, X, t::Number, m::SasakiRetraction)
+
+Compute the in-place variant of the [`SasakiRetraction`](@ref) `m`.
+"""
+retract_pade!(M::AbstractManifold, q, p, X, t::Number, m::SasakiRetraction)
+
+function retract_sasaki! end
+
 @doc raw"""
     retract(M::AbstractManifold, p, X, method::AbstractRetractionMethod=default_retraction_method(M, typeof(p)))
     retract(M::AbstractManifold, p, X, t::Number=1, method::AbstractRetractionMethod=default_retraction_method(M, typeof(p)))
diff --git a/test/default_manifold.jl b/test/default_manifold.jl
index 73e34b3f..4c8c1e22 100644
--- a/test/default_manifold.jl
+++ b/test/default_manifold.jl
@@ -181,6 +181,16 @@ function ManifoldsBase.retract_exp_ode!(
     return (q .= p .+ t .* X)
 end
 ManifoldsBase.retract_pade!(::DefaultManifold, q, p, X, t::Number, i) = (q .= p .+ t .* X)
+function ManifoldsBase.retract_sasaki!(
+    ::DefaultManifold,
+    q,
+    p,
+    X,
+    t::Number,
+    ::SasakiRetraction,
+)
+    return (q .= p .+ t .* X)
+end
 ManifoldsBase.retract_softmax!(::DefaultManifold, q, p, X, t::Number) = (q .= p .+ t .* X)
 ManifoldsBase.get_embedding(M::DefaultManifold) = M # dummy embedding
 ManifoldsBase.inverse_retract_polar!(::DefaultManifold, Y, p, q) = (Y .= q .- p)
@@ -723,6 +733,7 @@ Base.size(x::MatrixVectorTransport) = (size(x.m, 2),)
             ODEExponentialRetraction(PolarRetraction(), DefaultBasis()),
             PadeRetraction(2),
             EmbeddedRetraction(ExponentialRetraction()),
+            SasakiRetraction(5),
         ]
             @test retract(M, q, Y, retr) == DefaultPoint(q.value + Y.value)
             @test retract(M, q, Y, 0.5, retr) == DefaultPoint(q.value + 0.5 * Y.value)