From dd0424fb5460a514e22874d2c8bd1151b7d08344 Mon Sep 17 00:00:00 2001
From: Tobias Ribizel <mail@ribizel.de>
Date: Sat, 19 Apr 2025 19:22:20 +0200
Subject: [PATCH 1/2] add copy_to_host function

---
 core/test/base/array.cpp           | 12 +++++++++++-
 include/ginkgo/core/base/array.hpp | 16 +++++++++++++++-
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/core/test/base/array.cpp b/core/test/base/array.cpp
index f7e03855d06..7da2eaa03ac 100644
--- a/core/test/base/array.cpp
+++ b/core/test/base/array.cpp
@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText: 2017 - 2024 The Ginkgo authors
+// SPDX-FileCopyrightText: 2017 - 2025 The Ginkgo authors
 //
 // SPDX-License-Identifier: BSD-3-Clause
 
@@ -219,6 +219,16 @@ TYPED_TEST(Array, CanBeCopiedToExecutorlessArray)
 }
 
 
+TYPED_TEST(Array, CanBeCopiedToHost)
+{
+    std::vector<TypeParam> ref{5, 2};
+
+    auto vec = this->x.copy_to_host();
+
+    ASSERT_EQ(vec, ref);
+}
+
+
 TYPED_TEST(Array, CanBeCopiedFromExecutorlessArray)
 {
     gko::array<TypeParam> a;
diff --git a/include/ginkgo/core/base/array.hpp b/include/ginkgo/core/base/array.hpp
index e0cf8c22ab3..4e4ee9c5f51 100644
--- a/include/ginkgo/core/base/array.hpp
+++ b/include/ginkgo/core/base/array.hpp
@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText: 2017 - 2024 The Ginkgo authors
+// SPDX-FileCopyrightText: 2017 - 2025 The Ginkgo authors
 //
 // SPDX-License-Identifier: BSD-3-Clause
 
@@ -641,6 +641,20 @@ class array {
         }
     }
 
+    /**
+     * Copies the data into an std::vector.
+     *
+     * @return an std::vector containing this array's data.
+     */
+    std::vector<value_type> copy_to_host() const
+    {
+        std::vector<value_type> result(this->get_size());
+        auto view = make_array_view(this->get_executor()->get_master(),
+                                    this->get_size(), result.data());
+        view = *this;
+        return result;
+    }
+
     /**
      * Fill the array with the given value.
      *

From 2b152025584b61e62608dd84d4e82f4a620d6465 Mon Sep 17 00:00:00 2001
From: Tobias Ribizel <mail@ribizel.de>
Date: Tue, 22 Apr 2025 14:07:46 +0200
Subject: [PATCH 2/2] add device copy_to_host test

---
 cuda/test/base/array.cpp | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/cuda/test/base/array.cpp b/cuda/test/base/array.cpp
index db7d4c54536..b2346a91c72 100644
--- a/cuda/test/base/array.cpp
+++ b/cuda/test/base/array.cpp
@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText: 2017 - 2024 The Ginkgo authors
+// SPDX-FileCopyrightText: 2017 - 2025 The Ginkgo authors
 //
 // SPDX-License-Identifier: BSD-3-Clause
 
@@ -58,6 +58,15 @@ TYPED_TEST(Array, CanCopyBackTemporaryCloneOnDifferentExecutor)
 }
 
 
+TYPED_TEST(Array, CanCopyToHost)
+{
+    using T = TypeParam;
+    auto arr = gko::array<T>(this->exec, I<T>{4, 6});
+
+    ASSERT_EQ(arr.copy_to_host(), (std::vector<T>{4, 6}));
+}
+
+
 TYPED_TEST(Array, CanGetValue)
 {
     using T = TypeParam;