Add array::copy_to_host function

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;

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;

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.
      *