wip: use row-scatterer type

Author: MarcelKoch

core/CMakeLists.txt

@@ -82,6 +82,7 @@ target_sources(${ginkgo_core}
     matrix/identity.cpp
     matrix/permutation.cpp
     matrix/row_gatherer.cpp
+    matrix/row_scatterer.cpp
     matrix/scaled_permutation.cpp
     matrix/sellp.cpp
     matrix/sparsity_csr.cpp

core/matrix/row_scatterer.cpp

@@ -0,0 +1,37 @@
+// SPDX-FileCopyrightText: 2024 The Ginkgo authors
+//
+// SPDX-License-Identifier: BSD-3-Clause
+
+#include "ginkgo/core/matrix/row_scatterer.hpp"
+
+namespace gko {
+namespace matrix {
+
+
+template <typename IndexType>
+RowScatterer<IndexType>::RowScatterer(std::shared_ptr<const Executor> exec)
+    : EnableLinOp<RowScatterer>(std::move(exec))
+{}
+
+
+template <typename IndexType>
+RowScatterer<IndexType>::RowScatterer(std::shared_ptr<const Executor> exec,
+                                      array<IndexType> idxs, size_type to_size)
+    : EnableLinOp<RowScatterer>(exec, {to_size, idxs.get_size()}),
+      idxs_(exec, std::move(idxs))
+{}
+
+
+template <typename IndexType>
+void RowScatterer<IndexType>::apply_impl(const LinOp* b, LinOp* x) const
+{}
+
+
+template <typename IndexType>
+void RowScatterer<IndexType>::apply_impl(const LinOp* alpha, const LinOp* b,
+                                         const LinOp* beta, LinOp* x) const
+{}
+
+
+}  // namespace matrix
+}  // namespace gko

include/ginkgo/core/matrix/row_scatterer.hpp

@@ -0,0 +1,45 @@
+// SPDX-FileCopyrightText: 2024 The Ginkgo authors
+//
+// SPDX-License-Identifier: BSD-3-Clause
+
+#pragma once
+
+#include <ginkgo/core/base/lin_op.hpp>
+
+namespace gko {
+
+namespace matrix {
+
+
+template <typename IndexType = int32>
+class RowScatterer : public EnableLinOp<RowScatterer<IndexType>> {
+    friend class EnablePolymorphicObject<RowScatterer>;
+
+public:
+    static std::unique_ptr<RowScatterer> create(
+        std::shared_ptr<const Executor> exec, array<IndexType> idxs,
+        size_type to_size)
+    {
+        return std::unique_ptr<RowScatterer>(
+            new RowScatterer(std::move(exec), std::move(idxs), to_size));
+    }
+
+protected:
+    void apply_impl(const LinOp* b, LinOp* x) const override;
+
+    void apply_impl(const LinOp* alpha, const LinOp* b, const LinOp* beta,
+                    LinOp* x) const override;
+
+private:
+    explicit RowScatterer(std::shared_ptr<const Executor> exec);
+
+    explicit RowScatterer(std::shared_ptr<const Executor> exec,
+                          array<IndexType> idxs, size_type to_size);
+
+    array<IndexType> idxs_;
+};
+
+
+}  // namespace matrix
+
+}  // namespace gko

include/ginkgo/ginkgo.hpp

@@ -105,6 +105,7 @@
 #include <ginkgo/core/matrix/identity.hpp>
 #include <ginkgo/core/matrix/permutation.hpp>
 #include <ginkgo/core/matrix/row_gatherer.hpp>
+#include <ginkgo/core/matrix/row_scatterer.hpp>
 #include <ginkgo/core/matrix/scaled_permutation.hpp>
 #include <ginkgo/core/matrix/sellp.hpp>
 #include <ginkgo/core/matrix/sparsity_csr.hpp>