Add sparse matrix usage to example

Author: Xewar313

scripts/build_run.sh

@@ -16,3 +16,4 @@ mpirun -n 3 ./build/src/example3
 mpirun -n 3 ./build/src/example4
 mpirun -n 3 ./build/src/example5
 mpirun -n 3 ./build/src/example6
+mpirun -n 3 ./build/src/example7

src/CMakeLists.txt

@@ -41,3 +41,8 @@ add_executable(example6 example6.cpp)
 
 target_compile_definitions(example6 INTERFACE DR_FORMAT)
 target_link_libraries(example6 DR::mpi fmt::fmt)
+
+add_executable(example7 example7.cpp)
+
+target_compile_definitions(example7 INTERFACE DR_FORMAT)
+target_link_libraries(example7 DR::mpi fmt::fmt)

src/example7.cpp

@@ -0,0 +1,59 @@
+// SPDX-FileCopyrightText: Intel Corporation
+//
+// SPDX-License-Identifier: BSD-3-Clause
+
+#include <dr/mp.hpp>
+#include <fmt/core.h>
+
+
+/* Sparse band matrix vector multiplication */
+int main() {
+  dr::mp::init(sycl::default_selector_v);
+  using I = long;
+  using V = double;
+  dr::views::csr_matrix_view<V, I> local_data;
+  auto root = 0;
+  auto n = 10;
+  auto up = 1; // number of diagonals above main diagonal
+  auto down = up; // number of diagonals below main diagonal
+  if (root == dr::mp::rank()) {
+     local_data = dr::generate_band_csr<V, I>(n, up, down);
+  }
+
+  dr::mp::distributed_sparse_matrix<
+      V, I, dr::mp::MpiBackend,
+      dr::mp::csr_eq_distribution<V, I, dr::mp::MpiBackend>>
+      matrix(local_data, root);
+
+  std::vector<double> b;
+  b.reserve(matrix.shape().second);
+  std::vector<double> res(matrix.shape().first);
+  for (auto i = 0; i < matrix.shape().second; i++) {
+    b.push_back(i);
+  }
+
+  dr::mp::broadcasted_vector<double> broadcasted_b;
+  broadcasted_b.broadcast_data(matrix.shape().second, 0, b,
+                             dr::mp::default_comm());
+
+  gemv(root, res, matrix, broadcasted_b);
+
+  if (root == dr::mp::rank()) {
+    fmt::print("Band matrix {} x {} with bandwitch {}\n", n, n, up * 2);
+    fmt::print("Input: ");
+    for (auto x: b) {
+        fmt::print("{} ", x);
+    }
+    fmt::print("\n");
+    fmt::print("Matrix vector multiplication res: ");
+    for (auto x: res) {
+        fmt::print("{} ", x);
+    }
+    fmt::print("\n");
+
+  }
+
+  dr::mp::finalize();
+
+  return 0;
+}