message: fix omp kernel implementation
diff: @@ -34,6 +34,9 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  #include "core/matrix/dense_kernels.hpp"
  +#include <algorithm>
  +
  +
  #include <omp.h>
  @@ -45,7 +48,6 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  #include <ginkgo/core/matrix/hybrid.hpp>
  #include <ginkgo/core/matrix/sellp.hpp>
  -#include <algorithm>
  namespace gko {
  namespace kernels {
  @@ -302,10 +304,9 @@ void convert_to_ell(std::shared_ptr<const OmpExecutor> exec,
  result->col_at(j, i) = 0;
  }
  }
  - size_type col_idx = 0;
  #pragma omp parallel for
  for (size_type row = 0; row < num_rows; row++) {
  - col_idx = 0;
  + size_type col_idx = 0;
  for (size_type col = 0; col < num_cols; col++) {
  auto val = source->at(row, col);
  if (val != zero<ValueType>()) {
  @@ -365,7 +366,8 @@ void convert_to_hybrid(std::shared_ptr<const OmpExecutor> exec,
  size_type coo_idx = 0;
  #pragma omp parallel for
  for (size_type row = 0; row < num_rows; row++) {
  - size_type col_idx = 0, col = 0;
  + size_type col_idx = 0;
  + size_type col = 0;
  while (col < num_cols && col_idx < ell_lim) {
  auto val = source->at(row, col);
  if (val != zero<ValueType>()) {
  