message: Fixed the same error in the conversion from dense to sellp for omp.
diff: @@ -282,7 +282,8 @@ void convert_to_sellp(std::shared_ptr<const OmpExecutor> exec,
  for (size_type slice = 0; slice < slice_num; slice++) {
  if (slice > 0) {
  - slice_sets[slice] = slice_lengths[slice - 1];
  + slice_sets[slice] =
  + slice_sets[slice - 1] + slice_lengths[slice - 1];
  }
  size_type current_slice_length = 0;
  #pragma omp parallel for reduction(max : current_slice_length)
  @@ -325,7 +326,8 @@ void convert_to_sellp(std::shared_ptr<const OmpExecutor> exec,
  }
  }
  - slice_sets[slice_num] = slice_lengths[slice_num - 1];
  + slice_sets[slice_num] =
  + slice_sets[slice_num - 1] + slice_lengths[slice_num - 1];
  }
  GKO_INSTANTIATE_FOR_EACH_VALUE_AND_INDEX_TYPE(
  