message: Use cuSPARSE CSR by default
diff: @@ -406,8 +406,7 @@ protected:
  */
  Csr(std::shared_ptr<const Executor> exec, const dim<2> &size = dim<2>{},
  size_type num_nonzeros = {},
  - std::shared_ptr<strategy_type> strategy =
  - std::make_shared<automatical>())
  + std::shared_ptr<strategy_type> strategy = std::make_shared<cusparse>())
  : EnableLinOp<Csr>(exec, size),
  values_(exec, num_nonzeros),
  col_idxs_(exec, num_nonzeros),
  @@ -441,8 +440,7 @@ protected:
  typename RowPtrsArray>
  Csr(std::shared_ptr<const Executor> exec, const dim<2> &size,
  ValuesArray &&values, ColIdxsArray &&col_idxs, RowPtrsArray &&row_ptrs,
  - std::shared_ptr<strategy_type> strategy =
  - std::make_shared<automatical>())
  + std::shared_ptr<strategy_type> strategy = std::make_shared<cusparse>())
  : EnableLinOp<Csr>(exec, size),
  values_{exec, std::forward<ValuesArray>(values)},
  col_idxs_{exec, std::forward<ColIdxsArray>(col_idxs)},
  