message: Add default argument for PetscParMatrix constructor out of a HypreParMatrix or a general Operator
diff: @@ -181,7 +181,7 @@ public:
  PETSc format @a tid. */
  /** The supported type ids are: Operator::PETSC_MATAIJ,
  Operator::PETSC_MATIS, and Operator::PETSC_MATSHELL. */
  - PetscParMatrix(const HypreParMatrix *ha, Operator::Type tid);
  + PetscParMatrix(const HypreParMatrix *ha, Operator::Type tid = Operator::PETSC_MATAIJ);
  /** @brief Convert an mfem::Operator into a PetscParMatrix in the given PETSc
  format @a tid. */
  @@ -196,7 +196,7 @@ public:
  created using @a tid as the type for the blocks.
  Note that if @a op is already a PetscParMatrix of the same type as
  @a tid, the resulting PetscParMatrix will share the same Mat object */
  - PetscParMatrix(MPI_Comm comm, const Operator *op, Operator::Type tid);
  + PetscParMatrix(MPI_Comm comm, const Operator *op, Operator::Type tid = Operator::PETSC_MATSHELL);
  /// Creates block-diagonal square parallel matrix.
  /** The block-diagonal is given by @a diag which must be in CSR format
  