linear_operator_mod.F90

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! Copyright (c) 2017,  Met Office, on behalf of HMSO and Queen's Printer
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!> @brief Abstract base type for linear operator
!> @detail Implements an abstract class for a linear operator which
!! defines an interface for the linear operator application y = A.x

module linear_operator_mod
  use constants_mod, only : i_def, r_def
  use vector_mod,    only : abstract_vector_type
  implicit none
  private

  !>@brief Abstract linear operator type to define interfaces for the solver API
  type, public, abstract :: abstract_linear_operator_type
     private
   contains
     procedure (apply_interface), deferred :: apply
  end type abstract_linear_operator_type

  abstract interface
     !> Asbtract interface defined for the apply method.
     !> param[in] self a linear operator
     !> param[in] x a vector the linear operator is applied to
     !> param[inout] y a vector, the result.
     subroutine apply_interface(self, x, y)
       import :: abstract_linear_operator_type
       import :: abstract_vector_type
       class(abstract_linear_operator_type), intent(in)    :: self
       class(abstract_vector_type),          intent(in)    :: x
       class(abstract_vector_type),          intent(inout) :: y
     end subroutine apply_interface
  end interface
end module linear_operator_mod