Is there a way to overload the =
operator so that you can write an assignment like in this example:
module constants_mod
integer,parameter :: dpn = selected_real_kind(14)
end module
module vectorField_mod
use constants_mod
implicit none
private
public :: vectorField
public :: allocateX,allocateY,allocateZ
public :: delete
! public :: operator(=)
type vectorField
integer,dimension(3) :: sx,sy,sz
real(dpn),dimension(:,:,:),allocatable :: x,y,z
end type
interface delete
module procedure deallocateVectorField
end interface
! interface operator (=)
! module procedure vectorAssign
! end interface
contains
! function vectorAssign(f) result(q)
! implicit none
! real(dpn),intent(in) :: f
! type(vectorField) :: q
! q%x = f; q%y = f; q%z = f
! end function
! subroutine vectorAssign(f,g)
! implicit none
! type(vectorField),intent(inout) :: f
! real(dpn),intent(in) :: g
! f%x = g; f%y = g; f%z = g
! end subroutine
subroutine allocateX(field,Nx,Ny,Nz)
implicit none
type(vectorField),intent(inout) :: field
integer,intent(in) :: Nx,Ny,Nz
if (allocated(field%x)) deallocate(field%x)
allocate(field%x(Nx,Ny,Nz))
field%sx = shape(field%x)
end subroutine
subroutine allocateY(field,Nx,Ny,Nz)
implicit none
type(vectorField),intent(inout) :: field
integer,intent(in) :: Nx,Ny,Nz
if (allocated(field%y)) deallocate(field%y)
allocate(field%y(Nx,Ny,Nz))
field%sy = shape(field%y)
end subroutine
subroutine allocateZ(field,Nx,Ny,Nz)
implicit none
type(vectorField),intent(inout) :: field
integer,intent(in) :: Nx,Ny,Nz
if (allocated(field%z)) deallocate(field%z)
allocate(field%z(Nx,Ny,Nz))
field%sz = shape(field%z)
end subroutine
subroutine deallocateVectorField(field)
implicit none
type(vectorField),intent(inout) :: field
deallocate(field%x,field%y,field%z)
field%sx = 0; field%sy = 0; field%sz = 0
end subroutine
end module
program test
use constants_mod
use vectorField_mod
implicit none
type(vectorField) :: a
integer :: N = 1
real(dpn) :: dt = 0.1
call allocateX(a,N,N,N)
call allocateY(a,N,N,N)
call allocateZ(a,N,N,N)
a%x = dble(1.0) ! want to avoid this
a%y = dble(1.0) ! want to avoid this
a%z = dble(1.0) ! want to avoid this
a = real(1.0,dpn) ! want this instead (does not compile)
call delete(a)
end program
I've tried two different ways (shown in comments) but I get errors saying that there is a syntax error in generic specification (for publicizing the =
operator).
=
is not an operator, it is an assignment in Fortran and they are very different beasts.
To the classical possibility found in Fortran 90 and explained well in other answers, Fortran 2003 added a better possibility to bind the overloaded operators and assignments with the derived type.
This way you are sure you will not import the type without the assignment (beware of public and private statement in this case!). It can have very unpleasant consequences and can be hard to debug:
type vectorField
integer,dimension(3) :: sx,sy,sz
real(dpn),dimension(:,:,:),allocatable :: x,y,z
contains
procedure :: assignVector
generic :: assignment(=) => assignVector
end type
This way you do not have to be that careful to not forget the public :: assignment (=)
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With