I have a derived type with a pointer to an array of a second derived type
TYPE vertex
REAL :: x, y, z
END TYPE
TYPE path
TYPE(vertex), DIMENSION(:), POINTER :: vertices => NULL()
END TYPE
The intent is to make the vertices array resizable so that any number of vertex points can be added to the array. I have created code to append a vertex to that pointer.
SUBROUTINE path_append_vertex(this, x, y, z)
IMPLICIT NONE
!-------------------------------------------------------------------------------
! Variable declarations.
!-------------------------------------------------------------------------------
TYPE(path), INTENT(inout) :: this
REAL, INTENT(in) :: x, y, z
!-------------------------------------------------------------------------------
! Local Variable declarations.
!-------------------------------------------------------------------------------
INTEGER :: status
TYPE(vertex), DIMENSION(:), ALLOCATABLE :: vertices
!-------------------------------------------------------------------------------
! Start of executable code
!-------------------------------------------------------------------------------
IF (ASSOCIATED(this%vertices)) THEN
! Create a temporary array the same size as current number of vertices. Copy the
! contents of the old array to the new array then delete the old array.
ALLOCATE(vertices(SIZE(this%vertices)), STAT = status)
CALL check_status(status)
vertices = this%vertices
DEALLOCATE(this%vertices)
! Create a new array with one extra element. Copy the contents of the temporary
! array to the new one the delete the temporary array.
ALLOCATE(this%vertices(SIZE(vertices) + 1), STAT = status)
CALL check_status(status)
this%vertices(1:SIZE(vertices)) = vertices
DEALLOCATE(vertices)
this%vertices(SIZE(this%vertices))%x = x
this%vertices(SIZE(this%vertices))%y = y
this%vertices(SIZE(this%vertices))%z = z
ELSE
ALLOCATE(this%vertices(1), STAT = status)
CALL check_status(status)
this%vertices(1)%x = x
this%vertices(1)%y = y
this%vertices(1)%z = z
ENDIF
END SUBROUTINE
I create a few path objects.
TYPE ipch_desc
...
TYPE(path) :: chordPath
END TYPE
SUBROUTINE ipch_desc_construct(this, ...)
...
TYPE (ipch_desc), INTENT(inout) :: this
...
! Must NULL out the vertices array or else it will point to the last
! integration_path created in memory. Not sure why these are defaulting
! to NULL
this%chordPath%vertices => NULL()
CALL path_append_vertex(this%chordPath, xcart_i(1), xcart_i(2), xcart_i(3))
CALL path_append_vertex(this%chordPath, xcart_f(1), xcart_f(2), xcart_f(3))
! Check the value of the path vertices.
write(*,*) this%chordPath%vertices
END SUBROUTINE
Everything work all well and good and I get the correct values for each vertex. For instance for three path objects created I get
-0.33808113528699218 1.0467574437103653 0.10713720000000000 -0.16057879084545851 0.49717960298733294 0.10713720000000000
-0.33322243268266594 1.0483142707971911 1.42240000000000010E-003 -0.14945358419461796 0.47017940500485894 1.42240000000000010E-003
-0.33656460666251325 1.0472460386853264 -0.10629900000000000 -0.15821659220752302 0.49230280357365630 -0.10629900000000000
When using these path objects latter in the code,
SUBROUTINE ipch_mc_model_compute(a_ipch, ...)
...
TYPE (ipch_desc), INTENT (inout) :: a_ipch
...
! Check the value of the path vertices again.
write(*,*) a_ipch%chordPath%vertices
...
END SUBROUTINE
only the first N-1 values remain correct. For the same values created above I get,
-0.33808113528699218 1.0467574437103653 0.10713720000000000 -0.16057879084545851 0.49717960298733294 0.10713720000000000
-0.33322243268266594 1.0483142707971911 1.42240000000000010E-003 -0.14945358419461796 0.47017940500485894 1.42240000000000010E-003
0.15094203233057696 6.94277920927416864E-310 -0.10629900000000000 1.63041663127611360E-322 3.01884064661153912E-003 6.94277920927179713E-310
Regardless of the number of path objects I create, the Nth always ends up with wrong values. What could be causing this?
I figured out where the problem was. The ipch_desc object was being constructed to a temp then assigned to an element in an array.
ipch_desc_arr(icount_chords) = ipch_desc_temp
I will either need to remove this temporary or over load the default assignment operators to fix it.