Memory release problem

[wdliu]

Hi,
We are running the latest Intel Compiler (v. 8.1.2380.2003) and encountering a memory release problem. It would be greatly appreciated if anyone can shed some light on this problem.

Bellow is the code. Test was done on a Dell box with 2GB physical memory.

Following an allocation of a small space (~500MB), a second call was trying to allocate more space (~1.8GB). It failed out-of-space, because the first allocated space was not released properly still reserved. The code, however, runs perfect under some other values of n and m.

Thanks in advance

David
--------------------------------------------------------

program main
implicit none
integer :: n, m, more
!
! n is the number of integer_pointers which will be allocated
! m is the total allocation size (each pointer is dimensioned m/n)
!
! For m = 200000000
! n = 1000 is OK
! n = 2000 does not release memory
!
! For n = 2000
! m = 10000000 does not release memory
! m = 50000000 does not release memory
! m = 100000000 does not release memory
! m = 200000000 does not release memory
! m = 300000000 is OK
! m = 400000000 is OK
!
n = 1000 ! number of integer_pointers
m = 130000000 ! total allocation size
call alloc(n,m)
call more_allocs() ! allocates 1.8GB
!
end program main

subroutine alloc(n,m)
implicit none
integer, intent(in) :: n, m
!
type integer_pointer
integer, pointer :: i(:) => null()
end type integer_pointer
type (integer_pointer), dimension(:),allocatable :: a
!
integer :: i, nsize, ierr
!
! If nsize > 130000, this works OK
!
nsize = m/n
allocate(a(n),stat = ierr)
do i = 1, n
allocate(a(i)%i(nsize),stat = ierr)
if(ierr /= 0)return
a(i)%i = 1
end do
do i = n, 1, -1
if(associated(a(i)%i))deallocate(a(i)%i)
nullify(a(i)%i)
end do
deallocate(a)

end subroutine

subroutine more_allocs()
implicit none
!
type integer_pointer
integer, pointer :: i(:) => null()
end type integer_pointer
type (integer_pointer), dimension(:),allocatable :: a
!
integer :: i, n, nsize, ierr
!
nsize = 200000
n = 2250
allocate(a(n),stat = ierr)
do i = 1, n
allocate(a(i)%i(nsize),stat = ierr)
if(ierr /= 0)then
write(*,*)"Out of space"
return
endif
a(i)%i = 1
end do
do i = n, 1, -1
deallocate(a(i)%i)
nullify(a(i)%i)
end do
deallocate(a)
!
end subroutine more_allocs

Message Edited by wdliu on 11-10-2004 09:29 AM