! This file: http://ftp.aset.psu.edu/pub/ger/fortran/hdk/dyn7.f90
!
!=== Example of Allocatable (DP 2-D) array.
      integer ierror, MB, na, nb
        double precision a
        allocatable a
        dimension a(:,:)
        print*, "How many MB to Allocate?"
        read(unit=*,fmt=*) na
        MB=1024**2
!---DOUBLE PRECISION array assumed to have 8-byte elements.
        nb=MB/8
        allocate( a(na,nb), stat=ierror)
        if (ierror.ne.0) then
          print *, "?? Cannot allocate',na,'MB of virtual storage."
          print *, "At least this much free disk space for swap file",   &
                        " is needed."
          stop
        endif
!---Initialize all elements of that array (for example's sake here).
        call anysub(a, na,nb)
!---Deallocate the array and quit.
        deallocate( a)
        print *, "Double Presion Array of dimension (",na,",",nb,")"
        print *, "was succesfully allocated, used, and deallocated."
        end
   subroutine anysub(a, n1,n2)
        integer i,j,n1,n2
        double precision a(n1,n2)
!---Access the array in row major order - by columns - (least paging).
        do  j=1,n2
          do  i=1,n1
           a(i,j)=i+j
          end do
       end do
        end