F2PY changing integers to arrays???

[mwojc]

john wrote:

> I have a simple module which performs basic operations on plot3d files
> (below).  I wrapped like:
> 
> f2py --fcompiler=gfortran -m plot3d -c prec.f90 plot3d.f90
> 
> That seems to work fine, but i get some unexpected results...
> 
>>>> from plot3d import plot3d as p3
>>>> dir(p3)
> ['imax', 'jmax', 'kmax', 'mg', 'prc', 'printall', 'readit', 'writeit',
> 'writeit2d']
>>>> p3.readit( "mesh.xrtz.dat", "FORMATTED", ".TRUE." )
>>>> p3.imax
> array(409)
> 
> 
> "409" is correct, but "imax" is declared as an INTEGER in fortran and
> now it's an array in python???  Any ideas?
> 
> 
> 
> 
> 
> 
> 
> 
> # prec.f90
> MODULE prec
> IMPLICIT NONE
> INTEGER, PARAMETER :: single = SELECTED_REAL_KIND(p=6,r=37)
> INTEGER, PARAMETER :: double = SELECTED_REAL_KIND(p=15,r=200)
> END MODULE prec
> 
> 
> 
> 
> # plot3d.f90
> MODULE PLOT3D
> USE prec
> IMPLICIT NONE
> INTEGER, PARAMETER :: prc=single
> REAL(prc), ALLOCATABLE, DIMENSION(:,:,:,:) :: x, y, z
> INTEGER :: mg, imax, jmax, kmax
> 
> CONTAINS
> 
> !----------
>     SUBROUTINE READIT( fname, ftype, fmg )
>     ! reads the plot3d, formatted, mg file in xyz
>     IMPLICIT NONE
>     CHARACTER(len=20), INTENT(IN) :: fname, ftype
> 
>     LOGICAL :: fmg
>     INTEGER :: i, j, k, n, f=1
> 
>     SELECT CASE (ftype)
>         CASE ('FORMATTED')
>             OPEN( UNIT=f, FILE=fname, STATUS='OLD', ACTION='READ',
> FORM=ftype )
>             IF (fmg) READ(f,*) mg ! only read if multigrid
>             READ(f,*) imax, jmax, kmax
>             ALLOCATE( x(mg, imax, jmax, kmax) )
>             ALLOCATE( y(mg, imax, jmax, kmax) )
>             ALLOCATE( z(mg, imax, jmax, kmax) )
>             READ(f,*) ((((x(n,
> i,j,k),i=1,imax),j=1,jmax),k=1,kmax),n=1,mg), &
>                       ((((y(n,
> i,j,k),i=1,imax),j=1,jmax),k=1,kmax),n=1,mg), &
>                       ((((z(n,
> i,j,k),i=1,imax),j=1,jmax),k=1,kmax),n=1,mg)
>         CASE ('UNFORMATTED')
>             OPEN( UNIT=f, FILE=fname, STATUS='OLD', ACTION='READ',
> FORM=ftype )
>             IF (fmg) READ(f) mg ! only read if multigrid
>             READ(f) imax, jmax, kmax
>             ALLOCATE( x(mg, imax, jmax, kmax) )
>             ALLOCATE( y(mg, imax, jmax, kmax) )
>             ALLOCATE( z(mg, imax, jmax, kmax) )
>             READ(f) ((((x(n,
> i,j,k),i=1,imax),j=1,jmax),k=1,kmax),n=1,mg), &
>                     ((((y(n,
> i,j,k),i=1,imax),j=1,jmax),k=1,kmax),n=1,mg), &
>                     ((((z(n,
> i,j,k),i=1,imax),j=1,jmax),k=1,kmax),n=1,mg)
>         CASE DEFAULT
>             WRITE(*,*) 'filetype not supported in <PLOT3D.READIT>'
>             STOP
>     END SELECT
> 
>     CLOSE(f)
> 
>     END SUBROUTINE READIT
> 
> END MODULE PLOT3D

I'm not sure why you obtain array(409) instead 409, but you can use this
type in python as normal integer. For example array(409)+409 gives integer
value 818. 

Greetings
-- 
Marek