[Numpy-discussion] F2PY and multi-dimension arrays - unexpected array size error

Backing Olof olof.backing at combitech.se
Tue Feb 3 12:51:37 EST 2015


Hi
I am helping out with a Python and Fortran project. Let me give you some background:

* Fortran source:
C Bergstrom FCC
C User subroutine VUMAT
      subroutine VUMAT(
C Read only -
     *     nblock, ndir, nshr, nstatev, nprops,
     *     stepTime, dt,
     *     props,
     *     density, strainInc,
     *     tempOld,
     *     stressOld, stateOld, enerInternOld, enerInelasOld,
C Write only -
     *     stressNew, stateNew, enerInternNew, enerInelasNew )
C
      include 'vaba_param.inc'
C
      dimension props(nprops),
     1     density(nblock), strainInc(nblock,ndir+nshr),
     2     tempOld(nblock),
     5     stressOld(nblock,ndir+nshr), stateOld(nblock,nstatev),
     6     enerInternOld(nblock), enerInelasOld(nblock),
     2     stressNew(nblock,ndir+nshr), stateNew(nblock,nstatev),
     3     enerInternNew(nblock), enerInelasNew(nblock)

* Corresponding .pyf
            integer :: nblock
            integer :: ndir
            integer :: nshr
            integer :: nstatev
            integer :: nprops
            real :: steptime
            real :: dt
            real dimension(nprops) :: props
            real dimension(nblock) :: density
            real dimension(nblock,ndir+nshr) :: straininc
            real dimension(nblock) :: tempold
            real dimension(nblock,ndir+nshr) :: stressold
            real dimension(nblock,nstatev) :: stateold
            real dimension(nblock) :: enerinternold
            real dimension(nblock) :: enerinelasold
            real dimension(nblock,ndir+nshr),intent(out) :: stressnew
            real dimension(nblock,nstatev),intent(out) :: statenew
            real dimension(nblock),intent(out) :: enerinternnew
            real dimension(nblock),intent(out) :: enerinelasnew

* Python source with call of Fortran routine:
    nblock = 1
    ndir = 3
    nshr = 3
    nstatev = 3
    nprops = 11
    stepTime = 1
    dt = 1
    props = np.array([10, 0.5, 1e10, 5, 1e12, 3e-6, 8e-6, 27, 2], float)
    density = np.array([[7.8e3]], float)
    strainInc = np.array([[1,-0.5,-0.5,0,0,0]], float)
    tempOld = np.array([[1]], float)
    stressOld = np.array([[1,1,1,1,1,1]], float)
    stateOld = np.array([[1,1,1]], float)
    enerInternOld = np.array([1], float)
    enerInelasOld = np.array([1], float)

    stressNew = np.array([[]], float)
    stateNew = np.array([[]], float)
    enerInternNew = np.array([[]], float)
    enerInelasNew = np.array([[]], float)

    stressNew, stateNew, enerInternNew, enerInelasNew = vumat(nblock, ndir, nshr, nstatev, nprops, stepTime, dt, props, density, strainInc, tempOld, stressOld, stateOld, enerInternOld, enerInelasOld)

When trying to run with Python 2.7 I get:
olof at ubuntu:~$ ./demo.py
unexpected array size: new_size=4, got array with arr_size=1
Traceback (most recent call last):
  File "./demo.py", line 33, in <module>
    main()
  File "./demo.py", line 30, in main
    stressNew, stateNew, enerInternNew, enerInelasNew = vumat(nblock, ndir, nshr, nstatev, nprops, stepTime, dt, props, density, strainInc, tempOld, stressOld, stateOld, enerInternOld, enerInelasOld)
VUMAT_Bergstrom_FCC.error: failed in converting 9th argument `stressold' of VUMAT_Bergstrom_FCC.vumat to C/Fortran array

Other stuff:
* python 2.7.6
* numpy/f2py 1.8.2
* gcc/gfortran 4.8.2
* ubuntu 14.04 LTS 32-bit

I have tried to google, read the f2py manual, fortran tutorials etc, but to no avail. I must also admit that my knowledge in python is so-so and fortran even less(!). What is the missing statement/syntax that I can’t get correct?

Your humble programmer, Olof


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