numpy.f2py produces wrong results for arrays of strings #4519
Description
I have tried several variants with arrays of fortran-character strings and none of them did work (fixed/variable string length and array dimension).
I even tried to use iso_c_binding with 2-dimensional character(kind=C_CHAR) array, but this seemed to produces strided strings (row-/column-major reordering of the data).
I could not really find anything helpful related to this problem. In http://cens.ioc.ee/projects/f2py2e/README.html there's a remark from 2004 that this should work.
So here a simple example:
module CharArrayTest
implicit none
contains
subroutine charArrayIn(myStrList)
character(len=*), intent(in) :: myStrList(:)
integer :: i
write(*,*) 'Called "charArrayIn" with args:'
do i = 1, size(myStrList), 1
write(*,*) i, trim(myStrList(i))
end do
end subroutine charArrayIn
end module CharArrayTest
Obviously calling this function from Fortran works fine.
I can compile it using
f2p -m Fortran -c chararraytest.f90
But with my small test program I obtain strange results:
from Fortran import chararraytest
test_data = ( '',
'text',
[('1',), ('2',), ('3',)],
['',''] )
print chararraytest.chararrayin.__doc__
for test_str in test_data:
print 'calling chararrayin with args:', repr(test_str)
chararraytest.chararrayin(test_str)
I get the following output:
chararrayin - Function signature:
chararrayin(mystrlist)
Required arguments:
mystrlist : input rank-1 array('S') with bounds (f2py_mystrlist_d0)
calling chararrayin with args: ''
Called "charArrayIn" with args:
calling chararrayin with args: 'text'
Called "charArrayIn" with args:
1 text
2 �
3 xV#T
4 �
calling chararrayin with args: (('1',), ('2',), ('3',))
Called "charArrayIn" with args:
1 123
2
3
calling chararrayin with args: ('', '')
unexpected array size: size=2, arr_size=0, rank=1, effrank=1, arr.nd=2, dims=[ 2 ], arr.dims=[ 2 0 ]
Traceback (most recent call last):
File "test.py", line 12, in <module>
chararraytest.chararrayin(test_str)
Fortran.error: failed in converting 1st argument `mystrlist' of Fortran.chararraytest.chararrayin to C/Fortran array
When I use fixed character length strings, e.g. character(len=20), the results look similar.
System:
Debian testing, 64 bit
uname -rvmo
3.13-1-amd64 #1 SMP Debian 3.13.5-1 (2014-03-04) x86_64 GNU/Linux
Python 2.7.6
NumPy 1.7.1
dpkg --list python-numpy
[...]
python-numpy 1.7.1-5 amd64
I also tried an installation of numpy 1.8 on another 64 bit Linux machine.