[Tutor] help using f2py

[Jose Amoreira]

Hello!
I posted this question on the f2py list but since I haven't got any answers 
(yet), I thought I'd try my luck here.

I'm having a hard time wrapping a fortran subroutine into a python module. The 
problem seems to be related to having a subroutine argument to the fortran 
subroutine.
A simple version of my problem is the following. Consider a subroutine (sub), 
which takes as argument a real  array (x), the dimension (n) of that array and 
another subroutine (other_sub) that is to be called by sub :

file sub.f95
----------------------------------------------
subroutine sub(x,other_sub,n)
integer::n
real, dimension(n)::x
external other_sub
call other_sub(x)
end subroutine sub
----------------------------------------------
The gnu fortran compiler compiles this snippet without any warnings or errors. 
However, when I run it through f2py, all I get is a bunch of errors (see below 
the error output). I'm not sure if this has any relevance but if I change 
argument x to a real scalar (instead of an array), then f2py executes fine and 
the python module is generated.
I just don't get it! Can anybody explain me what I am doing wrong, please? 
Thanks in advance.
Jose Amoreira


Part of the output of f2py -m sub -c sub.f95:
----------------------------------------------
creating /tmp/tmpyHp76U/tmp
creating /tmp/tmpyHp76U/tmp/tmpyHp76U
creating /tmp/tmpyHp76U/tmp/tmpyHp76U/src.linux-x86_64-2.6
compile options: '-I/tmp/tmpyHp76U/src.linux-x86_64-2.6 -
I/usr/lib64/python2.6/site-packages/numpy/core/include -
I/usr/include/python2.6 -c'
gcc: /tmp/tmpyHp76U/src.linux-x86_64-2.6/fortranobject.c
gcc: /tmp/tmpyHp76U/src.linux-x86_64-2.6/submodule.c
/tmp/tmpyHp76U/src.linux-x86_64-2.6/submodule.c: In function 
‘cb_other_sub_in_sub__user__routines’:
/tmp/tmpyHp76U/src.linux-x86_64-2.6/submodule.c:306: error: ‘n’ undeclared 
(first use in this function)
/tmp/tmpyHp76U/src.linux-x86_64-2.6/submodule.c:306: error: (Each undeclared 
identifier is reported only once
/tmp/tmpyHp76U/src.linux-x86_64-2.6/submodule.c:306: error: for each function 
it appears in.)
/tmp/tmpyHp76U/src.linux-x86_64-2.6/submodule.c: In function 
‘cb_other_sub_in_sub__user__routines’:
/tmp/tmpyHp76U/src.linux-x86_64-2.6/submodule.c:306: error: ‘n’ undeclared 
(first use in this function)
/tmp/tmpyHp76U/src.linux-x86_64-2.6/submodule.c:306: error: (Each undeclared 
identifier is reported only once
/tmp/tmpyHp76U/src.linux-x86_64-2.6/submodule.c:306: error: for each function 
it appears in.)
error: Command "gcc -pthread -fno-strict-aliasing -DNDEBUG -fmessage-length=0 
-O2 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector -funwind-tables -
fasynchronous-unwind-tables -g -fwrapv -fPIC -I/tmp/tmpyHp76U/src.linux-
x86_64-2.6 -I/usr/lib64/python2.6/site-packages/numpy/core/include -
I/usr/include/python2.6 -c /tmp/tmpyHp76U/src.linux-x86_64-2.6/submodule.c -o 
/tmp/tmpyHp76U/tmp/tmpyHp76U/src.linux-x86_64-2.6/submodule.o" failed with 
exit status 1
-------------------------------------