Thanks Paul.

I suppose this is now going slightly out of bounds for f2py.   What I am looking for is the fortran kind type for a byte.  I thought that this was int8.  I guess the question is how to identify the kind type.  Although I have verified that integer(1) seems to work for me, I would really like to know why and your answer alludes to that.

Please excuse my ignorance on this topic.  Can you perhaps educate me a little on 'literal kind values'?  I take you to mean that
'int8' is not a literal kind value while 1 and 8 are examples of literal kind values.

Thanks,
John



On Tue, Apr 17, 2012 at 10:12 AM, Paul Anton Letnes <paul.anton.letnes@gmail.com> wrote:
Ah, come to think of it, I think that f2py only supports literal kind values. Maybe that's your problem.

Paul

On 17. apr. 2012, at 07:58, Sameer Grover wrote:

> On Tuesday 17 April 2012 11:02 AM, John Mitchell wrote:
>> Hi,
>>
>> I am using f2py to pass a numpy array of type numpy.int8 to fortran.  It seems like I am misunderstanding something because I just can't make it work.
>>
>> Here is what I am doing.
>>
>> PYTHON
>> b=numpy.array(numpy.zeros(shape=(10,),dtype=numpy.int8),order='F')
>> b[0]=1
>> b[2]=1
>> b[3]=1
>> b
>> array([1, 0, 1, 1, 0, 0, 0, 0, 0, 0], dtype=int8)
>>
>>
>>
>> FORTRAN
>> subroutine print_bit_array(bits,n)
>>    use iso_fortran_env
>>    integer,intent(in)::n
>>    integer(kind=int8),intent(in),dimension(n)::bits
>>    print*,'bits = ',bits
>> end subroutine print_bit_array
>>
>>
>> RESULT when calling fortran from python
>> bits =     1    0    0    0    0    0    0    0    1    0
>>
>> Any Ideas?
>> thanks,
>> John
>>
>>
>>
>>
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>>
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> It seems to work if "integer(kind=int8)" is replaced with "integer(8)" or "integer(1)".  Don't know why, though.
>
> Sameer
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