[SciPy-user] numpy array in ctype struct

Travis E. Oliphant oliphant@enthought....
Tue Jan 15 17:01:25 CST 2008


Thomas Heller wrote:
> Travis E. Oliphant schrieb:
>   
>> Thomas Heller wrote:
>>     
>>> Travis E. Oliphant schrieb:
>>>   
>>>       
>>>>    You can create an array from a pointer to memory and a 
>>>> description of the data that is much like the ctypes structure.   At 
>>>> some point, there should be a direct conversion from ctypes objects to 
>>>> NumPy data-types, but nobody has written that yet.
>>>>     
>>>>         
>>> Is there anything that should be added to ctypes (Python 2.6 isn't too
>>> far away) that would help with this conversion?
>>>   
>>>       
>> One approach would for ctypes objects to describe their data-type using 
>> the new additions to the struct syntax (i.e. fully support the new 
>> buffer interface including data-type description as defined in PEP 
>> 3118).   This should be going in Python 2.6 as well (but I need help in 
>> the implementation). 
>>
>> Then, NumPy arrays will support consuming the syntax as well and it 
>> should be an easy thing to pass back and forth between NumPy array views 
>> and ctypes-objects views of memory.   I think such a thing would be very 
>> powerful.
>>
>>     
>
> I assume the implementation would have to take place in the py3k branch,
> and later it would (hopefully) be ported to the trunk?
>
> Do I understand correctly that __array_interface__ and __array_struct__
> are superseeded by what's in PEP 3118, or are these only out of scope for the PEP?
>
>   
They are superseded.   We will have them for a while in the NumPy world, 
but PEP 3118 is the right concept going forward as it is in the Python 
Type Object.


-Travis




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