[Numpy-discussion] ANN: numarray-1.4.1

Travis Oliphant oliphant at ee.byu.edu
Fri Oct 28 12:29:43 EDT 2005

Todd Miller wrote:

> Francesc Altet wrote:
>> Hi Todd,
>> I've just installed numarray 1.4.1 and pass my tests over it.
>> Everything goes well, except some small detail:
>> Python 2.4.2 (#2, Sep 29 2005, 00:23:59)
>> [GCC 4.0.2 (Debian 4.0.1-9)] on linux2
>> Type "help", "copyright", "credits" or "license" for more information.
>>>>> import Numeric
>>>>> import numarray
>>>>> Numeric.__version__
>> '24.0b2'
>>>>> numarray.__version__
>> '1.4.1'
>>>>> na=numarray.array([ 51.], type=numarray.Float64)
>>>>> Numeric.array(na, typecode='d')
>> Traceback (most recent call last):
>>  File "<stdin>", line 1, in ?
>> TypeError: expected a writeable buffer object

> This looks like a coordinated change in both numarray and Numeric.   
> (Travis?)  I updated to Numeric-24.0 and all was well.

> It appears the __array_data__ protocol improved to know about 
> readonly-ness.  In order to support the readonly behavior in 
> numarray,  I think the change must be made in lockstep.  We could 
> however back out support for readonly while Numeric-24.0 becomes more 
> pervasive.

Yes, basically the __array_data__ protocol was essentially pointless 
before because it just returned a buffer object which

1) did nothing more than the object itself supporting the buffer 
protocol and
2) could not handle strided (discontiguous) arrays.

The new array protocol handles the situation much better and allows 
discontiguous arrays to be shared.

However, it does create some backward compatibility issues.  But, 
because Numeric 24.0b2 was a *beta* release I don't see this as a real 
problem.   Get the final release of Numeric, which will handle the array 
protocol correctly (note it will also handle the old __array_data__ 
format as well).

Todd,  I was not sure how to change numarray so it would consume the new 
protocol correctly.   So, I'm not sure how numarray interprets the 
__array_data__ attribute.


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