[Numpy-discussion] Re: Trying out Numeric3

Michiel Jan Laurens de Hoon mdehoon at ims.u-tokyo.ac.jp
Tue Mar 22 17:08:01 EST 2005

Travis Oliphant wrote:
> Michiel Jan Laurens de Hoon wrote:
>> Travis Oliphant wrote:
>>> Michiel Jan Laurens de Hoon wrote:
>>>> Another warning was that PyArrayObject's "dimensions" doesn't seem 
>>>> to be an int array any more.
>>> Yes.   To allow for dimensions that are bigger than 32-bits, 
>>> dimensions and strides are (intp *).  intp is a signed integer with 
>>> sizeof(intp) == sizeof(void *).  On 32-bit systems, the warning will 
>>> not cause problems.  We could worry about fixing it by typedefing 
>>> intp to int (instead of the current long for 32-bit systems).
>> Do 4 gigabyte 1D numerical python arrays occur in practice? If I 
>> understand correctly, the current implementation gives dimensions a 
>> different pointer type on different platforms. This will break 
>> extension modules on platforms other than 32-bits, as the extension 
>> module expects dimensions to be a pointer to int.
> This is a must have.   Yes, extension modules will have to be recompiled 
> and pointers changed on 64-bit platforms,  but this has to be done.      

Why? There needs to be a good reason to break compatibility. Who needs this?


Michiel de Hoon, Assistant Professor
University of Tokyo, Institute of Medical Science
Human Genome Center
4-6-1 Shirokane-dai, Minato-ku
Tokyo 108-8639

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