[Numpy-discussion] can't resize ndarray subclass

Tim Hochberg tim.hochberg at cox.net
Tue Feb 28 14:06:09 EST 2006

Travis Oliphant wrote:

> Zachary Pincus wrote:
>> However a new problem has me nearly tearing my hair out. Calling the  
>> resize method on an instance of such a subclass works fine. However,  
>> calling a method that calls 'self.resize' breaks! And worse, it  
>> breaks in such a way that then subsequent calls to resize also break.
> In SVN version of numpy, there is a new keyword argument to resize 
> (refcheck).  If this keyword argument is 0 (it defaults to 1), the 
> reference-count check is not performed.  Thus, if you are sure that 
> your array has not exposed it's memory to another object, then you can 
> set refcheck=0 and the resize will proceed.

I'd suggest that this get exposed as a separate function, for instance 
A._unchecked_resize(size). It seems much less likely that this will 
accidentally get called than that somone will mistakenly throw a second 
boolean argument into resize.


> If you really did expose your memory to another object, this could 
> lead to segfaults in exactly the same way that exposing the memory to 
> a Python array (array module) and then later resizing (which Python 
> currently allows) would cause problems.
> Be careful...
> -Travis
> -------------------------------------------------------
> This SF.Net email is sponsored by xPML, a groundbreaking scripting 
> language
> that extends applications into web and mobile media. Attend the live 
> webcast
> and join the prime developer group breaking into this new coding 
> territory!
> http://sel.as-us.falkag.net/sel?cmd=lnk&kid=110944&bid=241720&dat=121642
> _______________________________________________
> Numpy-discussion mailing list
> Numpy-discussion at lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/numpy-discussion

More information about the NumPy-Discussion mailing list