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MyASPN >> Mail Archive >> numpy-discussion
numpy-discussion
Re[2]: [Numpy-discussion] missing array type
by Alan G Isaac other posts by this author
Feb 27 2006 3:43PM messages near this date
Re: [Numpy-discussion] missing array type | [Numpy-discussion] bug report: nonzero on masked arrays
On Mon, 27 Feb 2006, Sasha apparently wrote: 
>  If you agree that zero-stride array would provide the 
>  functionality that you need, it may tip the ballance 
>  towards accepting that patch. 

I am out of my technical depth here.  Based on your 
examples, zero-stride arrays seem both logical and 
desirable.  They do seem just right for a simpler (and 
substantially generalized) nd_grid.  But I think they only 
partially address problems two other that have come up.

1. repmat
   http://www.mathworks.com/access/helpdesk/help/techdoc/ref/repmat.html#998661

Perhaps you will say that the best representation of 
a repmat will use 4 dimensions, two with zero strides?
I wonder if a more general cycling is needed for a natural 
repeated matrix.

2. Kronecker product:
   http://www.mathworks.com/access/helpdesk/help/techdoc/ref/kron.html#998881
   This seems a different issue altogether.  I suspect the 
   right way to produce kron(x,y) is usually as a class 
   whose data is x and y, with the Kronecker product never 
   actually stored in memory.  I do not see zero-stride 
   arrays as helping here.

Cheers,
Alan Isaac




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Alan G Isaac
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Tim Hochberg
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Travis Oliphant
Christopher Barker
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Alan G Isaac

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