# 0-extent matrices?

**Kurt Hornik
**
Kurt.Hornik@ci.tuwien.ac.at

*Sun, 12 Apr 1998 16:57:34 +0200 (CEST)*

>>>>>* Thomas Lumley writes:
*
>* Implementing 0-extent matrices turns out to be easy -- it's almost
*>* entirely a matter of removing the tests for 0. There seems to be only one
*>* thing that may require special-case handling, but I'm not sure what the
*>* Right Thing to do is.
*
>* If m is a 0x4 matrix, say, what should 2*m, 2+m and so on return?
*
>* Since m+m is a 0x4 matrix but 2*as.vector(m) is NA we can't have complete
*>* consistency. My preference is for these operations to happen elementwise
*>* -- ie m+m is a 0x4 matrix. Comments?
*
Sounds very much like going the Octave/MATLAB way. I thought we'd
eventually have a `Matrix' class for such things?
-k
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