Re: [Toon-members] comparing vectors of different sizes

[E. Rosten]

On Tue, 16 Nov 2010, Alex Flint wrote:

> Hi there,
> It seems that TooN crashes when comparing two vectors of different sizes, at least one of 
> which is dynamic. The error is "size mismatch",
> which is understandable, though in this case (checking for equality) it would 
> seem to make more sense to return false. What do you think?

The current design of TooN is that everything that is a compile time error 
using static sized vectors should crash with dynamic vectors. I.e. it 
indicates that the program is not correct and therefore no recovery cannot 
be performed.

However that makes the assumption that there is no reasonable case where 
one might want to compare two vectors of different lengths. Actually, even 
the test current for equality is a bit dubious since one will usually be 
at the mercy of floating point numbers and rounding errors.

Would you mind describing why you are comparing vectors of different 
lengths for equality? I'd like to better understand the use cases of TooN 
which I haven't considered.


> Also, in the more general case of unavoidable size mismatches, I would 
> like to have TooN throw exceptions. This seems to have been implemented 
> via TOON_TEST_INTERNALS but I'm not sure what other ramifications this 
> debug flag will cause -- any suggestions?

I expect you don't want to run with that flag on. It will make your 
program slow, also it's not part of the public interface, so it may change 
without warning.

-Ed

--
Edward Rosten                     Machine Intelligence Laboratory
http://mi.eng.cam.ac.uk/~er258          Department of Engineering
+44 1223 7 65960                          University of Cambridge