[Gridflow-dev] cv.Div, cv.Mul + errors

Mathieu Bouchard matju at artengine.ca
Thu Oct 25 14:50:51 EDT 2007

On Wed, 24 Oct 2007, Alexandre Castonguay wrote:

> Thanks for the fix : [cv.Div] and [cv.Mul] work now.  I tried comparing 
> the results of [cv.Div] with [# div] and [# /] and their results are not 
> exactly the same as they both round down and [cv.Div] rounds up.

[# /] rounds towards zero, which is up for negative values.

[# div] is the one that always rounds downwards. (I said it the other way 
around yesterday). Also, [# >>] always rounds downwards too.

[cv.Div] adds half of the divisor and rounds downwards. Overall, it rounds 
to the nearest, up or down.

For floats there is essentially no difference, as there is no integer 

> Also, once an error has been triggered by sending a grid of different 
> dimensions, GridFlow seems unable to recover.

It seems that the error handler doesn't work properly. I will replacing 
RAISE() by a post() later. However, the error messages provided by CV are 
not adequate, so instead I will prevent CV errors by preemptively raising 
GF errors instead, and then the error handler issue is moot.

> Re-creating the object that triggered the error or closing the patch 
> doesn't help.

Yow. That's quite hardcore. I don't know how this can be, but I have to 
assume that it is because RAISE() is not compatible with CV error handlers 
at all.

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| Mathieu Bouchard - tél:+1.514.383.3801, Montréal QC Canada

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