[Cuis-dev] Negative sqrt

Juan Vuletich juan at jvuletich.org
Mon Jan 4 11:04:03 PST 2021

Hi Werner,

No one ever considered removing support for NaNs! They are useful in 
many kind of algorithms, not just genetic, and are required by the IEEE 

The discussion was whether it is needed to add support for Signaling 
NaNs, that we never had (and I believe are not needed at all).


On 1/4/2021 2:31 PM, werner kassens via Cuis-dev wrote:
> Hi Juan,
> a numerical computation resulting in a NaN instead of an error can
> simplify coding of genetic algos or genetic programming dealing with
> numeric problems. iow i would prefer if this behaviour would not disappear.
> werner
> On 12/30/20 4:57 PM, Juan Vuletich via Cuis-dev wrote:
>> .....
>> Having worked with numerical algorithms using floating point, mainly
>> in image and signal processing, but also in numerical linear algebra
>> and discrete simulations, I never saw Signaling NaNs have any
>> relevance. I don't think they are used much in practice. And they can
>> be implemented in Smalltalk.
>> Still, you may bring the issue to VM-Dev. If floating point primitives
>> are made to fail when encountering a Signaling NaN, I'll be happy to
>> raise an appropriate Smalltalk exception.
>> Thanks,

Juan Vuletich

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