[petsc-dev] NaN constant?

[Lisandro Dalcin]

On 28 October 2015 at 19:29, Jed Brown <jed at jedbrown.org> wrote:
> Barry Smith <bsmith at mcs.anl.gov> writes:
>
>>   I don't want to be in the business of providing NaNs. They are nasty little beasts. PETSc should allow users to use NaN but should not enable them.
>
> FP non-normal values are also extremely slow on some architectures so
> it's a bad portability move to use them to identify missing values.  (Or
> maybe future hardware will embrace in-band missing values and make sure
> NaN is fast.)  In any case, signaling NaN is extremely useful for
> debugging.
>

I would also like to have PETSC_SNAN define for signaling NaN.


-- 
Lisandro Dalcin
============
Research Scientist
Computer, Electrical and Mathematical Sciences & Engineering (CEMSE)
Numerical Porous Media Center (NumPor)
King Abdullah University of Science and Technology (KAUST)
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