On 28 October 2015 at 19:29, Jed Brown <[email protected]> wrote: > Barry Smith <[email protected]> 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) http://numpor.kaust.edu.sa/ 4700 King Abdullah University of Science and Technology al-Khawarizmi Bldg (Bldg 1), Office # 4332 Thuwal 23955-6900, Kingdom of Saudi Arabia http://www.kaust.edu.sa Office Phone: +966 12 808-0459
