On Jan 10, 2017, at 16:46 , Raymond Toy <toy.raymond@gmail.com> wrote: ...
Marco> Well. I have been fooling around (read: veered off a Marco> tangent) with interval arithmetic, where it looks like you Marco> need to ensure that your rounding modes are set to positive Marco> or negative infinity when using an end points Marco> representation. That’s were it all started.
That's one way. I vaguely recall some Fortran TOMS package that included interval arithmetic, but I think it just did something simple like multiply by 1+e for some tiny e.
Setting the rounding modes twice (up and down) for every operation is pretty expensive.
Ok. I presume that the references talk of rounding modes only because they assume some “very-close-to-the-metal” implementation. In any case, the need for NaNs and infinities is there. And right now CL is lacking in this respect. Cheers -- Marco Antoniotti