Re: [pure-lang-users] math.pure

[John C. <co...@cc...>]

Eddie Rucker scripsit:
> Should we have the following rules?
> _+:nan = nan;
> nan+:_ = nan;
> nan<:_ = nan;
> _<:nan = nan;
> 
> My thinking is that if any part of a complex number is nan then the
> whole thing is not a number. OTOH, inf+:inf, 0+:inf, inf+:0, etc, you
> might want to keep that way for either further processing or to let the
> user know the result is a complex number. What does everyone think about
> this?

I'd avoid this: it's easy enough to add a post-processing ruleset
to make the change.  Just because the real side of a computation has
lost significance doesn't mean the imaginary side doesn't still contain
useful data (or vice versa).  The whole point of inf and nan is to allow
computation to continue, postponing the check for significance to the end.

-- 
John Cowan     http://ccil.org/~cowan    co...@cc...
Monday we watch-a Firefly's house, but he no come out.  He wasn't home.
Tuesday we go to the ball game, but he fool us.  He no show up.  Wednesday he
go to the ball game, and we fool him.  We no show up.  Thursday was a
double-header.  Nobody show up.  Friday it rained all day.  There was no ball
game, so we stayed home and we listened to it on-a the radio.  --Chicolini