OpenEuphoria

RE: Uninitialized Variables

• Posted by Andy Serpa <renegade at earthling.net> Mar 24, 2002
• 554 views

jbrown1050 at yahoo.com wrote:
> On  0, Andy Serpa <renegade at earthling.net> wrote:
> > 
> > 
> > > I still don't understand what is wrong with
> equal(x,nan)
> > > 
> > > 
> > Simply, it doesn't work on my system.  If it works
> on yours, then that's 
> > a double-reason not to use it, as clearly it is
> unpredictable.  The 
> > other thread my have solved my problem, though --
> sprint(nan) returns 
> > "nan"!
> > 
> 

Turns out sprint() is way slow.  Here's my solution for now to detect 
inf's or nan's, which are effectively the same for my purposes:

constant inf = 1e300 * 1e300
constant nan = -(inf/inf)
constant inf_s = atom_to_float32(inf)
constant inf_neg_s = atom_to_float32(-inf)
constant nan_s = atom_to_float32(nan)
constant nan_neg_s = atom_to_float32(-nan)
constant bad_things = {inf_s, inf_neg_s, nan_s, nan_neg_s}

type nan_or_inf(atom x)
sequence x_seq
  x_seq = atom_to_float32(x)
  if find(x_seq, bad_things) then
    return 1
  else
    return 0
  end if
end type

Then, when I need to check, I just:

if nan_or_inf(x) then...