How to represent the infinite ?
Cliff Wells
logiplexsoftware at earthlink.net
Thu Jun 20 19:47:15 CEST 2002
On Thu, 20 Jun 2002 17:02:33 +0200
erreur wrote:
> Will somebody have an idea, to represent the infinite one?
>
> I have variables to initialize with is +inf (or - inf). To be sure that
> later, all will be smaller (or larger) than my variables.
> I tried to redefine the operators on an object. It goes for Inf>10 but I do
> not arrive for 10>Inf (because that takes > of Int).
>
> --------------------
>
> def __gt__(self, val):
>
> return 1
>
> --------------------
Well, here's a start:
class inf(int):
def __init__(self):
int.__init__(self)
self.sign = 1
def __str__(self):
return "<infinity>"
def __repr__(self):
return "<infinity>"
def __cmp__(self, n):
if isinstance(n, inf):
return cmp(self.sign, n.sign)
return self.sign
def __neg__(self):
retval = inf()
retval.sign = self.sign * -1
return retval
if __name__ == '__main__':
import sys
m = -inf()
n = inf()
assert(m < n)
assert(n > m)
assert(m == m)
assert(n == n)
assert(m != n)
assert(m < 0)
assert(n > 0)
assert(m < -sys.maxint)
assert(n > sys.maxint)
assert(m < -m)
assert(n == -m)
--
Cliff Wells, Software Engineer
Logiplex Corporation (www.logiplex.net)
(503) 978-6726 x308 (800) 735-0555 x308
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