define

[Bengt Richter]

On Mon, 12 May 2003 11:00:48 -0500, Jeff Epler <jepler at unpythonic.net> wrote:

>On Mon, May 12, 2003 at 09:21:30AM -0600, Daniel Fackrell wrote:
>> "Bengt Richter" <bokr at oz.net> wrote in message
>> news:b9j286$74l$0 at 216.39.172.122...
>> > Ok, let's do the whole deal ;-)
>> >
>> >     b = self.b
>> >     sign = self.sign
>> >     a = self.a
>> >     c = self.c
>> >     y = (-b + sign*sqrt(b**2 - 4.0*a*c))/2.0*a
>> >     self.y = y
>> > vs
>> >     with self ~ sqrt:
>> >         y = (-b + sign*sqrt(b**2 - 4.0*a*c))/2.0*a
>> 
>> 
>> I would probably write the former as:
>> 
>> (a, b, c, sign) = (self.a, self.b, self.c, self.sign)
>> self.y = (-b + sign*sqrt(b**2 - 4.0*a*c))/2.0*a
>
>I can't help but notice that when you wrote
>> >         y = (-b + sign*sqrt(b**2 - 4.0*a*c))/2.0*a
>you were wrong.  The correct code is
>|           y = (-b + sign*sqrt(b**2 - 4.0*a*c))/(2.0*a)
>because a/b*c == (a/b)*c, not a/(b*c).
>
>I'm not sure how far back in the thread this error goes, but it's some
>kind of argument against overly complex expressions <sqrt(3)/2 wink>
>
Dang, that's embarassing. Good catch. The error goes back to the beginning ;-/

Regards,
Bengt Richter