Alan G Isaac wrote:
On Thu, 25 May 2006, Robert Kern apparently wrote:
That your demonstration results in the desired exact 0.0 for multiples of 2*pi is an accident. The results for values other than integer multiples of pi will be as wrong or more wrong.
It seems that a continuity argument should undermine that as a general claim. Right?
What continuity? This is floating-point arithmetic. [~]$ bc -l bc 1.06 Copyright 1991-1994, 1997, 1998, 2000 Free Software Foundation, Inc. This is free software with ABSOLUTELY NO WARRANTY. For details type `warranty'. scale = 50 s(1000000) -.34999350217129295211765248678077146906140660532871 [~]$ python Python 2.4.1 (#2, Mar 31 2005, 00:05:10) [GCC 3.3 20030304 (Apple Computer, Inc. build 1666)] on darwin Type "help", "copyright", "credits" or "license" for more information.
from numpy import * sin(1000000.0) -0.34999350217129299 sin(1000000.0 % (2*pi)) -0.34999350213477698
But like I said: I was just wondering if there was anything exploitable here.
Like I said: not really. -- Robert Kern "I have come to believe that the whole world is an enigma, a harmless enigma that is made terrible by our own mad attempt to interpret it as though it had an underlying truth." -- Umberto Eco