[SciPy-user] how to make a sinc(x) function - "divide by zero" !
haase at msg.ucsf.edu
Mon Dec 12 12:26:34 CST 2005
that's the answer I hoped for ;-)
I was using something like CVS numarray - around 1.3 ;
(na.array has not dtype argument yet...)
but now it works !!?? (Maybe the errorMode stack got messed up when I was
playing with it !)
On Monday 12 December 2005 10:13, Perry Greenfield wrote:
> On Dec 12, 2005, at 12:32 PM, Sebastian Haase wrote:
> > Hi,
> > I was trying to implement a "sinc" [sin(x)/x] in numarray. But the
> > "where"-semantics makes it choke on the x=0: 0/0 case.
> > (This should of course work for x being an array - so "if" is no
> > option)
> > The best I could come up with was:
> > def sinc(r):
> > na.Error.pushMode(all="ignore")
> > a = na.where(r, na.divide(na.sin(r),r), 1)
> > na.Error.popMode()
> > return a
> > but I still seem to get a warning...
> >>>> F.sinc(0)
> > Warning: Encountered invalid numeric result(s) in divide
> > 1.0
> > What is a better way of doing this ?
> > Thanks,
> > Sebastian Haase
> That's odd. When I try your example it prints 1 without any warning.
> What version and platform are you running on?
> Thanks, Perry
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