Message-ID: <loom.20100118T050318-545@post.gmane.org>
Date: 2010-01-18T04:05:52Z
From: Ben Bolker
Subject: function to set log(0)=0 not working on tables or vectors
David Winsemius <dwinsemius <at> comcast.net> writes:
>
>
> On Jan 17, 2010, at 8:17 PM, maiya wrote:
>
> >
> > There must be a very basic thing I am not getting...
> >
> > I'm working with some entropy functions and the convention is to use
> > log(0)=0.
> >
>
> I suppose the outcome of that effort may depend on whether you have
> assumed the needed godlike capacities to change the laws of
> mathematics. But I suppose that as the Earth mother that might occur
> to you. Go ahead, define a new mathematics.
My guess is that the real intention here is
to define 0*log(0) = 0 rather than log(0) = 0 --
really the assertion is that lim(x -> 0) x log(x) = 0,
which must be true for some reasonable limiting conditions.