The "embarassing" example happens because the full scope of "two's
complement" notation implies fixed-width binary numbers, not the
variable-width version given in this thread.
On Wed, Dec 14, 2011 at 10:41 AM, Kip Murray <k...@math.uh.edu> wrote:
> On 12/14/2011 6:07 AM, Linda Alvord wrote:
> > I really don't think that you can ever write a program good enough that
> the
> > the number 8 in binary is _8 in decimals
> >
> > hcinv 1 0 0 0
> > _8
>
> THAT /IS/ EMBARRASSING !
>
> > I have lived my mathematical life without being able to write negative
> > binary numbers. I have always ignored two's complements as beyond my
> scope
> > of interest. It is like saying there are no negative numbers. It will
> be
> > ok if 13 stands for _13 and we'll all be happy.
> >
> > I'm sure that much of the world deals well without imaginary numbers.
> > However, they must have been a mess to develop so they work flawlessly.
> > Note that they do have a strange appearance but if you understand them
> you
> > get used to them.
> >
> > In my world, if I want _8 I write _1 0 0 0 which is in the 8 4 2
> 1
> > 8's digit. So what is _14 ?
> >
> > Linda
>
> IN YOUR WORLD _14 IS
>
> - 1 1 1 0
> _1 _1 _1 0
>
> AND IN TWO'S-COMPLEMENT IT IS
>
> tcng 0 1 1 1 0
> 1 0 0 1 0
>
> ------------------
>
> stack =: ,.&.|: NB. stack x over y
>
> hv =: (0 {:: <"1) :: ] NB. return head vector
>
> Tbln =: 2 2 2 $ 0 0,1 1,1 1,0 1 NB. table for tcng, see opn
>
> ban =: 0 ,~ 0 ,.~ 0 ,.~ ] NB. build argument, see tcng
>
> opn =: ] stack~ (0 { [) , Tbln {~ [: < (0 { [) ,~ 2 { [: hv ]
>
> tcng =: (1 {"1 [: }: [: opn/ ban)"1 NB. TWO'S-COMPLEMENT NEGATIVE
>
> ----------------------------------------------------------------------
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>
--
Devon McCormick, CFA
^me^ at acm.
org is my
preferred e-mail
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