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Re: Floating Point computations in elisp
From: |
Christopher Dimech |
Subject: |
Re: Floating Point computations in elisp |
Date: |
Sun, 20 Dec 2020 04:43:25 +0100 |
> Sent: Sunday, December 20, 2020 at 6:15 AM
> From: "Emanuel Berg via Users list for the GNU Emacs text editor"
> <help-gnu-emacs@gnu.org>
> To: help-gnu-emacs@gnu.org
> Subject: Re: Floating Point computations in elisp
>
> Jean Louis wrote:
>
> > * Emanuel Berg via Users list for the GNU Emacs text editor
> > <help-gnu-emacs@gnu.org> [2020-12-18 20:09]:
> >
> >> (defun compute-space-distance (dist num-beams beam-width)
> >> (let*((spaces (1+ num-beams))
> >> (dist-covered (* num-beams beam-width))
> >> (dist-uncovered (- dist dist-covered))
> >> (space (/ dist-uncovered spaces 1.0) ))
> >> space ))
> >>
> >> ;; (insert (format "\n;; %.2f" (compute-space-distance 262 16 12)))
> >> ;; 4.12
> >
> > If I wish to arrive to Tau Ceti from Earth and it is maybe 11.8 light
> > years distant, how many years do I need to get there provided I trave
> > 5,000 km per hour?
>
> How about: 2 548 584 years
The ultimate question is then, how much will it cost. :)
> (defun tau-ceti (speed)
> (let*((dist (* 11.8 9.46 (expt 10 12)))
> (time (/ dist speed) )
> (days (/ time 24))
> (whole-days (round days)) )
> (format-seconds "%y years"
> (- (float-time (encode-time 0 0 0 whole-days 0 0))
> (float-time (encode-time 0 0 0 0 0 0)) ))))
> ;; (tau-ceti 5000)
>
> --
> underground experts united
> http://user.it.uu.se/~embe8573
> https://dataswamp.org/~incal
>
>
>
- Floating Point computations in elisp, Christopher Dimech, 2020/12/18
- Re: Floating Point computations in elisp, Michael Heerdegen, 2020/12/18
- Re: Floating Point computations in elisp, Emanuel Berg, 2020/12/18
- Re: Floating Point computations in elisp, Jean Louis, 2020/12/18
- Re: Floating Point computations in elisp, Emanuel Berg, 2020/12/19
- Re: Floating Point computations in elisp, Emanuel Berg, 2020/12/19
- Re: Floating Point computations in elisp, Emanuel Berg, 2020/12/19
- Re: Floating Point computations in elisp,
Christopher Dimech <=
- Re: Floating Point computations in elisp, Stefan Monnier, 2020/12/19
- Re: Floating Point computations in elisp, Christopher Dimech, 2020/12/19