unofficial mirror of help-gnu-emacs@gnu.org
 help / color / mirror / Atom feed
From: Emanuel Berg via Users list for the GNU Emacs text editor <help-gnu-emacs@gnu.org>
To: help-gnu-emacs@gnu.org
Subject: lights.el, compute illumination [EMACS CLIMATE ACTION INITIATIVE]
Date: Wed, 13 Jan 2021 13:47:28 +0100	[thread overview]
Message-ID: <87v9c1rokf.fsf@zoho.eu> (raw)

;;; -*- lexical-binding: t -*-
;;;
;;; this file:
;;;   http://user.it.uu.se/~embe8573/emacs-init/lights.el
;;;   https://dataswamp.org/~incal/emacs-init/lights.el
;;;
;;; data:
;;;   https://dataswamp.org/~incal/data/LIGHTS

(defun illumination-score (w lm)
  (interactive "nW: \nnlm: ")
  (let*((le (/ lm w 1.0))
        (max   75) ; LED luminous efficacy (lm/W)
        (min   15) ; incandescent ditto
        (scale (- max min))
        (score (* 100 (/ (- le min) scale)) ))
    (format "%.0f%%" score) ))

(when nil
  (illumination-score
   (+ (* 2 1) (* 2 2.8) 8 7) ; 22.6 W
   (+ (* 2 120) 500 525)     ; 1265 lm
   )                         ; 68%
)

Turns out (as you see) that my conapt, with 4 or 6 bulbs,
scores 68%!

-- 
underground experts united
http://user.it.uu.se/~embe8573
https://dataswamp.org/~incal




                 reply	other threads:[~2021-01-13 12:47 UTC|newest]

Thread overview: [no followups] expand[flat|nested]  mbox.gz  Atom feed

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

  List information: https://www.gnu.org/software/emacs/

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=87v9c1rokf.fsf@zoho.eu \
    --to=help-gnu-emacs@gnu.org \
    --cc=moasenwood@zoho.eu \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).