My slide rule had a half-scale scale, so you could just read off squares and square roots. This elliptic-curve-calculator is a clever nomogram. My freshman seminar at MIT was a course in nomography taught by Douglas P Adams. It's amazing how clever nomographers could be, but of course now that just about everyone carries around an electronic computation device, it is a lost art. It did, however, inspire me some years later to write a pile of PostScript to (amongst other things) plot nomograms: https://dl.dropbox.com/u/17718830/plot.ps I suppose writing PostScript has also become a lost art. On 2012-08-30 04:28, Phil Carmody wrote:
From: "Adam P. Goucher"
http://cp4space.wordpress.com/2012/08/29/elliptic-curve-calculator/ Warren wrote: "Why is this better than a slide rule?" It can compute square roots, If you're printing out your slide rule, square root calculation is just folding the slide rule in 2, or other disection.
is much cheaper, Not if you're also printing your slide rule out on paper. (My first slide rule was hand-made from paper stuck to card, made after seeing my dad's old school slide rule from the days before anything electronic.)
and doesn't require any moving parts. Not so, there's the straight edge that you have to manipulate.
It's more of a demonstration of the interchangeability of elliptic curves and modular arithmetic, not a suggestion that this be used for practical purposes. And indeed for that it was most interesting, as I too had not encountered Guy's original formulation before.
Phil
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