rotheta=:[: +. ([: r. [) * [: +.^:_1 ]
1r2p1 rotheta 3 4
_4 3
1r4p1 rotheta 2 2$ 3 4 _1 1
_0.707107 4.94975
_1.41421 0
2 1$ 1r2p1 1r4p1 rotheta 2 2$ 3 4 _1 1
_4 3
_1.41421 0
It would be simpler to enter positions as complex numbers in the first
place.
(r.1r2p1) * 3j4
_4j3
Don Kelly
On 2/16/2016 8:50 PM, Kip Murray wrote:
I'm retired with time to "fool around". Finding an old rot90 verb that
used multiplication by a 2 by 2 matrix, I sought a more direct way using
complex numbers and found one of the solutions that was posted. I also
learned a lot from the other solutions posted, thanks everyone!
New puzzle: find a complex analysis way to do a rotation given its angle in
radians, examples:
1r2p1 rottheta 3 4
_4 3
1r4p1 rottheta _1 1
_1.414213562 0
--Kip
I'm also a former math professor!
On Tuesday, February 16, 2016, David Lambert <[email protected]> wrote:
what's your agenda, are you writing a book? Isn't there a homogeneous
coordinate system/transformation lab?
On 02/16/2016 06:16 PM, [email protected] wrote:
Date: Tue, 16 Feb 2016 15:18:43 -0600
From: Kip Murray<[email protected]>
To:"[email protected]" <[email protected]>
Subject: [Jprogramming] A plane rotation
Message-ID:
<caofworgvydb1nmjwxkb0wosyfnlubxcdz20sv11uksfcfay...@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8
Fairly easy: write a verb that rotates a point in the plane by the angle
of
a given complex number. For example
1j1 rot 1 1 NB. Rotate 1 1 counterclockwise 45 degrees
0 1.414213562
Background information: when you multiply two complex numbers the
magnitudes are multiplied and the angles are added.
--Kip Murray
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