Re: Regarding multiply-armed equiangular (or Logarithmic) spirals

[Juan Pablo Carbajal]

On Mon, Sep 17, 2012 at 10:34 AM, Francesco Potortì <address@hidden> wrote:
>>Actually, I want to generate a multiarmed spiral such as this:
>>http://octave.1599824.n4.nabble.com/file/n4644183/Multiarmed.Spiral.png
>>Can someone help?
>
> Those look like circular arcs with a common point.  If that is what you
> want, you write a function to draw an arc given the subtended angle and
> two extreme points, then you call it eight times with appropriate
> parameters.
>
> --
> Francesco Potortì (ricercatore)        Voice:  +39.050.315.3058 (op.2111)
> ISTI - Area della ricerca CNR          Mobile: +39.348.8283.107
> via G. Moruzzi 1, I-56124 Pisa         Fax:    +39.050.315.2040
> (entrance 20, 1st floor, room C71)     Web:    http://fly.isti.cnr.it
> _______________________________________________
> Help-octave mailing list
> address@hidden
> https://mailman.cae.wisc.edu/listinfo/help-octave

If you see the possible representation of one arm of your spirals (I
think the exponential form is missing something)
http://en.wikipedia.org/wiki/Logarithmic_spiral

you can imagine how to make a function that does a multi-arm one.

For example
spiral=@(t,a,b) a*(exp(b*t)-1);
t = linspace(0,2,100)'*2*pi;
y = spiral (t,1,0.5);
polar (t+[pi/2 pi 3*pi/2],y)


-- 
M. Sc. Juan Pablo Carbajal
-----
PhD Student
University of Zürich
http://ailab.ifi.uzh.ch/carbajal/