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File:Cardioid under log mapping.png

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Summary

Description
English: cardioid under log mapping[1]
Date
Source Own work
Author Adam majewski

Source code

/*

 b batch file for maxima CAS



There are 2 complex planes :
* w-plane 
* z-plane 


z is a pont of z-planes
zz is a list of z points

1. draw curve on z plane 
2. draw images of z-curve  under f  on w plane               
3. draw images of z-curve under fc on w plane 




Adam Majewski
 
*/

kill(all);
remvalue(all);


/* definitions of  functions  */

f(z):= float(rectform(log(z)))$
fc(z):= float(rectform(log(z -c)))$


/* conformal map */
 g(w):=w/2-w*w/4;
 
 /* 
 circle D={w:abs(2w)=1 } where w=l(t) 
 t is angle in turns ; 1 turn = 360 degree = 2*Pi radians 
 */
 l(t):=%e^(%i*t*2*%pi);


/* converts complex number into list for draw package  */
draw_format(z):= [float(realpart(z)),float(imagpart(z))];



compile(all);



print (" ============== compute ===============  ")$
/* ---- const ----*/ 

t : (-1+sqrt(5))/2$ /* Rotation number ( internal angle) t is an irrational number = the Golden Mean  */ 
c :l(t)$
c:g(c)$


/*  c : -0.39054087 -0.58678790*%i$ */ 
 iMax:100; /* number of points to draw */
 dt:1/iMax;
 


/* curve is a list of points joned by lines */
 /* point to point method of drawing */
 t:0; /* angle in turns */ 
 /* compute first point of curve, create list and save point to this list */
 /* point of unit circle   w:l(t); */
 w:rectform(ev(l(t), numer)); 
 circleList:makelist (w, j, 1, 1); 
 while (t<=1) do
 (  t:t+dt,
    w:rectform(ev(l(t), numer)), 
    circleList:cons(w,circleList)
 );
 
 
 zz:[0, 1/4, 1/3, 1/2]$
 zz:map(l,zz)$
 zz:map(g,zz)$
 

 cardioidList: map (g, circleList)$	
 
 /* --------- map from z to w plane using   -------------------------------*/
 logList:      map (f, cardioidList)$
 logCList:     map (fc, cardioidList)$
 
 ww : map(f,zz)$
 wwc: map(fc,zz)$
 
 
/*--------------  convert lists of complex points to draw format lists --------*/

cardioidList: points(map(draw_format, cardioidList))$
 logList:     points(map(draw_format, logList))$
 logCList:    points(map(draw_format, logCList))$

 zz: points(map(draw_format, zz))$
 ww: points(map(draw_format, ww))$
 wwc: points(map(draw_format, wwc))$

/*------------------  draw ------------------------------------------------------ */

path:"~/Dokumenty/mandelbrot_planes/log/maxima/"$ /* pwd  */
FileName:"i3p"$ /* without extension which is the terminal name */





 load(draw); /* Mario Rodríguez Riotorto   http://www.telefonica.net/web2/biomates/maxima/gpdraw/index.html */
 draw(
  terminal  = 'png,
  file_name = concat(path,FileName),
  columns  = 3,
  dimensions=[1500,500], /*  x = y*columns  */
  
  gr2d(title = " z plane ",
   xlabel     = "z.re ",
   ylabel     = "z.im",
   points_joined =true,
   grid = false,
   color         = red,
   point_size    = 0.2,
   point_type = filled_circle,
   cardioidList,
   
   color=blue,
   points_joined =false,
   point_size    = 0.9,
   zz
   
  ),

  gr2d(
   title = " w plane : w =log(z)",
   xlabel     = "w.re ",
   ylabel     = "w.im",
   grid = false,
   xaxis       = false,
   points_joined =true,
   color         = red,
   point_size    = 0.2,
   point_type = filled_circle,
   logList,
   
   color=blue,
   points_joined =false,
   point_size    = 0.9,
   ww
),
gr2d(
   title = " w plane : w =log(z-c)",
   xlabel     = "w.re ",
   ylabel     = "w.im",
   /*
   yrange = [-0.5,3.5],
   xrange = [-2.5,1.5],
   */
   grid = false,
   xaxis       = false,
   points_joined =true,
   color         = red,
   point_size    = 0.2,
   point_type = filled_circle,
   logCList,
   
   color=blue,
   points_joined =false,
   point_size    = 0.9,
   wwc
   
)

 );



Licensing

I, the copyright holder of this work, hereby publish it under the following license:
w:en:Creative Commons
attribution share alike
This file is licensed under the Creative Commons Attribution-Share Alike 4.0 International license.
You are free:
  • to share – to copy, distribute and transmit the work
  • to remix – to adapt the work
Under the following conditions:
  • attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
  • share alike – If you remix, transform, or build upon the material, you must distribute your contributions under the same or compatible license as the original.
  1. Frontiers in complex dynamics by Curtis T. McMullen

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cardioid under log mapping

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