Re: matlab m-file

[Adam Majewski]

Hi,

I have made code that works in my Octave ( see below).
Can I improve it ?

TIA

Adam
#----------code start -------------------

# http://www.dhushara.com/DarkHeart/DarkHeart.htm
# it is Octave m-file
# converted from matlab m-file by Chris King
# http://www.dhushara.com/DarkHeart/Viewers/source/siegel.m
#

# ------------- load packages ------------------------
pkg load image;
pkg load miscellaneous; # waitbar


# --------- definitions ------------------------------

function [potential myfl] = Mlevel(zx,zy,c,maxiter)

 z = complex(zx,zy);
 ang=0;
 iter = 0;

 while (iter < maxiter)&&(abs(z) > 0.001)&&(abs(z)<20)
   h=z;
   z=z*z+c;
     hh=abs(z-h)*(z-h);
     if iter>maxiter/2
       ang=ang+hh;
    end
   iter = iter+1;
 end

 if iter < maxiter
    potential = iter;
    if abs(z)>=20  myfl=0;
             else  myfl=1;
    end
 else
    potential=abs(ang);
    myfl=2;
 end
endfunction; # Mlevel

# ------------- const ------------------------------
# function siegel();

# integer ( screen ) coordinate
nx = 480;
ny = 480;

# image as a 2D matrix of 24 bit colors
MyImage = zeros(nx,ny,3); # matrix filled with 0

# world ( float) coordinate - dynamical (Z) plane
magc=0.65;
dSide=1/magc;
Zxmin = -dSide;
Zxmax = dSide;
Zymin = -dSide;
Zymax = dSide;

stepy = (Zymax - Zymin)/(ny - 1); # pixel height
stepx = (Zxmax - Zxmin)/(nx - 1); # pixel width

maxiter = 1200;

# fc(z) = z*z + c
th=pi*(-1+sqrt(5)); # rotation number or internal angle
d=exp(complex(0,th)); #
c =d/2-d*d/4; # point on boundary of main cardioid
# a=4;
pi4=pi/4;

# --------------- main ---------------------

waitbar(0,'Please wait...'); # info

# scan all pixels of image and comput color
for iy = 1:ny
  Zy = Zymin + iy*stepy; # map from screen to world coordinate
  for ix= 1:nx
    Zx = Zxmin + ix*stepx;
    [k myfl] = Mlevel(Zy,Zx,c, maxiter);
    if      myfl==2 MyImage(ix,iy,2) = abs(sin(5*k/10 + pi4));
    else if myfl==1 MyImage(ix,iy,1) = abs(sin(2*k/10));
        else        MyImage(ix,iy,3) = abs(cos(2*k/10)); # myfl==0

        end # else
    end # else
  end # for ix
  waitbar(iy/ny);
end # for iy

# image

image(MyImage); # display image
imwrite(MyImage,'si2.jpg');  # save image to file
# this requires the ImageMagick "convert" utility.



#---------------- code end ----------


On 27.10.2011 17:49, Adam Majewski wrote:
> Hi,
> I woould like to run Matlab m-file :
> http://www.dhushara.com/DarkHeart/Viewers/source/siegel.m
>
>
> using GNU Octave, version 3.2.3
>
> I have packages :
>
> octave-3.2.3:2> pkg list
> Package Name | Version | Installation directory
> -------------------+---------+-----------------------
> ftp *| 1.0.2 | /usr/share/octave/packages/3.2/ftp-1.0.2
> general *| 1.1.3 | /usr/share/octave/packages/3.2/general-1.1.3
> image *| 1.0.10 | /usr/share/octave/packages/3.2/image-1.0.10
> io *| 1.0.9 | /usr/share/octave/packages/3.2/io-1.0.9
> miscellaneous *| 1.0.9 | .../share/octave/packages/3.2/miscellaneous-1.0.9
> missing-functions *| 1.0.2 |
> .../octave/packages/3.2/missing-functions-1.0.2
> plot *| 1.0.7 | /usr/share/octave/packages/3.2/plot-1.0.7
>
>
> Program "works" without error codes but it does not creates image file.
>
> What can I do to create image ?
>
> TIA
>
>
> Adam