(!*******************************************************
   Mosel Example Problems
   ======================

   file mandelbrotsub.mos
   ``````````````````````
   Mandelbrot function: f(z) = z^2 + c with z,c complex numbers.

   Submodel for solving the function for all points in the
   rectangular box (MINX,MINY,MAXX,MAXY).

   - Testing Java GUI with distributed computing -

   *** Not intended to be run standalone - run from mandelbrot.java ***

   (c) 2010 Fair Isaac Corporation
       author: S. Heipcke, June 2010, rev. Sep. 2018
  *******************************************************!)

model "mandelbrot (sub)"
  uses "mmjobs" 
 
  parameters
    CONFIG=3                    ! Color scheme and zoom
    MINX = 0                    ! Min/Max X/Y coordinates of box solved by this model
    MAXX = 0
    MINY = 0
    MAXY = 0
    HX = 0.1                    ! Distance between points
    HY = 0.1
    NUM = 0                     ! Model ID
    MAX_ITER = 1000             ! Iteration limit for Mandelbrot function 
    IODRV = "bin:zlib.deflate:"    ! File format: compressed binary
  end-parameters	

  declarations
    x,y: real
    SOL: dynamic array(range,range) of integer
  end-declarations 
 

!***************** Subroutines ******************
  function PXcolor(r,g,b:real): integer
    returned:= round(r + g*256 + b*65536) 
  end-function 

! Color for a pixel on the screen    (x0,y0) = (x,y) co-ordinates of pixel
  function pixel_color(x0,y0: real): integer 
    x:= 0
    y:= 0
    iterct:= 0
 
    while ( x*x + y*y <= (2*2)  and  iterct < MAX_ITER ) do
      xtemp := x*x - y*y + x0
      y:= 2*x*y + y0
      x:= xtemp
      iterct += 1
    end-do
    if iterct = MAX_ITER then 
      returned := 0     ! Black
    else 
      if CONFIG = 0 then
       returned := PXcolor(round((iterct) mod 255), 255-round(iterct*2 mod 255), 255-round((ln(iterct)*40) mod 255))
      elif CONFIG = 1 then
       returned := PXcolor(round((iterct) mod 255), round((ln(iterct)*50) mod 255), 255-round(iterct mod 255))
      elif CONFIG = 2 then
       returned := PXcolor(iterct*3 mod 255, round(iterct*2 mod 255), 255-round(iterct*3 mod 255))
      elif CONFIG = 3 then
       returned := PXcolor(ln(iterct)*50 mod 255, round(iterct*2 mod 255), 255-round(iterct*1.5 mod 255))
      elif CONFIG = 4 then
       returned := PXcolor(255-(iterct mod 255), 255-round(iterct*2 mod 255), round(iterct mod 255))
      end-if
    end-if  
 end-function

!***************** Main ******************
  
 ! Do the actual calculation for a box and save the solution
   forall(x0 in MINX..MAXX, y0 in MINY..MAXY)  
     SOL(x0,y0):= pixel_color(x0*HX,y0*HY)
   initializations to IODRV+"rmt:solmod"+NUM+".txt"
     SOL as "sol"
   end-initializations

   exit(NUM)

end-model