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<DIV><FONT face=Arial size=2>Hi,</FONT></DIV>
<DIV><FONT face=Arial size=2>I wrote a C program that simulates the Lorenz
attractor</FONT></DIV>
<DIV><FONT face=Arial size=2>and plots the results. The graphic mode should
be set.</FONT></DIV>
<DIV><FONT face=Arial size=2>Here is the basic subroutine. Maybe somebody
will find</FONT></DIV>
<DIV><FONT face=Arial size=2>it useful.</FONT></DIV>
<DIV><FONT face=Arial size=2>
<DIV><FONT face=Arial size=2>Regards</FONT></DIV>
<DIV><FONT face=Arial size=2>Jarek</FONT></DIV></FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>void Lorenz(void)<BR>{<BR>/* simulation variables/parameters:
*/<BR> float x = 0.1;<BR> float y = 0.0;<BR>
float z = 0.0;<BR> float s = 10.00;<BR> float r =
28.00;<BR> float b = 2.67;<BR> float dt =
100E-6;<BR>/* graphics' variables/parameters: */<BR> float xxscale =
0.02*(float)(getmaxx()+1); /* for plot scaling */<BR>
float yyscale = 0.01*(float)(getmaxy()+1); /* for plot scaling
*/<BR> WORD xx0 = (getmaxx()+1)/2; /*
plot center x */<BR> WORD yy0 =
(getmaxy()+1)/2; /* plot center y
*/<BR> WORD color = 15;</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>/* border, x and y axes: */<BR>
setcolor(DARKGRAY);<BR>
rectangle(0,0,getmaxx(),getmaxy());<BR> line(0,yy0,getmaxx(),yy0);
line(xx0,0,xx0,getmaxx());<BR>/* loop: */<BR> while ( kbhit() )
getch();<BR> do<BR> {<BR>
float dx,dy,dz;<BR> WORD
xx,yy;</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2> /* put a pixel: */<BR> xx
= xx0+(int)(xxscale*x); yy = yy0-(int)(yyscale*z);<BR>
putpixel(xx,yy,color);<BR> /* new x,y,z values:
*/<BR> dx = dt * (s*(y-x));<BR> dy = dt *
(r*x - y - x*z);<BR> dz = dt * (x*y -
b*z);<BR> x += dx; y += dy; z += dz;<BR> /*
next color: */<BR> color++; if ( color > 15 ) color =
0;<BR> }<BR> while ( !kbhit() );<BR>}</FONT></DIV>
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