> | restart; |
> |
> | f1:=(t,x,y,z)->10*y-10*x; |
> | f2:=(t,x,y,z)->28*x-y-x*z; |
> | f3:=(t,x,y,z)->-8/3*z+x*y; |
> | t0:=0:x0:=5:y0:=5:z0:=5: |
> | XY:=[x0,y0]:XYZ:=[x0,y0,z0]: |
> | h:=0.01:n:=2000:t:=t0:x:=x0:y:=y0:z:=z0: |
> | for i from 1 to n do |
> | a:=f1(t,x,y,z):b:=f2(t,x,y,z):c:=f3(t,x,y,z): |
> | u:=x+h*a:v:=y+h*b:w:=z+h*c: |
> | x:=x+h*(a+f1(t+h,u,v,w))/2:y:=y+h*(b+f2(t+h,u,v,w))/2:z:=z+h*(c+f3(t+h,u,v,w))/2: |
> | XY:=(XY,[x,y]):XYZ:=(XYZ,[x,y,z]): |
> | t:=t+h: |
> | od: |
> | with(plots): |
> | pointplot3d({XYZ}); |
> |