Dear all, I need some help with this program I have. I ran this recursive system only to find that it stopped working at 1.89Gb. Anyone out there knows the problem or maybe there's a better way of writing this program? I'm using Maple 12. The codes are as below: restart; Digits:=16; x[0]:=-10.0;y[0]:=0;z[0]:=37.0; a := 35.0;b := 3.0;c := 28.0; h:=0.001;t[0]:=0;n:=0; for n from 0 to 7000 by 1 do for i from 0 to 3 by 1 do x[i+1] := x[i] + int((-exp(a*(s-t)))*(diff(subs(t=s,x[i]),s)- a*subs(t=s,y[i])+ a*subs(t=s,x[i])),s=t[n]..t); y[i+1] := y[i] + int((-exp(c*(t-s)))*(diff(subs(t=s,y[i]),s)+(a-c)*subs(t=s,x[i])+ subs(t=s,x[i])*subs(t=s,z[i])- c*subs(t=s,y[i])),s=t[n]..t); z[i+1] := z[i] + int((-exp(b*(s-t)))*(diff(subs(t=s,z[i]),s)- (subs(t=s,x[i]))*(subs(t=s,y[i]))+ b*subs(t=s,z[i])),s=t[n]..t); end do; x[0]:=evalf(subs(t=t[n]+h,x[4])); y[0]:=evalf(subs(t=t[n]+h,y[4])); z[0]:=evalf(subs(t=t[n]+h,z[4])); Go1[n+1]:=x[0]; Go2[n+1]:=y[0]; Go3[n+1]:=z[0]; t[n+1]:=t[n]+h; end do: i:=0; for t from 0.001 by h to 7 do value[i]:=t; i:=i+1 end do: fd := fopen("D:\\Maple Exercise\\Go\\Go4ite001b3.dat", WRITE); fprintf(fd," t x(t) y(t) z(t) \n"); for k from 0 to i-1 by 1 do fprintf(fd,"%5.3f %20.16f %20.16f %20.16f\n", value[k], Go1[k+1], Go2[k+1] , Go3[k+1]); end do: fclose(fd); Thank you.... sumei