上下文 mptopdf 问题

Question

我对以下文件有问题

input graph 
  u=0.5cm; 
beginfig(0); 
draw dashpattern(on 5bp); 
picture pa; 
pa=currentpicture; 
currentpicture:=nullpicture; 
draw dashpattern(on 5bp off 2bp); 
picture pb; 
pb=currentpicture; 
currentpicture:=nullpicture; 
draw dashpattern(on 1bp off 2bp); 
picture pc; 
pc=currentpicture; 
currentpicture:=nullpicture; 
draw dashpattern(on 5bp off 2bp on 1bp off 2bp); 
picture pd; 
pd=currentpicture; 
currentpicture:=nullpicture; 
draw dashpattern(on 5bp off 2bp on 5bp off 2bp on 1bp off 2bp on 1bp off 2bp); 
picture pe; 
pe=currentpicture; 
currentpicture:=nullpicture; 
draw dashpattern(on 5bp off 2bp on 5bp off 2bp on 1bp off 2bp ); 
picture pf; 
pf=currentpicture; 
currentpicture:=nullpicture; 
draw dashpattern(on 1bp off 2bp on 1bp off 2bp on 5bp off 2bp ); 
picture pg; 
pg=currentpicture; 
currentpicture:=nullpicture; 
  draw begingraph(6cm,6cm); 
  glabel.lft(btex Throughput (bps) etex rotated 90, OUT); 
  glabel.bot(btex sources etex, OUT); 
  gdraw "thr_olsrmos_20_30_300_0.05_1.txt"  withcolor 0.75black dashed pa; 
  draw (12, 1)*u--(14, 1)*u withcolor 0.75black dashed pa; 
  label.bot(btex T=1 Delta=0.05 etex scaled 0.5, (13, 1)*u); 
  label.top(btex OLSR-MOS: etex scaled 0.5, (13, 2)*u); 
  gdraw "thr_olsr_20_30_300.txt" withcolor 0.75red; 
  draw (12, 8)*u--(14, 8)*u withcolor 0.75red; 
  label.bot(btex OLSR etex scaled 0.5, (13, 8)*u); 
  autogrid(grid.bot,grid.lft) withcolor 0.95white; 
  frame.llft; 
  gdraw "thr_olsrmos_20_30_300_0.05_1.txt"  withcolor 0.75black dashed pa; 
  draw (12, 1)*u--(14, 1)*u withcolor 0.75black dashed pa; 
  label.bot(btex T=1 Delta=0.05 etex scaled 0.5, (13, 1)*u); 
  label.top(btex OLSR-MOS: etex scaled 0.5, (13, 2)*u); 
  gdraw "thr_olsr_20_30_300.txt" withcolor 0.75red; 
  draw (12, 8)*u--(14, 8)*u withcolor 0.75red; 
  label.bot(btex OLSR etex scaled 0.5, (13, 8)*u); 
  endgraph; 
endfig; 
end

有人能帮帮我吗？