Question

我有一个C ++程序，使用嵌入式lua脚本将数据点从程序写入文件，我希望能够同时运行gnuplot实例来绘制数据点。

 select
    coalesce(A.ID, B.ID, C.ID) as ID,
    A.ColA, A.ColB, B.ColC, B.ColD, B.ColE, C.ColF, C.ColG
 from
    (select
      ID,
      row_number() over (partition by ID order by ColA) as rownumber,
      ColA,
      ColB
    from
      TableA t) A
  full outer join
    (select
      ID,
      row_number() over (partition by ID order by ColC) as rownumber,
      ColC,
      ColD,
      ColE
    from
      TableB t) B on B.ID = A.ID and B.rownumer = A.rownumber
  full outer join
    (select
      ID,
      row_number() over (partition by ID order by ColF) as rownumber,
      ColF,
      ColG
    from
      TableC t) C on C.ID = nvl(A.ID, B.ID) and C.rownumer = A.rownumber

gnuplot文件如下所示：

io.output(pfile);
io.write(t, "\t", p_x, "\t", p_y, "\t", p_z, "\n");

上面的gnuplot脚本适用于完整的数据文件，但我希望它在程序运行时实时绘制。当lua脚本写入文件时，有时gnuplot脚本会捕获具有不完整的最后一行的文件。这会产生错误：

set termopt enhanced

set title "Linear Momentum Vector"
set xlabel "t (s)"
set ylabel "p (N-s)"

plot "data/plot_p.dat" using 1:2 title "p_x(t)" with lines, \
     "data/plot_p.dat" using 1:3 title "p_y(t)" with lines, \
     "data/plot_p.dat" using 1:4 title "p_z(t)" with lines

set style line 81 lt 0 lc rgb "#808080" lw 0.5

set grid xtics ytics mxtics mytics
set grid back ls 81

pause 0.25
reread

如何让gnuplot编写最后一行或无效数据集的脚本？

谢谢！

Answer 1

有些乱搞lua实际上为我解决了它。在io.write（...）调用之后调用io.flush（）函数似乎每次都将完整的行写入文件。

当然，并没有告诉gnuplot SKIP或IGNORE的最后一行，但确保最后一行完整。

Gnuplot：跳过数据文件的最后/不完整行

1 个答案: