Re: using gnuplot's "splot" and "every" commands on org-mode table data

[Eric Schulte <schulte.eric@gmail.com>]

Paul Stansell <paulstansell@gmail.com> writes:

> Hi Eric,
>
> There appears to be a slight bug in the way gnuplot handles blocked
> data with missing entries.
>
> An example is provided in the org script at then end of this note.
>
> In the code block gnuplot_1 the use of ':missing "?"' seems to cause
> the exported data file to lack the blanks lines that are essential
> for the plot.  The plot from this code block is incorrect.
>
> In gnuplot_2 ':missing' is not used, but instead 'set datafile missing
> "?"' is set explicitly in the gnuplot code block.  The plot from this
> code block is correct.
>
> Surely gnuplot_1 should produce exactly the same plot as gnuplot_2.
>

Hi Paul,

Currently the :missing header argument for gnuplot code blocks does two
things.  It adds the "set datafile missing..." line to the code block
body *and* it binds `*org-babel-gnuplot-missing*' to the value of the
:missing header argument when the datafile is written, so empty table
cells are replaced with the value of the :missing header argument.

The reason you're not getting a blank line is because it is replaced
with three "missing" values, in this case "? ? ?".

Do you think this behavior should be changed or split between two header
arguments?

Thanks,

>
> Kind regards,
>
> Paul
>
>
> Exported data file does not include blank lines.
> #+name: gnuplot_1
> #+begin_src gnuplot :var d=block_data_missing :missing "?" :results silent
>   set ticslevel 0
>   splot d index 0 u 1:2:3 w lp pt 6 ps 5, d index 1 u 1:2:3 w lp pt 6 ps 5
> #+end_src
>
> Exported data file includes blank lines.
> #+name: gnuplot_2
> #+begin_src gnuplot :var d=block_data_missing :results silent
>   set datafile missing "?"
>   set ticslevel 0
>   splot d index 0 u 1:2:3 w lp pt 6 ps 5, d index 1 u 1:2:3 w lp pt 6 ps 5
> #+end_src
>
> #+name: block_data_missing
> | 1 | 1 |  2 |
> | 1 | 2 |  5 |
> | 1 | 3 | 10 |
> |   |   |    |
> | 2 | 1 |  5 |
> | 2 | 2 | 10 |
> | 2 | 3 | 13 |
> |   |   |    |
> | 3 | 1 | 10 |
> | 3 | 2 |  ? |
> | 3 | 3 | 18 |
> |   |   |    |
> |   |   |    |
> | 1 | 1 | 12 |
> | 1 | 2 | 15 |
> | 1 | 3 | 20 |
> |   |   |    |
> | 2 | 1 | 15 |
> | 2 | 2 | 18 |
> | 2 | 3 | 23 |
> |   |   |    |
> | 3 | 1 |  ? |
> | 3 | 2 | 23 |
> | 3 | 3 | 28 |
>
>
>
>
>

-- 
Eric Schulte
https://cs.unm.edu/~eschulte
PGP: 0x614CA05D