Re: Bug in script for plotting

[c.]

On 8 Feb 2013, at 20:41, Ben Abbott <address@hidden> wrote:

> 
> On Feb 8, 2013, at 7:41 AM, c. wrote:
> 
>> 
>> On 8 Feb 2013, at 01:59, Ben Abbott <address@hidden> wrote:
>> 
>>> On Feb 7, 2013, at 5:28 PM, stn wrote:
>>> 
>>>> Hi,
>>>> 
>>>> this is kind of irritating. It has also probably been discussed before.
>>>> 
>>>> 
>>>> The plot-command works fine, the plot appears as expected, but on the 
>>>> terminal there is a message
>>>> 
>>>> gnuplot> nset obj 1;
>>>>       ^
>>>>       line 0: invalid command
>>>> 
>>>> 
>>>> After lots of googling and some grepping I found this line in 
>>>> /usr/local/share/octave/3.6.3/m/plot/private/__go_draw_axes__.m
>>>> 
>>>> Only there it says "unset obj". More specifically it says "fputs 
>>>> (plot_stream, "unset obj 1; \\\n");"
>>>> 
>>>> The problem can be solved by replacing every occurence of "unset obj" in 
>>>> the script with " unset obj".
>>>> 
>>>> It would appear that the function fputs() does not work correctly and 
>>>> truncates the first character of this string. The solution mentioned above 
>>>> simply adds a space-character, that is then truncated.
>>>> 
>>>> I would like to suggest checking the matter.
>>>> 
>>>> Best regards, stn
>>> 
>>> I've seen this mentioned before, but I do not get this error.  For example, 
>>> each of the following work for me.
>>> 
>>>     plot (rand (3))
>>>     surf (peaks ())
>>>     contour (peaks ())
>>> 
>>> I'm using gnuplot 4.6 patchlevel 1 
>>> 
>>> Can you tell us what version of gnuplot you are using (just in case that is 
>>> involved in some way).  Also, can you provide a short script that produces 
>>> the error for you so that we may try to duplicate it?
>>> 
>>> Ben
>> 
>> Ben,
>> 
>> I run the development Octave version, I have gnuplot 4.6 patch level 1 
>> (installed via macports) and XQuartz 2.7.4 on OSX 10.8.2.
>> I can consistently reproduce the same issue reported by stn as follows:
>> 
>> 1) stop XQuartz
>> 2) plot (randn (3))
>> 
>> the issue can be simply worked around by adding a space in front of all 
>> instances of "unset obj 1" as stn suggested, it seems the first character in 
>> sent to the pipe is getting lost somehow …
>> 
>> c.
> 
> Carlo,
> 
> I produced a plot-stream by ...
> 
>       plot (rand (3))
>       drawnow ("aqua", "/dev/null", false, "debug.gp")
> 
> The "unset obj 1" command comes at the end of binary data record, whose 
> ending looks like below in vi.
> 
> @@@@@@@@@@@@ @ @"@"@address@hidden@unset obj 1;
> 
> I'm thinking the problem may be with the binary record (not with the unset 
> command).
> 
> Perhaps some padding should be added after each binary record?  This may just 
> break things (works for me), but does the diff below eliminate the problem 
> for you?
Yes, it does.

> diff --git a/scripts/plot/private/__go_draw_axes__.m 
> b/scripts/plot/private/__go_draw_axes__.m
> --- a/scripts/plot/private/__go_draw_axes__.m
> +++ b/scripts/plot/private/__go_draw_axes__.m
> @@ -2027,6 +2027,7 @@
>       endif
>     endif
>   endif
> +  fprintf (plot_stream, "\n # pad the plotstream\n")
> 
> endfunction
> Ben
c.