gnuplot-info

[Gnuplot-info] Plot one additional point, manually

[Allan F. <all...@ya...>]

Hi, I would like to plot a set of points which is being generated by a C
code, using pipe. It would plot a sequence of these points making a video.
Here is an example that does the job:

----------------------------------------------------------------

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

int main() {

    FILE *pipe;
    pipe = popen("gnuplot -persist", "w");

    fprintf(pipe, "set xlabel 'x (m)' \n");
    fprintf(pipe, "set ylabel 'y (m)' \n");
    fprintf(pipe, "set pointsize 1 \n");
    fprintf(pipe, "set xrange[-0.1:4.1] \n");
    fprintf(pipe, "set yrange[-0.1:4.1] \n");

    int i;
    double x, y;

    for (i = 1; i < 30; i++) {
        x = (double) rand() / RAND_MAX;
        y = (double) rand() / RAND_MAX;

        fprintf(pipe, "plot '< echo %lf, %lf' w p pt 7 lc -1 notitle \n",
4*x, 4*y);

        fflush(pipe);
        usleep(150000);
    }

    fclose(pipe);
    return 0;
}

-------------------------------------------------------------------------------------

It works ... however, the way it is done, it plots just one point at a time.
I would like to plot one point, then another one, but keeping the last point
... then another, keeping all the other 2 ... so I'd like to know how I
could add one point to a graph that is already done, that would solve my
problem.
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Re: [Gnuplot-info] Plot one additional point, manually

[walter h. <wh...@bf...>]

I think what you need is  libplot from gnu plot utils, it supports things like animated gifs.

see:
http://www.gnu.org/software/plotutils/manual/en/html_node/Sample-C-Drawings.html#Sample-C-Drawings


re,
 wh


Am 19.02.2012 02:56, schrieb Allan Felipe:
> 
> Hi, I would like to plot a set of points which is being generated by a C
> code, using pipe. It would plot a sequence of these points making a video.
> Here is an example that does the job:
> 
> ----------------------------------------------------------------
> 
> #include <stdio.h>
> #include <stdlib.h>
> #include <unistd.h>
> 
> int main() {
> 
>     FILE *pipe;
>     pipe = popen("gnuplot -persist", "w");
> 
>     fprintf(pipe, "set xlabel 'x (m)' \n");
>     fprintf(pipe, "set ylabel 'y (m)' \n");
>     fprintf(pipe, "set pointsize 1 \n");
>     fprintf(pipe, "set xrange[-0.1:4.1] \n");
>     fprintf(pipe, "set yrange[-0.1:4.1] \n");
> 
>     int i;
>     double x, y;
> 
>     for (i = 1; i < 30; i++) {
>         x = (double) rand() / RAND_MAX;
>         y = (double) rand() / RAND_MAX;
> 
>         fprintf(pipe, "plot '< echo %lf, %lf' w p pt 7 lc -1 notitle \n",
> 4*x, 4*y);
> 
>         fflush(pipe);
>         usleep(150000);
>     }
> 
>     fclose(pipe);
>     return 0;
> }
> 
> -------------------------------------------------------------------------------------
> 
> It works ... however, the way it is done, it plots just one point at a time.
> I would like to plot one point, then another one, but keeping the last point
> ... then another, keeping all the other 2 ... so I'd like to know how I
> could add one point to a graph that is already done, that would solve my
> problem.

Re: [Gnuplot-info] Plot one additional point, manually

[Stephen W. <ste...@in...>]

Allan Felipe wrote:
> Hi, I would like to plot a set of points which is being generated by a C
> code, using pipe. It would plot a sequence of these points making a video.
> Here is an example that does the job:
>
> ----------------------------------------------------------------
>
> #include<stdio.h>
> #include<stdlib.h>
> #include<unistd.h>
>
> int main() {
>
>      FILE *pipe;
>      pipe = popen("gnuplot -persist", "w");
>
>      fprintf(pipe, "set xlabel 'x (m)' \n");
>      fprintf(pipe, "set ylabel 'y (m)' \n");
>      fprintf(pipe, "set pointsize 1 \n");
>      fprintf(pipe, "set xrange[-0.1:4.1] \n");
>      fprintf(pipe, "set yrange[-0.1:4.1] \n");
>
>      int i;
>      double x, y;
>
>      for (i = 1; i<  30; i++) {
>          x = (double) rand() / RAND_MAX;
>          y = (double) rand() / RAND_MAX;
>
>          fprintf(pipe, "plot '<  echo %lf, %lf' w p pt 7 lc -1 notitle \n",
> 4*x, 4*y);
>
>          fflush(pipe);
>          usleep(150000);
>      }
>
>      fclose(pipe);
>      return 0;
> }
>
> -------------------------------------------------------------------------------------
>
> It works ... however, the way it is done, it plots just one point at a time.
> I would like to plot one point, then another one, but keeping the last point
> ... then another, keeping all the other 2 ... so I'd like to know how I
> could add one point to a graph that is already done, that would solve my
> problem.
>    
I make animations using a fortran calling code
for each time step (while the code is ececuting).

  call SYSTEM("/usr/bin/gnuplot explosion.gnu")

Each time step adds an additional point.
Hope this helps,
Stephen


-- 
ste...@in...
2004 route des lucioles - BP93
Sophia Antipolis
06902 CEDEX
		
Tel: 04 92 38 50 54
Fax: 04 97 15 53 51

Re: [Gnuplot-info] Plot one additional point, manually

[Thomas S. <t.s...@fz...>]

Allan Felipe <allanfelipebr <at> yahoo.com.br> writes:

> 
> 
> Hi, I would like to plot a set of points which is being generated by a C
> code, using pipe. It would plot a sequence of these points making a video.
> Here is an example that does the job:
> 
> ----------------------------------------------------------------
> 
> #include <stdio.h>
> #include <stdlib.h>
> #include <unistd.h>
> 
> int main() {
> 
>     FILE *pipe;
>     pipe = popen("gnuplot -persist", "w");
> 
>     fprintf(pipe, "set xlabel 'x (m)' \n");
>     fprintf(pipe, "set ylabel 'y (m)' \n");
>     fprintf(pipe, "set pointsize 1 \n");
>     fprintf(pipe, "set xrange[-0.1:4.1] \n");
>     fprintf(pipe, "set yrange[-0.1:4.1] \n");
> 
>     int i;
>     double x, y;
> 
>     for (i = 1; i < 30; i++) {
>         x = (double) rand() / RAND_MAX;
>         y = (double) rand() / RAND_MAX;
> 
>         fprintf(pipe, "plot '< echo %lf, %lf' w p pt 7 lc -1 notitle \n",
> 4*x, 4*y);
> 
>         fflush(pipe);
>         usleep(150000);
>     }
> 
>     fclose(pipe);
>     return 0;
> }
> 
>
--------------------------------------------------------------------------------
> 
> It works ... however, the way it is done, it plots just one point at a time.
> I would like to plot one point, then another one, but keeping the last point
> ... then another, keeping all the other 2 ... so I'd like to know how I
> could add one point to a graph that is already done, that would solve my
> problem.

maybe the 'replot' command helps:

for (i = 0; i<  30; i++) {
   x = (double) rand() / RAND_MAX;
   y = (double) rand() / RAND_MAX;
   if (i) {
      fprintf(pipe,
         "replot '<  echo %lf, %lf' w p pt 7 lc -1 notitle \n",
         4*x, 4*y);
   } else {
      fprintf(pipe,
         "plot '<  echo %lf, %lf' w p pt 7 lc -1 notitle \n",
         4*x, 4*y);
   }
   fflush(pipe);
   usleep(150000);
}

Re: [Gnuplot-info] Plot one additional point, manually

[Allan F. <all...@ya...>]

Hi, people, thanks for the answers. ( I am new here, I received 3 answers in
my e-mail, shouldn't I also see them here in the forum? )
If possible I would like to keep the tool C pipe to Gnuplot. In fact, I
found out a solution, but it is not elegant at all.  I could save the data
to a file and then read this file from inside a loop, each time adding one
line. So, I plot a graphic with just 1 line, then 2 lines, then 3 lines ...
I think it's not elegant because I need to save a file and then read it
again, instead of using the data which is being generated.
 
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Re: [Gnuplot-info] Plot one additional point, manually

[Hans-Bernhard B. <HBB...@t-...>]

On 20.02.2012 03:54, Allan Felipe wrote:
> Hi, people, thanks for the answers. ( I am new here, I received 3 answers in
> my e-mail, shouldn't I also see them here in the forum? )

This is not a forum, it's a mailing list.  And IIRC it's configured to 
avoid sending duplicates to the direct recipient.

> I think it's not elegant because I need to save a file and then read it
> again, instead of using the data which is being generated.

Well, like I said before: gnuplot is not designed to work the way you 
want to.  Ultimately the data has to be stored /somewhere/.  Since 
gnuplot doesn't store them, that means either it has to be stored in 
your program (and you send it all again for every re-draw), or it's 
stored somewhere else (e.g. in a file).

Re: [Gnuplot-info] Plot one additional point, manually

[Allan F. <all...@ya...>]

> maybe the 'replot' command helps:

> for (i = 0; i<  30; i++) {
>    x = (double) rand() / RAND_MAX;
>    y = (double) rand() / RAND_MAX;
>    if (i) {
>       fprintf(pipe,
>          "replot '<  echo %lf, %lf' w p pt 7 lc -1 notitle \n",
>          4*x, 4*y);
>    } else {
>       fprintf(pipe,
>          "plot '<  echo %lf, %lf' w p pt 7 lc -1 notitle \n",
>          4*x, 4*y);
>    }
>    fflush(pipe);
>    usleep(150000);
> }

Yes, that solution also works ! However I tested it and it's really slow.
Saving the data to a file and reading it is faster, like:

--------------------------------------------------------------------------------------------------------------

    FILE *output;
    output = fopen("data.txt", "w");

    for (i = 1; i <= MAX; i++) {
        x = (double) rand() / RAND_MAX;
        y = (double) rand() / RAND_MAX;

	fprintf(output, "%lf %lf \n", x, y);
    }

    fclose(output);

    for (i = 1; i <= MAX; i++) {
        fprintf(pipe, "plot 'data.txt' every ::1::%d using ($1*4):($2*4) pt
7 lc -1 notitle \n", i);
        fflush(pipe);
	usleep(1000);
    }

-----------------------------------------------------------------------------------------------------------

Then, so far, I guess that's an acceptable way of using the C environment
for making animations. And if I need some extra flexibility I could save
each image and merge them with ffmpeg.
About the mailing list, I'm sending the messages through Nabble forum and I
keep receiving : Your recent message has not yet been accepted by the
mailing list and is still in the pending status. So I think it is weird that
I'm getting answers, and the mailing list actually receives my messages.
-- 
View this message in context: http://old.nabble.com/Plot-one-additional-point%2C-manually-tp33350361p33374456.html
Sent from the Gnuplot - User mailing list archive at Nabble.com.

Re: [Gnuplot-info] Plot one additional point, manually

[Allan F. <all...@ya...>]

> maybe the 'replot' command helps:

> for (i = 0; i<  30; i++) {
>    x = (double) rand() / RAND_MAX;
>    y = (double) rand() / RAND_MAX;
>    if (i) {
>       fprintf(pipe,
>          "replot '<  echo %lf, %lf' w p pt 7 lc -1 notitle \n",
>          4*x, 4*y);
>    } else {
>       fprintf(pipe,
>          "plot '<  echo %lf, %lf' w p pt 7 lc -1 notitle \n",
>          4*x, 4*y);
>    }
>    fflush(pipe);
>    usleep(150000);
> }

Yes, that solution also works ! However I tested it and it's really slow.
Saving the data to a file and reading it is faster, like:

--------------------------------------------------------------------------------------------------------------

    FILE *output;
    output = fopen("data.txt", "w");

    for (i = 1; i <= MAX; i++) {
        x = (double) rand() / RAND_MAX;
        y = (double) rand() / RAND_MAX;

	fprintf(output, "%lf %lf \n", x, y);
    }

    fclose(output);

    for (i = 1; i <= MAX; i++) {
        fprintf(pipe, "plot 'data.txt' every ::1::%d using ($1*4):($2*4) pt
7 lc -1 notitle \n", i);
        fflush(pipe);
	usleep(1000);
    }

-----------------------------------------------------------------------------------------------------------

Then, so far, I guess that's an acceptable way of using the C environment
for making animations. And if I need some extra flexibility I could save
each image and merge them with ffmpeg.
About the mailing list, I'm sending the messages through Nabble forum and I
keep receiving : Your recent message has not yet been accepted by the
mailing list and is still in the pending status. So I think it is weird that
I'm getting answers, and the mailing list actually receives my messages.
-- 
View this message in context: http://old.nabble.com/Plot-one-additional-point%2C-manually-tp33350361p33374457.html
Sent from the Gnuplot - User mailing list archive at Nabble.com.