how to draw 1D plot

[Loylick]

Hi!

I was looking through the documentation but I could not figure out how to make graphic output of a simiple 1D plot like one I attached to this post.
I had to output my data to a file and draw the graph by hand to show it to you. My data are just two columns: X, Y. When I look at gnuplot file generated by
Dealii I see that it tries to draw my data as 2D plot.
Regards, Alex

    MatrixOut matrix_out;
    FullMatrix<double> DBvsF;
    DBvsF.reinit(2, 1000);
    std::vector<double>   frequency;
   

    double w;
    double e = parameters.get_double("dissip");
    unsigned int l;
    unsigned int sz = frequency.size()-1;
   
    for ( l=0; l<1000 ;  l++) {
        step = sqrt(w);
        w+=step;
        double val = log(DbAtFreq(w, &frequency, e));
        DBvsF(0, l)= w;
        DBvsF(1, l) = val;
    }
       

   std::ofstream out("DBvsFrequency.plt");
   matrix_out.build_patches(DBvsF, "M");
   matrix_out.write_gnuplot(out);

[Wolfgang Bangerth]

That's too complicated. MatrixOut is intended to visualize the elements of a
matrix, but you really just want to visualize pairs (x_i,y_i). Just output
these one by one to a file:

ofstream output("M");
for (l=0...) {
...
output << w << ' ' << val << std::endl;
}

and then visualize the resulting data using gnuplot's "plot" command.

Best
W.



--
------------------------------------------------------------------------
Wolfgang Bangerth email: bang...@colostate.edu
www: http://www.math.colostate.edu/~bangerth/

[Loylick]

Thank you, I thought that there was a more generic way of drawing 1D plots in Dealii.