What I'm saying its that "I better prefer to explore than decode". I don't want to study. I want to get to the point I'm searching.
To plot a function you just define it and it will show to you. Go to the console, write gnuplot and do
[...] f(x,a,b) = a*x**2 + b plot f(x,10,30) title 'the simplest plot' [...]
you will get this
to change the format style (color, line type: doted, dashed, lines-points) do
[...] plot f(x,10,30) with linespoints pointsize 0.5 pointtype 2 linecolor rgb "black" title 'f(x,a,b) with lines and points' [...]
Change the parameters as you wish to get another stuff.
- Tables
Now we will generate a table of $x$-$y$ data and plot it as it was a data file we had for something else
[...] ## Using functions to generate data : tables set output 'f(x,a,b).table' set table plot f(x,10,30) unset table reset # If you don't reset you will print the results on 'f(x,a,b).table' ## Ploting data from a file plot 'f(x,a,b).table' using 1:2 t 'Plotting from a file' [...]
You get the same you got but as it was data
- Parametric plots
You need to make a grid (there are another ways, but that will be shared later). A grid is just a table of $x$-$y$ points. Your computer always discretizes the space in order to evaluate the function you with to it. In 2D the grid is just a straight line. So we do,
[...] set xrange [0:2*pi] # Yes, pi is defined within gnuplot, awesome ha? No less that one should expect! set yrange [-1:1] set output 'xy-grid.table' # This is the output file to use later set table plot x unset table reset # If you don't reset you will print the results on 'xy-grid.table' plot 'xy-grid.table' using 1:2 title "The grid is a line if you are not a curved space dealer" [...]
Which looks like
Now we use the file "xy-grid.table" to plot whatever function we want using explicit parameterization
of the axes.We will use the axes
[...] set size square # This sets the scale of 'x' the same as 'y' 1 to 1 proportion plot 'xy-grid.table' using ( cos($2) ):( sin($2) ) title 'this was a fucking line!!', \ 'xy-grid.table' using ( cos($2)/5 ):( sin($2)/5 ) title 'this was another fucking line!!' [...]I plotted two "different" parametrizations, so you can see how its done.
That's all!
Bye