Gnuplot and Sierpinksi Triangle

Question

Question:

I have a code, which hopefully makes a Sierpinski triangle, and I am wondering how can I output a data file that you read into gnuplot? I h

Answer 1

First of all, you have a couple of problems in your code:

• Integer division is leading to only the third option being considered, because 1/3 = 0 and 2/3 = 0. Use 1./3. and 2./3. instead.
• You have exchanged coordinates for the last option, x0 = 1.0; y0 = sqrt3; should be x0 = sqrt3; y0 = 1.0; instead.

Once you output the points to a file called data (I used System.out.println("" + x + " " + y); within your loop), you can do the following in gnuplot:

set size ratio -1
plot "data" u 2:1 pt 7 ps 0.3

To monitor how the triangle gets created dot by dot you can use a loop with a pause:

set xrange [0:2]
set yrange [0:1.8]
do for [i=0:4999] {
plot "data" u 2:1 every ::::i pt 7 ps 0.3
pause 0.1
}

Or you can create an animated gif with a series of png files:

set term pngcairo
do for [i=0:4999] {
set output "".i.".png"
plot "data" u 2:1 every ::::i pt 7 ps 0.3
}

Expect the above to be slow. You can skip some of the frames to make it quicker. Then do this outside gnuplot:

convert -delay 10 -loop 0 *.png animation.gif

For this example I used 50 points increments and changed -delay to 100: