Lorenz equation example

Here is another example, the familar strange attractor of the Lorenz equations:

The above is NOT from vplot. Rather, it is an example of what gnuplot is capable of.

Above is a plot of a x(t),y(t) and z(t). The projection in the (x,z) plane is plotted. But suppose you want also to plot information about y(t) on a two-dimensional plot. One possibility is to represent the value of y with a color: shading from blue for negative towards red for positive. However, the familiar plotting programs might not give you these sort of capabilities, and you will need to make such a plot from graphics primitives:

The above is plotted using vplot. y(t) is indicated by the color, with red positive and blue negative.

• Download lorenz.py and make it executable. Then simply type lorenz.py. If all went well, a file lorenz.dat was made.

• The gnuplot rendition can be reproduced with gnuplot:

  gnuplot> set term png color
  gnuplot> set output 'gnuplot_attactor.png'
  gnuplot> plot [-15:15][0:30] 'lorenz.dat' using 2:4 with lines
  gnuplot> exit            
  

• The vplot rendition is made with lorplot.py.